more bug catching after changing the location of data

also cleanup comment from previous bug
moved varibles passed from vbr to .data section
2024-12-19 18:59:34 -05:00 · 2024-12-19 15:18:28 -05:00 · 2024-12-19 13:13:46 -05:00 · 2024-10-16 11:58:57 -04:00 · 2024-10-15 20:37:49 -04:00 · 2024-10-15 20:01:24 -04:00
38 changed files with 2793 additions and 2672 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,9 @@
 out/*
 build/*
 *.img
 *.img.gz
 *.elf
-bx_enh_dbg.ini
+bx_enh_dbg.ini
 stevia-log
 .vscode/
 *.map
--- a/59
+++ b/59
@@ -1,31 +1,39 @@
 iso := 'disk.img'
 include := './include'
-mbr_source_files := $(wildcard src/mbr/*.s)
+mbr_source_files := $(wildcard src/mbr/*.nasm)
-vbr_source_files := $(wildcard src/vbr/*.s)
+vbr_source_files := $(wildcard src/vbr/*.nasm)
-stage2_source_files := $(wildcard src/stage2/*.s)
+stage2_source_files := $(wildcard src/stage2/*.nasm)
-boottest_source_files := $(wildcard src/miniboot32/*.s)
+boottest_source_files := $(wildcard src/miniboot32/*.nasm)
-mbr_binary_files := $(patsubst src/mbr/%.s, build/%.bin, $(mbr_source_files))
+mbr_binary_files := $(patsubst src/mbr/%.nasm, build/%.bin, $(mbr_source_files))
-vbr_binary_files := $(patsubst src/vbr/%.s, build/%.bin, $(vbr_source_files))
+vbr_binary_files := $(patsubst src/vbr/%.nasm, build/%.bin, $(vbr_source_files))
-stage2_binary_files := $(patsubst src/stage2/%.s, build/%.bin, $(stage2_source_files))
+stage2_binary_files := $(patsubst src/stage2/%.nasm, build/%.bin, $(stage2_source_files))
-boottest_binary_files := $(patsubst src/miniboot32/%.s, build/%.bin, $(boottest_source_files))
+boottest_binary_files := $(patsubst src/miniboot32/%.nasm, build/%.bin, $(boottest_source_files))
 build_dir := 'build'
-qemu_args := -L ./bin/ -bios bios.bin -cpu pentium3 -m 64 -S -s -monitor stdio -nic none
+# Get current Git version (tag) and hash
-.PHONY: all mbr vbr stage2 boottest clean run run_bochs iso
+GIT_VERSION := $(shell git describe --tags)
 GIT_HASH := $(shell git rev-parse HEAD)
 GIT_NASM_DEFINES := -D __GIT_VER__='"$(GIT_VERSION)"' -D __GIT_HASH__='"$(GIT_HASH)"'
-all: $(iso) $(mbr_binary_files) $(vbr_binary_files) $(stage2_binary_files)
+iso := '/tmp/disk.img'
 isoz := 'disk.img.gz'
 qemu_args := -L ./bin/ -bios bios.bin -cpu pentium3 -m 128 -S -s -monitor stdio -nic none
 .PHONY: all mbr vbr stage2 boottest clean run run_bochs iso isoz
 all: $(iso) $(isoz) $(mbr_binary_files) $(vbr_binary_files) $(stage2_binary_files)
 mbr: $(mbr_binary_files)
 vbr: $(vbr_binary_files)
 stage2: $(stage2_binary_files)
 boottest: $(boottest_binary_files)
 clean:
 	@rm -rvf *.map
 	@rm -rvf $(build_dir)/*
 	@rm -rvf $(iso)
 	@rm -rvf $(isoz)
 run: $(iso)
 	@sudo qemu-system-i386 $(qemu_args) -hda $(iso)
@@ -34,25 +42,30 @@ run_bochs: $(iso)
 	@bochs -q
 iso: $(iso)
-	@file disk.img
+	@file $(iso)
-build/%.bin: src/mbr/%.s
+isoz: $(isoz)
-	@mkdir -p $(shell dirname $@)
+	@file $(isoz)
 	@nasm -i$(include) -Wall -f bin $< -o $@
-build/%.bin: src/vbr/%.s
+build/%.bin: src/mbr/%.nasm
 	@mkdir -p $(shell dirname $@)
-	@nasm -i$(include) -Wall -f bin $< -o $@
+	@nasm -i$(include) -Wall -f bin $(GIT_NASM_DEFINES) $< -o $@
-build/%.bin: src/stage2/%.s
+build/%.bin: src/vbr/%.nasm
 	@mkdir -p $(shell dirname $@)
-	@nasm -i$(include) -Wall -f bin $< -o $@
+	@nasm -i$(include) -Wall -f bin $(GIT_NASM_DEFINES) $< -o $@
-build/%.bin: src/miniboot32/%.s
+build/%.bin: src/stage2/%.nasm
 	@mkdir -p $(shell dirname $@)
-	@nasm -i$(include) -Wall -f bin $< -o $@
+	@nasm -i$(include) -Wall -f bin $(GIT_NASM_DEFINES) $< -o $@
 build/%.bin: src/miniboot32/%.nasm
 	@mkdir -p $(shell dirname $@)
 	@nasm -i$(include) -Wall -f bin $(GIT_NASM_DEFINES) $< -o $@
 $(iso): $(mbr_binary_files) $(vbr_binary_files) $(stage2_binary_files) $(boottest_binary_files)
 	@echo root access needed to create disk image...
 	@sudo scripts/create-disk.sh
 $(isoz): $(iso)
 	@gzip -9kc $(iso) > $(isoz)
--- a/README.md
+++ b/README.md
@@ -1,85 +1,70 @@
-# stevia
+# Stevia Bootloader
-This is a hobby project that aims to create a simple and lightweight operating system kernel. It is written in Assembly and C, and uses the GNU toolchain and Bochs emulator. The project features (or is hoping to feature):
+Stevia is a lightweight, hobby bootloader written in Assembly and C, designed for educational purposes. It targets x86 (Pentium III era) and aims to be simple, approachable, and understandable, focusing on minimalism and core functionality.
- A boot loader that loads the kernel from a floppy disk image
+## Features
 - A kernel that implements basic functions, such as printing messages, handling interrupts, and managing memory
 - A shell that allows user input and execution of commands
 - A simple text editor that can create and edit files
 - A calculator that can perform arithmetic operations
 - (big maybe) micropython or some other language, cross compiling, etc...
-## Why?
+### Currently Implemented
-I enjoy bare metal programing and I have an old Dell system with a Pentium 3, I did this mostly to learn how to write a legacy style bootloader (I am also kinda working on a UEFI bootloader/utility as well!)
+- **Stage 1 Bootloader**: Loads from the Master Boot Record (MBR) and prepares the system for Stage 2.
 - **Stage 2 Bootloader**: Loads the kernel into memory and passes control.
 - **Basic Filesystem Support**: Initial filesystem recognition (details depend on implemented filesystem support).
 - **Memory Map Parsing**: Detects available memory regions via BIOS interrupts.
 - **GDT Initialization**: Sets up the Global Descriptor Table for protected mode.
 ### In Progress
 - **Interrupt Descriptor Table (IDT) Setup**: Setting up basic interrupt handling.
 - **Basic Keyboard Input**: Initial support for capturing keystrokes.
 ### Planned Features
 - **Task Scheduling**: Basic round-robin task switching.
 - **Filesystem Expansion**: Support for additional filesystems.
 - **More Robust Driver Support**: Additional hardware drivers, such as for storage devices.
 ## Installation
-To build and run this project, you need to have the following tools installed:
+### Prerequisites
- A host system running Linux, macOS (should work 🤷‍♀️), or Windows 11 with WSL2/WSLg
+To build and run Stevia, you will need the following tools installed on your system:
 - GNU Binutils
 - GNU GCC
 - GNU Make
 - NASM
 - Bochs (for testing, project might run on other virtuization/emulation platforms, I target the Pentium 3 Era with this project)
-To build the project, run `make` in the root directory. This will generate a floppy disk image named `stevia.img` that contains the boot loader and the kernel.
+- **Assembler**: NASM for assembling bootloader components.
 - **C Compiler**: GCC (cross-compiler recommended).
 - **Emulator**: Bochs or QEMU for testing.
 - **GNU Make**: For building the project.
 - **Utilities**:
  - **dd**: For creating raw disk images.
  - **losetup** (Linux only): For associating loop devices with disk images.
  - **sfdisk**: For creating DOS disk partitions.
  - **mkfs.fat**: For formatting partitions as FAT32.
  - **hdiutil** (macOS only): For attaching disk images.
  - **newfs\_msdos** (macOS only): For formatting FAT32 partitions.
-To run the project, run `bochs -f bochsrc.txt` in the root directory. This will launch the Bochs emulator and load the floppy disk image. You should see the boot loader message, followed by the kernel message, and then the shell prompt.
+### Building and Running
-To exit the emulator, press `Ctrl+C` in the terminal where you launched Bochs.
+1. **Clone the repository**:
   ```sh
   git clone https://github.com/Nivirx/stevia.git
   cd stevia
   ```
 2. **Build the bootloader and create a bootable disk image**:
   ```sh
   sudo make
   ```
 3. **Run using Bochs**:
   ```sh
   bochs -f bochsrc.txt
   ```
-To run the project on real hardware I use a SD card to IDE interface for my test system which is a ~700Mhz P3 with 256 MB of ram. You will need to write the 'stevia.img' to the disk with 'dd'. On real hardware you may encounter issues that are not accounted for since most of the development happens on bochs, please report any issues you encounter.
+## Project Goals
 Stevia is intended to be a learning tool for those interested in low-level programming, focusing on understanding the basics of how a computer starts up and manages early system resources. Contributions and forks are welcome, especially from those interested in expanding the functionality.
 ## Contributing
 We welcome contributions! Feel free to open issues for bugs or feature requests, and submit pull requests for any improvements. Please ensure that your code follows the existing style and includes appropriate comments.
 ## License
-This project is licensed under the MIT License. See the [LICENSE.md](^2^) file for details.
+This project is licensed under the MIT License. See the [LICENSE](LICENSE) file for more details.
 ### mbr/mbr.s
 This file contains the code for a Master Boot Record (MBR) that attempts to find an active partition to load. The CPU is assumed to be in 16-bit real mode at this point and the bios has loaded the 1st sector of the disk (512 bytes) to 0x0000:0x7C00. First the mbr code relocates from 0x7C00 to 0x0600 and then jumps to the entry point. the loader attempts to load the first active partition it can find and loads the vbr to 0x7c00 (512 bytes) and then jumps to 0x0000:0x7C00. It is written in Assembly and uses BIOS interrupts to read sectors from disk.[^note]
 ### vbr/vbr.s
 This file contains the code for a Volume Boot Record (VBR) that loads the stage2 loader code from the booted disk. It reads disk sectors 1-63 into memory to STAGE2_ENTRY(defaults to 0x7E00 in config.inc) this currently allows for stevia to load up to 32KiB of code to perform bootloader duties. It is written in Assembly and uses BIOS interrupts to read sectors from disk.[^note]
 ### stage2/stage2.s
 This file contains the code for a second-stage boot loader that loads additional modules from disk, performs some system sanity checks, and provides a simple boot interface for options/configuration. It is written in Assembly and uses BIOS interrupts to read sectors from disk.[^note]
 ### miniboot32/BOOT_386.s
 This file contains the code for a 32-bit binary that can be loaded and ran with stevia as a mini demo. It is written in Assembly.[^note]
 ### scripts/create-disk.sh
 This script creates a disk image file for stevia. The disk image file can be used to boot stevia on an emulator or a real machine.
 #### Requirements
 - Bash shell
 - Root privileges
 - dd utility
 - sfdisk utility (for Linux) or hdiutil & util-linux utility (for macOS, util-linux is needed for sfdisk because hdiutil only creates hybrid disks on newer versions afaik)
 - newfs_msdos utility (for macOS)
 - mkfs.vfat utility (for Linux)
 #### Usage
 Run the script as root (or just allow the make script to do its business):
 ```bash
 sudo ./create_disk_image.sh
 ```
 The script will create a disk image file named `disk.img` in the current directory. The disk image file will have the following characteristics:
 - Size: 128 MiB
 - Partition table: DOS
 - Partition 1: FAT32, bootable, starts at sector 2048, contains the boot32 boot test file (`BOOT_386.bin`)
 - Boot code: MBR (`mbr.bin`), VBR (`vbr.bin`), stage2 (sectors 1-63) (`stage2.bin`)
 The script will also copy the necessary files from the `build` directory to the disk image file. If the files are not found, the script will exit with an error.
 [^note]: **Note:** Please note that the assembly code is strictly targeting the Pentium 3 Katmai uArch, but it might run elsewhere. Your mileage may vary.
--- a/bochsrc.bxrc
+++ b/bochsrc.bxrc
@@ -0,0 +1,52 @@
 # configuration file generated by Bochs
 plugin_ctrl: voodoo=false, unmapped=true, biosdev=true, speaker=true, extfpuirq=true, parallel=true, serial=true, busmouse=false, e1000=false, es1370=false, gameport=true, iodebug=true, ne2k=false, sb16=false, usb_uhci=false, usb_ohci=false, usb_ehci=false, usb_xhci=false
 config_interface: win32config
 display_library: win32
 memory: guest=64, host=64, block_size=128
 romimage: file="C:\Program Files\Bochs-2.8\BIOS-bochs-legacy", address=0x00000000, options=none, flash_data=none
 vgaromimage: file="C:\Program Files\Bochs-2.8\VGABIOS-lgpl-latest"
 boot: disk
 floppy_bootsig_check: disabled=1
 floppya: type=1_44
 # no floppyb
 ata0: enabled=true, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
 ata0-master: type=disk, path=".\disk.img", mode=flat, cylinders=0, heads=16, spt=63, sect_size=512, model="Stevia Disk", biosdetect=auto, translation=auto
 ata0-slave: type=none
 ata1: enabled=false
 ata2: enabled=false
 ata3: enabled=false
 optromimage1: file=none
 optromimage2: file=none
 optromimage3: file=none
 optromimage4: file=none
 optramimage1: file=none
 optramimage2: file=none
 optramimage3: file=none
 optramimage4: file=none
 pci: enabled=1, chipset=i440fx, slot1=none, slot2=none, slot3=none, slot4=none, slot5=none
 vga: extension=vbe, update_freq=10, realtime=1, ddc=builtin
 cpu: count=1, ips=1000000, model=p3_katmai, reset_on_triple_fault=1, cpuid_limit_winnt=0, ignore_bad_msrs=1, mwait_is_nop=0
 print_timestamps: enabled=0
 debugger_log: -
 magic_break: enabled=1
 port_e9_hack: enabled=true, all_rings=false
 iodebug: all_rings=0
 private_colormap: enabled=0
 clock: sync=none, time0=local, rtc_sync=0
 # no cmosimage
 log: -
 logprefix: %t%e%d
 debug: action=ignore
 info: action=report
 error: action=report
 panic: action=ask
 keyboard: type=mf, serial_delay=150, paste_delay=100000, user_shortcut=none
 mouse: type=none, enabled=false, toggle=ctrl+mbutton
 sound: waveoutdrv=dummy, waveout=none, waveindrv=dummy, wavein=none, midioutdrv=dummy, midiout=none
 speaker: enabled=true, mode=sound, volume=15
 parport1: enabled=false
 parport2: enabled=false
 com1: enabled=false
 com2: enabled=false
 com3: enabled=false
 com4: enabled=false
--- a/bochsrc.dbg.txt
+++ b/bochsrc.dbg.txt
@@ -0,0 +1,53 @@
 # configuration file generated by Bochs
 plugin_ctrl: voodoo=false, unmapped=true, biosdev=true, speaker=true, extfpuirq=true, parallel=true, serial=true, busmouse=false, e1000=false, es1370=false, gameport=true, ne2k=false, sb16=false, usb_uhci=false, usb_ohci=false, usb_ehci=false, usb_xhci=false
 config_interface: textconfig
 display_library: sdl2, options=gui_debug
 memory: guest=64, host=64, block_size=128
 romimage: file="/usr/share/bochs/BIOS-bochs-legacy", address=0x00000000, options=none, flash_data=none
 vgaromimage: file="/usr/share/bochs/VGABIOS-lgpl-latest"
 boot: disk
 floppy_bootsig_check: disabled=0
 floppya: type=1_44
 # no floppyb
 ata0: enabled=true, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
 ata0-master: type=disk, path="./disk.img", mode=flat, cylinders=0, heads=0, spt=0, sect_size=512, model="Stevia Disk", biosdetect=auto, translation=auto
 ata0-slave: type=none
 ata1: enabled=false
 ata1-master: type=none
 ata1-slave: type=none
 ata2: enabled=false
 ata3: enabled=false
 optromimage1: file=none
 optromimage2: file=none
 optromimage3: file=none
 optromimage4: file=none
 optramimage1: file=none
 optramimage2: file=none
 optramimage3: file=none
 optramimage4: file=none
 pci: enabled=1, chipset=i440fx, slot1=none, slot2=none, slot3=none, slot4=none, slot5=none
 vga: extension=vbe, update_freq=10, realtime=1, ddc=builtin
 cpu: count=1, ips=1000000, model=p3_katmai, reset_on_triple_fault=0, cpuid_limit_winnt=0, ignore_bad_msrs=1, mwait_is_nop=0
 print_timestamps: enabled=0
 private_colormap: enabled=0
 clock: sync=none, time0=local, rtc_sync=0
 # no cmosimage
 log: stevia-log
 #logcontrol: disk=1, rombios=1, pci=0, cpu=0, keyboard=0, io=0
 logprefix: %t%e%d
 debug: action=ignore
 info: action=report
 error: action=report
 panic: action=ask
 keyboard: type=mf, serial_delay=150, paste_delay=100000, user_shortcut=none
 mouse: type=none, enabled=false, toggle=ctrl+mbutton
 sound: waveoutdrv=dummy, waveout=none, waveindrv=dummy, wavein=none, midioutdrv=dummy, midiout=none
 speaker: enabled=true, mode=sound, volume=15
 parport1: enabled=true, file=none
 parport2: enabled=false
 com1: enabled=true, mode=null
 com2: enabled=false
 com3: enabled=false
 com4: enabled=false
 magic_break: enabled=1
 port_e9_hack: enabled=1, all_rings=false
--- a/bochsrc.txt
+++ b/bochsrc.txt
@@ -1,25 +1,35 @@
 # configuration file generated by Bochs
-plugin_ctrl: unmapped=true, biosdev=true, speaker=true, extfpuirq=true, parallel=true, serial=true, gameport=true, iodebug=true
+plugin_ctrl: voodoo=false, unmapped=true, biosdev=true, speaker=true, extfpuirq=true, parallel=true, serial=true, busmouse=false, e1000=false, es1370=false, gameport=true, ne2k=false, sb16=false, usb_uhci=false, usb_ohci=false, usb_ehci=false, usb_xhci=false
-config_interface: wx
+config_interface: textconfig
 display_library: wx
-memory: host=64, guest=64
+memory: guest=64, host=64, block_size=128
 romimage: file="/usr/share/bochs/BIOS-bochs-legacy", address=0x00000000, options=none, flash_data=none
 vgaromimage: file="/usr/share/bochs/VGABIOS-lgpl-latest"
 boot: disk
 floppy_bootsig_check: disabled=0
-# no floppya
+floppya: type=1_44
 # no floppyb
 ata0: enabled=true, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
-ata0-master: type=disk, path="./disk.img", mode=flat, cylinders=0, heads=0, spt=0, sect_size=512, model="Generic 1234", biosdetect=auto, translation=auto
+ata0-master: type=disk, path="./disk.img", mode=flat, cylinders=0, heads=0, spt=0, sect_size=512, model="Stevia Disk", biosdetect=auto, translation=lba
 ata0-slave: type=none
 ata1: enabled=false
 ata1-master: type=none
 ata1-slave: type=none
 ata2: enabled=false
 ata3: enabled=false
-pci: enabled=0
+optromimage1: file=none
-vga: extension=vbe, update_freq=5, realtime=1
+optromimage2: file=none
-cpu: count=1:1:1, ips=1000000, quantum=16, model=p3_katmai, reset_on_triple_fault=1, cpuid_limit_winnt=0, ignore_bad_msrs=1, mwait_is_nop=0
+optromimage3: file=none
 optromimage4: file=none
 optramimage1: file=none
 optramimage2: file=none
 optramimage3: file=none
 optramimage4: file=none
 pci: enabled=1, chipset=i440fx, slot1=none, slot2=none, slot3=none, slot4=none, slot5=none
 vga: extension=vbe, update_freq=10, realtime=1, ddc=builtin
 cpu: count=1, ips=1000000, model=p3_katmai, reset_on_triple_fault=1, cpuid_limit_winnt=0, ignore_bad_msrs=1, mwait_is_nop=0
 print_timestamps: enabled=0
-debugger_log: -
+port_e9_hack: enabled=false, all_rings=false
 magic_break: enabled=0
 port_e9_hack: enabled=0
 private_colormap: enabled=0
 clock: sync=none, time0=local, rtc_sync=0
 # no cmosimage
@@ -29,12 +39,15 @@ debug: action=ignore
 info: action=report
 error: action=report
 panic: action=ask
-keyboard: type=mf, serial_delay=250, paste_delay=100000, user_shortcut=none
+keyboard: type=mf, serial_delay=150, paste_delay=100000, user_shortcut=none
-mouse: type=ps2, enabled=false, toggle=ctrl+mbutton
+mouse: type=none, enabled=false, toggle=ctrl+mbutton
-speaker: enabled=true, mode=system
+sound: waveoutdrv=dummy, waveout=none, waveindrv=dummy, wavein=none, midioutdrv=dummy, midiout=none
-parport1: enabled=false
+speaker: enabled=true, mode=sound, volume=15
 parport1: enabled=true, file=none
 parport2: enabled=false
 com1: enabled=true, mode=null
 com2: enabled=false
 com3: enabled=false
 com4: enabled=false
 magic_break: enabled=1
 port_e9_hack: enabled=1, all_rings=false
--- a/docs/Stevia
+++ b/docs/Stevia
@@ -0,0 +1,230 @@
 # **Bootloader Documentation**
 ## **1. Calling Conventions**
 ### __cdecl16near Calling Convention
 - **Purpose**: For calling near (within the same segment) functions in 16-bit code.
 - **Stack Management**: Caller cleans up the stack after the function call.
 - **Parameter Passing**: Parameters are pushed onto the stack from right to left.
 - **Return Address**: A near return address (16-bit) is pushed onto the stack.
 - **Return Value**: Placed in the AX register.
 Example:
 ```assembly
 ; Caller
 push param2
 push param1
 call near_func
 add sp, 4  ; Clean up the stack (2 parameters * 2 bytes each)
 ; Callee (near_func)
 near_func:
  push bp
  mov bp, sp
  ; Function body
  mov sp, bp
  pop bp
  ret
 ```
 ### __cdecl16far Calling Convention
 - **Purpose**: For calling far (across different segments) functions in 16-bit code.
 - **Stack Management**: Caller cleans up the stack after the function call.
 - **Parameter Passing**: Parameters are pushed onto the stack from right to left.
 - **Return Address**: A far return address (32-bit, consisting of a segment and an offset) is pushed onto the stack.
 - **Return Value**: Placed in the AX register.
 Example:
 ```assembly
 ; Caller
 push param2
 push param1
 call far_func
 add sp, 4  ; Clean up the stack (2 parameters * 2 bytes each)
 ; Callee (far_func)
 far_func:
  push bp
  mov bp, sp
  ; Function body
  mov sp, bp
  pop bp
  retf  ; Far return
 ```
 ### **Key Differences**
 - **Return Address**: `__cdecl16near` uses a 16-bit return address; `__cdecl16far` uses a 32-bit return address (segment:offset).
 - **Function Scope**: `__cdecl16near` is for functions within the same segment; `__cdecl16far` is for functions that may be in different segments.
 - **Return Instruction**: `__cdecl16near` uses `ret`; `__cdecl16far` uses `retf` (far return).
 ### **Register Usage**
 #### Caller-Saved (Volatile) Registers
 - **AX**: Accumulator, often used for return values.
 - **CX**: Counter register.
 - **DX**: Data register, used for I/O operations.
 - **SI/DI**: String operation indexes.
 #### Callee-Saved (Non-Volatile) Registers
 - **BP**: Base pointer, used for stack frame management.
 - **SP**: Stack pointer.
 - **BX**: Base register.
 Example:
 ```assembly
 ; Caller
 push param2
 push param1
 call near_func
 add sp, 4  ; Clean up the stack (2 parameters * 2 bytes each)
 ; Callee (near_func)
 near_func:
  push bp
  mov bp, sp
  ; Save callee-saved registers if used
  push bx
  push si
  push di
  ; Function body
  ; Use AX, CX, DX freely
  ; Restore callee-saved registers
  pop di
  pop si
  pop bx
  mov sp, bp
  pop bp
  ret
 ```
 ## **2. E820 Memory Map Usage**
 ### **Address Range Descriptor Structure**
 | Offset | Name          | Description                           |
 |--------|---------------|---------------------------------------|
 | 0      | BaseAddrLow    | Low 32 bits of base address           |
 | 4      | BaseAddrHigh   | High 32 bits of base address          |
 | 8      | LengthLow      | Low 32 bits of length in bytes        |
 | 12     | LengthHigh     | High 32 bits of length in bytes       |
 | 16     | Type           | Address type of this range            |
 ### **E820 Function Call**
 #### Input
 - **EAX**: Function code `E820h`.
 - **EBX**: Continuation value for physical memory retrieval (0 for the first call).
 - **ES:DI**: Buffer pointer to an Address Range Descriptor structure.
 - **ECX**: Buffer size (minimum size 20 bytes).
 - **EDX**: Signature ('SMAP').
 #### Output
 - **CF**: Carry flag (indicates success/failure).
 - **EAX**: Signature ('SMAP').
 - **ECX**: Buffer size (number of bytes returned).
 - **EBX**: Continuation value for subsequent E820 calls.
 ### **Address Type Values**
 | Value | Pneumonic            | Description                                               |
 |-------|----------------------|-----------------------------------------------------------|
 | 1     | AddressRangeMemory    | Available RAM usable by the operating system.             |
 | 2     | AddressRangeReserved  | Reserved by the system, unusable by the operating system. |
 ## **3. Example Calculations**
 ### **Partition Offset**
 - Partition 1 offset = LBA 0x800 = 0x100000
 - `bsSectorSize = 512`
 ### **First FAT Sector**
 - `first_fat_sector = bsResSector = 32 => (32*512) = 0x4000`
 - `first_fat_sector = 0x100000 + 0x4000 = 0x104000`
 ### **Total FAT Sectors**
 - `total_fat_sectors = fat_sectors * number_of_FATs = 2001 * 2 = 4002`
 - `total_fat_size = total_fat_sectors * bsSectorSize = 0x1F4400`
 ### **First Data Sector**
 - `first_data_sector = FatStartSector + FatAreaSize = 0x104000 + 0x1F4400 = 0x2F8400`
 ### **FAT Table Look Up**
 ```c
 if the cluster we got from the table entry was cluster 354
 fat_sector = 354 / 128 = 2
 fat_entry  = 354 mod 128 = 98
 so we load the 3rd (indexed from 0) fat table sector and read the 98th entry
 ```
 Example:
 ```c
 fat_table_offset = (first_fat_sector + 2) * 512
 fat_table = *(fat_table_offset)
 disk_read(fat_table[98])
 ```
 ## **4. Global Descriptor Table (GDT)**
 ### **Segment Attributes**
 - **Pr**: Present bit (must be 1 for valid selectors).
 - **Privl**: Privilege level (0 = kernel, 3 = user).
 - **S**: Descriptor type (set for code/data segments, cleared for system segments).
 - **Ex**: Executable bit (set if segment contains code).
 - **DC**: Direction/Conforming bit (for data or code segments).
 - **RW**: Readable/Writable (depends on segment type).
 ### **Granularity (Gr)**
 - **Gr**: Granularity bit (0 = byte granularity, 1 = 4 KiB blocks).
 - **Sz**: Size bit (0 = 16-bit mode, 1 = 32-bit mode).
 ### **GDT Entry Construction**
 Each GDT entry is 8 bytes:
 - First DWORD: Limit (0:15), Base (0:15)
 - Second DWORD: Base (16:31), Attributes (8:12)
 ## **5. Memory Layout Example**
 ### **Low Memory (First MiB)**
 | Start       | End         | Size            | Type                  | Description                      |
 |-------------|-------------|-----------------|-----------------------|----------------------------------|
 | 0x00000000  | 0x000003FF  | 1 KiB           | RAM (partially unusable) | Real Mode IVT (Interrupt Vector Table) |
 | 0x00000400  | 0x000004FF  | 256 bytes       | RAM (partially unusable) | BDA (BIOS data area)             |
 | 0x00000500  | 0x00007BFF  | almost 30 KiB   | RAM - free for use     | Conventional memory              |
 | 0x00007C00  | 0x00007DFF  | 512 bytes       | RAM (partially unusable) | OS BootSector                    |
 | 0x00007E00  | 0x0007FFFF  | 480.5 KiB       | RAM - free for use     | Conventional memory              |
 | 0x00080000  | 0x0009FFFF  | 128 KiB         | RAM (partially unusable) | EBDA (Extended BIOS Data Area)   |
 | 0x000A0000  | 0x000FFFFF  | 384 KiB         | various (unusable)     | Video memory, ROM Area           |
 ### **Extended Memory (Above 1 MiB)**
 | Start       | End         | Size            | Description            |
 |-------------|-------------|-----------------|------------------------|
 | 0x00100000  | 0x00EFFFFF  | 14 MiB          | RAM - free for use     |
 | 0x00F00000  | 0x00FFFFFF  | 1 MiB           | Possible memory-mapped hardware (ISA) |
 | 0x01000000  | ?           | ?               | More extended memory   |
 | 0xC0000000  | 0xFFFFFFFF  | 1 GiB           | Memory mapped PCI devices, BIOS, etc. |
 | 0x0000000100000000 | ?     | ?               | RAM - usable in PAE/64-bit mode |
--- a/docs/examples.txt
+++ b/docs/examples.txt
@@ -1,35 +0,0 @@
 Partition 1 offset = LBA 0x800
                   = 0x100000
 bsSectorSize = 512
 first_fat_sector = bsResSector
               = 32 => (32*512) = 0x4000
               = 0x100000 + 0x4000
               = 0x104000
 total_fat_sectors = fat_sectors * number_of_FATs
                  = 2001 * 2
                  = 4002
 total_fat_size = total_fat_sectors * bsSectorSize
              = 0x1F4400
 first_data_sector = FatStartSector + FatAreaSize
                  = 0x104000 + 0x1F4400
                  = 0x2F8400
 FAT table look up
    if the cluster we got from the table entry was cluster 354
    fat_sector = 354 / 128
               = 2
    fat_entry  = 354 mod 128
               = 98
    so we load the 3rd (indexed from 0) fat table sector and read the 98th entry
    for the cluster chain.
    // bad fake code below
    fat_table_offset = (first_fat_sector + 2) * 512
    fat_table = *(fat_table_offset)
    disk_read(fat_table[98])
--- a/include/BIOS/BIOS_SYS.inc
+++ b/include/BIOS/BIOS_SYS.inc
@@ -0,0 +1,24 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %include 'BIOS/func/a20enable.nasm'
 %include 'BIOS/func/E820_memory_map.nasm'
 %include 'BIOS/func/ext_read.nasm'
 %include 'BIOS/func/video.nasm'
--- a/include/BIOS/func/E820_memory_map.nasm
+++ b/include/BIOS/func/E820_memory_map.nasm
@@ -0,0 +1,88 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_E820MEMORY_MAP
 ; Address Range Descriptor Structure
 ;
 ; Offset in Bytes		Name		Description
 ;	0	    BaseAddrLow		u32 - Low 32 Bits of Base Address
 ;	4	    BaseAddrHigh	u32 - High 32 Bits of Base Address
 ;	8	    LengthLow		u32 - Low 32 Bits of Length in Bytes
 ;	12	    LengthHigh		u32 - High 32 Bits of Length in Bytes
 ;	16	    Type		    u32 - Address type of  this range.
 ;   20      ExtType         u32 -  ACPI 3.0 extended type
 struc AddressRangeDescStruct_t
    .BaseAddrLow    resd 1
    .BaseAddrHigh   resd 1
    .LengthLow      resd 1
    .LengthHigh     resd 1
    .Type           resd 1
    .ExtType        resd 1
 endstruc
 ALIGN 4, db 0x90
 GetMemoryMap:
    __CDECL16_ENTRY
    push es         ; save segment register
 .func:
    mov dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries], 0
    mov eax, 0xE820                         ; select 0xE820 function
    xor ebx, ebx                            ; Continuation value, 0 for the first call
    lea dx, [BIOSMemoryMap]
    shr dx, 4
    mov es, dx
    xor di, di                              ; (BIOSMemoryMap >> 4):0 makes di an index into BIOSMemoryMap
    mov ecx, AddressRangeDescStruct_t_size
    mov edx, 0x534D4150                     ; 'SMAP' magic
 .loop_L1:
    int 0x15
    jc GetMemoryMap.error
    cmp eax, 0x534D4150
    jne GetMemoryMap.no_smap_returned
 .no_error:
    inc dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
    cmp ecx, 20                             ; TODO: maybe this could be handled better than just panicing
    jb GetMemoryMap.nonstandard_e820        ; non-standard entry found 
    cmp ebx, 0
    je GetMemoryMap.endp                    ; 0 in ebx means we have reached the end of memory ranges
    add di, AddressRangeDescStruct_t_size   ; increment di to next descriptor
    mov edx, eax                            ; 'SMAP' to edx
    mov eax, 0xE820                         ; select E820 function
    jmp GetMemoryMap.loop_L1
 .error:
    ERROR STAGE2_MM_E820_MISC_ERR
 .nonstandard_e820:
    ERROR STAGE2_MM_E820_NONSTANDARD
 .no_smap_returned:
    ERROR STAGE2_MM_E820_NO_SMAP
 .endp:
    pop es
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_E820MEMORY_MAP
--- a/include/BIOS/func/a20enable.nasm
+++ b/include/BIOS/func/a20enable.nasm
@@ -0,0 +1,144 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_A20ENABLE
 ;
 ;INT 0x15 Function 2400 - Disable A20
 ;Returns:
 ;
 ;   CF = clear if success
 ;   AH = 0
 ;   CF = set on error
 ;   AH = status (01=keyboard controller is in secure mode, 0x86=function not supported)
 ;
 ;INT 0x15 Function 2401 - Enable A20
 ;Returns:
 ;
 ;   CF = clear if success
 ;   AH = 0
 ;   CF = set on error
 ;   AH = status (01=keyboard controller is in secure mode, 0x86=function not supported)
 ;
 ;INT 0x15 Function 2402 - A20 Status
 ;   Returns:
 ;
 ;   CF = clear if success
 ;   AH = status (01: keyboard controller is in secure mode; 0x86: function not supported)
 ;   AL = current state (00: disabled, 01: enabled)
 ;   CX = set to 0xffff is keyboard controller is no ready in 0xc000 read attempts
 ;   CF = set on error
 ;
 ;INT 0x15 Function 2403 - Query A20 support
 ;Returns:
 ;
 ;CF = clear if success
 ;AH = status (01: keyboard controller is in secure mode; 0x86: function not supported)
 ;BX = status.
 ;
 ;BX contains a bit pattern:
 ;
 ;    Bit 0 - supported on keyboard controller
 ;    Bit 1 - if supported on bit 1 of I/O port 0x92
 ;    Bits 2:14 - Reserved
 ;    Bit 15 - 1 if additional data is available.
 ;
 ; I/O Port 0x92 infomation:
 ;
 ;    Bit 0 - Setting to 1 causes a fast reset
 ;    Bit 1 - 0: disable A20; 1: enable A20
 ;    Bit 2 - Manufacturer defined
 ;    Bit 3 - power on password bytes (CMOS bytes 0x38-0x3f or 0x36-0x3f). 0: accessible, 1: inaccessible
 ;    Bits 4-5 - Manufacturer defined
 ;    Bits 6-7 - 00: HDD activity LED off; any other value is "on"
 ALIGN 4, db 0x90
 EnableA20:
    __CDECL16_ENTRY
    push ds
    push es
 .a20_check:
    cli
    xor ax, ax
    mov es, ax
    not ax                      ; ax = 0xFFFF
    mov ds, ax
    mov di, 0x0500              ; scratch location 1
    mov si, 0x0510              ; scratch location 2
    mov al, byte [es:di]
    push ax                     ; save whatever is at 0x0000:0500, physical location 0x0500
    mov al, byte [ds:si]
    push ax                     ; save whatever is at 0xFFFF:0510 [clarification: 0x100500 physical location (0x100500 - 1MB = 0x0500)]
    mov byte [es:di], 0x00      ; zero non-wraped location and write 0xFF to it after (ab)using wrapping
    mov byte [ds:si], 0xFF      ; if the non-wrapped location is 0xFF, then we wraped and A20 is disabled
    cmp byte [es:di], 0xFF
    pop ax
    mov byte [ds:si], al        ; restore original contents of scratch location 2
    pop ax
    mov byte [es:di], al        ; restore original contents of scratch location 1
    mov ax, 0                   ; return 0 if es:di == ds:si (memory wraps)
    je EnableA20.end_check
    mov ax, 1                   ; return 1 if es:di != ds:si (A20 is enabled)
 .end_check:
    sti
    cmp ax, 1
    je EnableA20.endp         ; A20 is already enabled
    mov ax, 0x2403
    int 0x15
    jc EnableA20.do_fallback_a20    ; carry = error...not supported?
    cmp ah, 0
    ja EnableA20.do_fallback_a20   ; non-zero return = error as well
    mov al, bl
    and al, 0000_0010b
    cmp al, 0000_0010b
    je EnableA20.do_fast_a20        ; if fast a20 is supported use it
    jmp EnableA20.do_bios_a20       ; else fall back to enabling via BIOS
 .do_fallback_a20:
    ERROR STAGE2_A20_FAILED
 .do_bios_a20:
    mov ax, 0x2401
    int 0x15
    jmp EnableA20.a20_check
 .do_fast_a20:
    in al, 0x92                 ; read from FAST A20 port
    or al, 2                    ; bit 0 is a fast reset, bit 1 is fast A20
    and al, 0xFE                ; make sure bit 0 is 0
    out 0x92, al                ; enable A20
    jmp EnableA20.a20_check
 .endp:
    pop es
    pop ds
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_A20ENABLE
--- a/include/BIOS/func/ext_read.nasm
+++ b/include/BIOS/func/ext_read.nasm
@@ -0,0 +1,129 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_EXT_READ
 ;Offset	Size	    Description
 ; 0	    1	    size of packet (16 bytes)
 ; 1	    1	    always 0
 ; 2	    2	    number of sectors to transfer (max 127 on some BIOSes)
 ; 4	    4	    transfer buffer (0xFFFF:0xFFFF)
 ; 8	    4	    lower 32-bits of starting 48-bit LBA
 ; 12	4	    upper 32-bits of starting 48-bit LBA
 ; needs to be aligned to a uint32_t
 struc LBAPkt_t
    .size        resb 1
    .res0        resb 1
    .xfer_size   resw 1
    .offset      resw 1
    .segment     resw 1
    .lower_lba   resd 1
    .upper_lba   resd 1
 endstruc
 ; call_read_disk_raw <word segment> <word offset> <dword lba> <word count> <word drive_num>
 %macro call_read_disk_raw 5
    movzx ax, %5
    push ax                                            ; drive_num
    movzx ax, %4
    push ax                                            ; count
    movzx dword eax, %3
    push dword eax                                     ; lba
    movzx ax, %2
    push ax                                            ; offset
    movzx ax, %1
    push ax                                            ; segment = 0
    ; uint8_t read_stage2_raw(uint16_t buf_segment, uint16_t buf_offset, 
    ;                         uint32_t lba,
    ;                         uint16_t count, uint16_t drive_num)
    call read_disk_raw
    add sp, 0xC
 %endmacro
 ; Wrapper for AH=0x42 INT13h (Extended Read)
 ;
 ; BIOS call details
 ; AH = 42h
 ; DL = drive number
 ; DS:SI -> disk address packet
 ;
 ; Return:
 ; CF clear if successful
 ; AH = 00h
 ; CF set on error
 ; AH = error code
 ; disk address packet's block count field set to number of blocks
 ; successfully transferred
 ;
 ;
 ; uint8_t read_stage2_raw(uint16_t buf_segment, uint16_t buf_offset, 
 ;                         uint32_t lba,
 ;                         uint16_t count, uint8_t drive_num)
 ALIGN 4, db 0x90
 read_disk_raw:
    __CDECL16_ENTRY
 .func:                        
    mov ax, LBAPkt_t_size
    push ax                 ; len
    xor ax, ax
    push ax                 ; val = 0
    mov ax, lba_packet
    push ax                 ; dest = lba_packet address
    call kmemset        
    add sp, 0x06
    mov bx, lba_packet
    mov byte [bx + LBAPkt_t.size], LBAPkt_t_size
    mov ax, [bp + 12]
    mov word [bx + LBAPkt_t.xfer_size], ax
    mov eax, [bp + 8]
    mov dword [bx + LBAPkt_t.lower_lba], eax
    mov ax, [bp + 6]
    mov word [bx + LBAPkt_t.offset], ax
    movzx ax, byte [bp + 4]
    mov word [bx + LBAPkt_t.segment], ax
    mov si, bx                  ; ds:si LBAPkt_t
    mov ah, 0x42                ; call #
    mov dl, byte [bp + 14]      ; drive #             
    int 0x13
    jnc .endf
    %ifdef __STEVIA_MBR
    ERROR MBR_ERROR_DISK_READ_ERR
    %elifdef __STEVIA_VBR
    ERROR VBR_ERROR_DISK_READ_ERR
    %else
    ERROR STAGE2_MBR_DISK_READ_ERROR
    %endif
 .endf:
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_EXT_READ
--- a/include/BIOS/func/video.nasm
+++ b/include/BIOS/func/video.nasm
@@ -0,0 +1,60 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_VIDEO
 ; Sets output to 80x25 16 color text mode via BIOS call
 ; also clears screen
 ; void SetTextMode(void)
 ALIGN 4, db 0x90
 SetTextMode:
 .prolog:
    __CDECL16_ENTRY
    pushf
 .func:
    xor ah, ah                  ; Set Video mode BIOS function
    mov al, 0x02                ; 16 color 80x25 Text mode
    int 0x10                    ; Call video interrupt
    mov ah, 0x05                ; Select active display page BIOS function
    xor al, al                  ; page 0
    int 0x10                    ; call video interrupt
 .endp:
    popf
    __CDECL16_EXIT
    ret
 ; disables blinking text mode cursor
 ALIGN 4, db 0x90
 disable_cursor:
    __CDECL16_ENTRY
 .func:
    mov dx, 0x3D4
 	mov al, 0xA	    ; low cursor shape register
 	out dx, al
 	inc dx
 	mov al, 0x20	; bits 6-7 unused, bit 5 disables the cursor, bits 0-4 control the cursor shape
 	out dx, al
 .endp:
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_VIDEO
--- a/include/cdecl16.inc
+++ b/include/cdecl16.inc
@@ -0,0 +1,57 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifnmacro __CDECL16_ENTRY
 %macro __CDECL16_ENTRY 0
    push bp
    mov bp, sp
    sub sp, 0x10
    push si
    push di
    push bx
 %endmacro
 %endif
 %ifnmacro __CDECL16_EXIT
 %macro __CDECL16_EXIT 0
    pop bx
    pop di
    pop si
    mov sp, bp
    pop bp
 %endmacro
 %endif
 %ifnmacro __CDECL16_CALLER_SAVE
 %macro __CDECL16_CALLER_SAVE 0
    push ax
    push cx
    push dx
 %endmacro
 %endif
 %ifnmacro __CDECL16_CALLER_RESTORE
 %macro __CDECL16_CALLER_RESTORE 0
    pop dx
    pop cx
    pop ax
 %endmacro
 %endif
--- a/include/config.inc
+++ b/include/config.inc
@@ -1,4 +1,4 @@
-; Copyright (c) 2023 Elaina Claus
+; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
@@ -18,8 +18,12 @@
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_STEVIA_CONFIG
 %define SECTOR_SIZE             512
-%define STAGE2_SECTOR_COUNT    0x40
+%define STAGE2_SECTOR_COUNT    0x20
-; 32 KiB
+; 16 KiB
-%define MAX_STAGE2_BYTES      (SECTOR_SIZE * STAGE2_SECTOR_COUNT)
+%define MAX_STAGE2_BYTES      (SECTOR_SIZE * STAGE2_SECTOR_COUNT)
 %endif
 %define __INC_STEVIA_CONFIG
--- a/include/early_mem.inc
+++ b/include/early_mem.inc
@@ -0,0 +1,33 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_EARLY_MEM
 ;PhysicalAddress = Segment * 16 + Offset
 %define SEG_TO_LINEAR(s,o) ((s << 4) + o)
 ; Offset = physical / (Segment * 16)
 %define LINEAR_TO_OFFSET(p,s) ((p / (s << 4)))
 ; Seg = (physical - offset) / 16
 %define LINEAR_TO_SEGMENT(p,o) ((p - o) >> 4)
 %endif
 %define __INC_EARLY_MEM
--- a/include/entry.inc
+++ b/include/entry.inc
@@ -1,4 +1,4 @@
-; Copyright (c) 2023 Elaina Claus
+; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
@@ -18,9 +18,11 @@
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_ENTRY
-; 8KiB from 0x2500 -> 0x500
+%define MBR_ENTRY                    0x8C00
-%define STACK_START            0x2500
+%define VBR_ENTRY                    0x7C00
-%define MBR_ENTRY              0x7A00
+%define STAGE2_ENTRY                 0x0500
-%define VBR_ENTRY              0x7C00
+
-%define STAGE2_ENTRY           0x7E00
+%endif
 %define __INC_ENTRY
--- a/include/error_codes.inc
+++ b/include/error_codes.inc
@@ -1,4 +1,4 @@
-; Copyright (c) 2023 Elaina Claus
+; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
@@ -18,6 +18,7 @@
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_ERROR_CODES
 ; Errors
 ; 12 Errors, 5 in use
@@ -32,7 +33,7 @@
 %define MBR_ERROR_RESERVED_i         'i'
 %define MBR_ERROR_RESERVED_j         'j'
 %define MBR_ERROR_RESERVED_k         'k'
-%define MBR_ERROR_RESERVED_l         'l'
+%define MBR_ERROR_INT13h_EREAD_ERR   'l'
 ; 12 Error
 %define VBR_ERROR_WRONG_FAT_SIZE     'm'
@@ -48,7 +49,7 @@
 %define VBR_ERROR_RESERVED_w         'w'
 %define VBR_ERROR_RESERVED_x         'x'
-; 26 errors, 8 in use
+; 22 errors, 8 in use
 %define STAGE2_A20_FAILED            'A'
 %define STAGE2_SIGNATURE_MISSING     'B'
 %define STAGE2_MM_E820_NO_SUPPORT    'C'
@@ -59,9 +60,9 @@
 %define STAGE2_FAT32_INIT_ERROR      'H'
 %define STAGE2_FAT32_NO_FILE         'I'
 %define STAGE2_FAT32_END_OF_CHAIN    'J'
-%define STAGE2_ERROR_RESERVED_K      'K'
+%define STAGE2_FAT32_NCLUS_CFDIVZ    'K'
-%define STAGE2_ERROR_RESERVED_L      'L'
+%define STAGE2_FAT32_CLS2LBA_CF      'L'
-%define STAGE2_ERROR_RESERVED_M      'M'
+%define STAGE2_FAT32_INIT_CF         'M'
 %define STAGE2_ERROR_RESERVED_N      'N'
 %define STAGE2_ERROR_RESERVED_O      'O'
 %define STAGE2_ERROR_RESERVED_P      'P'
@@ -71,30 +72,12 @@
 %define STAGE2_ERROR_RESERVED_T      'T'
 %define STAGE2_ERROR_RESERVED_U      'U'
 %define STAGE2_ERROR_RESERVED_V      'V'
 %define STAGE2_ERROR_RESERVED_W      'W'
 %define STAGE2_ERROR_RESERVED_X      'X'
 %define STAGE2_ERROR_RESERVED_Y      'Y'
 %define STAGE2_ERROR_RESERVED_Z      'Z'
 ; for development only, specific errors should be above.
 %define STEVIA_DEBUG_OK      'W'
 %define STEVIA_DEBUG_ERR      'X'
 %define STEVIA_DEBUG_UNIMPLEMENTED      'Y'
 %define STEVIA_DEBUG_HALT      'Z'
-%macro ERROR 1
+%endif
-    mov al, %1
+%define __INC_ERROR_CODES
    jmp error
 %endmacro
 ; pass error as ascii character in al, errors a-zA-Z or 0-9
 error:
    ; color 0x4F is white on red
    ; fs = 0xb800 => fs:0x0000 = 0xb8000
    mov dx, 0xB800
    mov fs, dx
    ; the characters are two bytes in the order of 0xb8000: byte c, byte attribute
    ; since x86 is le, we store the attribute in the MSB of dx
    mov dh, 0x4F
    mov dl, al
    mov word [fs:0x0000], dx
 .stop:
    hlt
    jmp short error.stop
--- a/include/fat32/FAT32_SYS.inc
+++ b/include/fat32/FAT32_SYS.inc
@@ -0,0 +1,323 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_FAT32_SYS
 %include "partition_table.inc"
 %include "fat32/bpb_offset_bx.inc"
 %include "fat32/fat32_structures.inc"
 ALIGN 4, db 0x90
 InitFATDriver:
    __CDECL16_ENTRY
 .func:
    mov ax, FAT32_State_t_size
    push ax                     ; length of fat32_state structure
    xor ax, ax
    push ax                     ; init fat32_state with zero
    mov ax, fat32_state
    push ax                     ; address of structure
    call kmemset
    sub sp, 0x6
 .calc_active_part:
    mov ax, word [partition_offset]            
    mov dx, partition_table
    add dx, ax                                                           ; dx points to the partition that was booted from
    mov bx, dx                                                           ; set bx, should point at our partition
    mov eax, dword [bx + PartEntry_t.lba_start]
    mov dword [fat32_state + FAT32_State_t.active_drive_lba_32], eax
 .calc_first_fat:
    movzx eax,  word [fat32_bpb + FAT32_bpb_t.reserved_sectors_16]        ; first fat from start of partition
    add   eax, dword [fat32_state + FAT32_State_t.active_drive_lba_32]    ; calculate offset from start of drive
    mov dword [fat32_state + FAT32_State_t.first_fat_sector_32], eax
 .calc_total_fat:
    mov ebx,  dword [fat32_ebpb + FAT32_ebpb_t.sectors_per_fat_32]
    movzx eax, byte [fat32_bpb + FAT32_bpb_t.fat_count_8]
    mul ebx                                                                ; result in EDX:EAX, CF set on > 32bit return value
    jc InitFATDriver.error                                                 ; as a catch for unhandled overflow, just error if value is greater than 32bits
    mov dword [fat32_state + FAT32_State_t.fat_size_32], eax
 .calc_first_data:
    mov edx, dword [fat32_state + FAT32_State_t.first_fat_sector_32]
    add eax, edx
    mov dword [fat32_state + FAT32_State_t.first_data_sector_32], eax
 .get_first_root_dir:
    mov eax, [fat32_ebpb + FAT32_ebpb_t.root_dir_cluster_32]
    mov dword [fat32_state + FAT32_State_t.first_root_dir_sector_32], eax   ; this only works when 1 cluster = 1 sector
    mov dword [fat32_state + FAT32_State_t.active_dir_cluster_32], eax
 .endp:
    __CDECL16_EXIT
    ret
 .error:
    ERROR STAGE2_FAT32_INIT_CF
 ; this involves using the low memory buffer for the bios call and moving the file sector by sector to high memory
 ;
 ; SFN is a 8.3 file name, all uppercase, and padded with spaces
 ; do not add a null byte to the end of the string
 ; eg. kernel.bin == "KERNEL  BIN"
 ;
 ; returns first cluster of file if found
 ; halts/errors if file is not found
 ; uint32_t SearchFATDIR(uint8_t* SFN);
 ALIGN 4, db 0x90
 SearchFATDIR:
    __CDECL16_ENTRY
 .file_lookup:
    print_string SearchFATDIR_INFO_cstr
    .load_first_dir:
        mov eax, dword [fat32_state + FAT32_State_t.active_dir_cluster_32]
        push dword eax          ; cluster
        mov ax, dir_buffer
        push ax                 ; offset
        xor ax, ax
        push ax                 ; segment
        call ReadFATCluster     ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
        add sp, 0x8
        mov si, dir_buffer
        jmp SearchFATDIR.empty_dir_entry
    .load_next_dir:
        ; if eax >= 0x0FFFFFF8 then there are no more clusters (end of chain)
        ; if eax == 0x0FFFFFF7 then this is a cluster that is marked as bad
        mov eax, dword [fat32_state + FAT32_State_t.active_dir_cluster_32]
        push dword eax
        call NextCluster        ; uint32_t NextCluster(uint32_t active_cluster);
        add sp, 0x4
        cmp eax, 0x0fff_fff7
        ;je SearchFATDIR.bad_cluster            ; TODO: Implement Bad cluster checks
        jb SearchFATDIR.load_next_dir_next_OK
        ERROR STAGE2_FAT32_END_OF_CHAIN
    .load_next_dir_next_OK:
        ; load 512 bytes of directory entries from data sector
        mov eax, [fat32_state + FAT32_State_t.active_dir_cluster_32]
        push dword eax          ; cluster
        mov ax, dir_buffer    
        push ax                 ; offset
        xor ax, ax
        push ax                 ; segment
        call ReadFATCluster     ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
        sub sp, 0x8
    .empty_dir_entry:
        ; check for 0x0 in first byte, if true then there are no more files
        ; if true we did not find the file, we should error here
        cmp byte [si], 0
        jne SearchFATDIR.unused_dir_entry
        ERROR STAGE2_FAT32_NO_FILE
    .unused_dir_entry:
        ; check for 0xe5 and 0x05 in first byte, if true then this entry is unused, but it is not the last entry.
        cmp byte [si], 0xe5
        je SearchFATDIR.next_entry
        cmp byte [si], 0x05
        je SearchFATDIR.next_entry
        jmp SearchFATDIR.parse_dir
    .next_entry:
        ; increment offset by 32 bytes to read the next entry in this set of dir entries
        ; if we are at the end of the buffer, then load the next buffer
        add si, 0x20        ; 32 bytes
        mov ax, dir_buffer
        add ax, 0x1FF       ; 512 - 1 bytes
        cmp si, ax
        jae SearchFATDIR.load_next_dir
        jmp SearchFATDIR.empty_dir_entry
    .parse_dir:
        print_string MaybeFound_Boot_INFO_cstr
        .lfn_check:
            ; check for ATTR_READ_ONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME_ID  (0x0F) in offset 11
            ; TODO: going to skip LFN for now, since all valid volumes will have SFN's
            cmp byte [si+11], 0x0F
            je SearchFATDIR.next_entry
        .sfn_file_name_check:
            push si
            push di
            mov cx, 0xA                     ; max of 11 filename length of 11 characters
            ; si points to the start of the current directory entry
            mov di, BootTarget_str          ; current memory location (8.3 name is at offset 0)
            repe cmpsb                      ; compare the strings
            pop di
            pop si
            jne SearchFATDIR.next_entry
            .sfn_entry_found:
            mov ax, [si + FAT32_SFN_t.cluster_16_high]
            shl eax, 16
            mov ax, [si + FAT32_SFN_t.cluster_16_low]
            ; eax == first cluster of file
 .endp:
    __CDECL16_EXIT
    ret
 ; BUG: this function needs review
 ; uint32_t NextCluster(uint32_t active_cluster);
 ; if eax >= 0x0FFFFFF8 then there are no more clusters (end of chain)
 ; if eax == 0x0FFFFFF7 then this is a cluster that is marked as bad
 ALIGN 4, db 0x90
 NextCluster:
    __CDECL16_ENTRY
 .func:
    print_string NextFATCluster_INFO_cstr
    mov edx, dword [bp + 4]
    mov si, fat32_nc_data                        ; instead of push/pop and moving the data back
    mov di, fat32_bpb                            ; load si & di then use xchg
 .calc_offset:
 ; fat_offset = active_cluster * 4
    mov eax, 4
    mul edx                                      
    jc NextCluster.error_cfdivz
    mov dword [si + FAT32_NextClusterData_t.fat_offset], eax        ; move lower 32 bits to fat offset
 .calc_fat_sector:
 ; fat_sector = first_fat_sector + (fat_offset / sector_size)
 ; entry_offset = fat_offset % sector_size
    mov edx, 0xffff_0000
    and edx, eax
    shr edx, 16
    xchg si, di         ; switch to fat32_bpb in si
    mov cx, word [si + FAT32_bpb_t.bytes_per_sector_16]
    xchg si, di
    cmp edx, 0
    je NextCluster.error_cfdivz
    div cx              ; DX:AX / cx = fat_sector - first_fat_sector in AX
                        ; DX = remainder (fat_offset mod sector_size)
    mov ecx, 0x0000_ffff
    and edx, ecx
    mov dword [si + FAT32_NextClusterData_t.entry_offset], edx
    xchg si, di         ; switch to fat32_bpb in si
    mov ecx, dword [si + FAT32_State_t.first_fat_sector_32]
    xchg si, di
    mov edx, 0x0000ffff
    and eax, edx
    add eax, ecx        ; fat_sector + first_fat_sector
    mov dword [si + FAT32_NextClusterData_t.fat_sector], eax
 .load_fat_table:
    xor ax, ax
    mov al, byte [boot_drive]
    push ax
    mov ax, 0x1
    push ax
    ; load correct fat
    mov eax, dword [si + FAT32_NextClusterData_t.fat_sector]
    push dword eax
    mov ax, fat_buffer
    push ax
    xor ax, ax
    push ax
    call read_disk_raw  
    add sp, 0xC
    ; uint8_t read_stage2_raw(uint16_t buf_segment, uint16_t buf_offset, 
 ;                         uint32_t lba,
 ;                         uint16_t count, uint16_t drive_num)
 .read_cluster:
 ; next_cluster = fat_buffer[entry_offset]
    mov ebx, dword [si + FAT32_NextClusterData_t.entry_offset]
    mov si, fat_buffer
    mov eax, dword [bx+si+0]
 .endp:
    __CDECL16_EXIT
    ret
 .error_cfdivz:
    ERROR STAGE2_FAT32_NCLUS_CFDIVZ
 ; uint32_t ClusterToLBA(uint32_t cluster)
 ALIGN 4, db 0x90
 ClusterToLBA:
    __CDECL16_ENTRY
 .func:
    mov dword eax, [bp + 4]
    sub eax, 2
    movzx edx, byte [fat32_bpb + FAT32_bpb_t.sectors_per_cluster_8]
    mul edx
    jc ClusterToLBA.error
    add eax, dword [fat32_state + FAT32_State_t.first_data_sector_32]
    ; eax contains the LBA now
 .endp:
    __CDECL16_EXIT
    ret
 .error:
    ERROR STAGE2_FAT32_CLS2LBA_CF
 ; bp - 2 - byte boot_drive
 ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
 ALIGN 4, db 0x90
 ReadFATCluster:
    __CDECL16_ENTRY
 .func:
    print_string ReadFATCluster_INFO_cstr
    xor ax, ax
    mov al, byte [boot_drive]
    push ax
    mov ax, 0x1                         ; count = 1
    push ax
    mov eax, dword [bp + 8]
    push dword eax
    call ClusterToLBA
    add sp, 0x4
    ; eax contains the LBA now
    push dword eax                      ; lba = ClusterToLBA(..)
    mov ax, fat_buffer                  ; offset = fat_buffer (in mem.inc)
    push ax
    xor ax, ax                          ; segment = 0x0000, our buffer is in the first 64 KiB
    push ax
 ; uint8_t read_stage2_raw(uint16_t buf_segment, uint16_t buf_offset, 
 ;                         uint32_t lba,
 ;                         uint16_t count, uint16_t drive_num)
    call read_disk_raw  
    add sp, 0xC
 .endp:
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_FAT32_SYS
--- a/include/fat32/bpb_offset_bx.inc
+++ b/include/fat32/bpb_offset_bx.inc
@@ -1,4 +1,4 @@
-; Copyright (c) 2023 Elaina Claus
+; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
@@ -18,6 +18,7 @@
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_BPD_OFFSET_BX
 ; BPB Information
 ; Off.  Hex Off. Size   Description
@@ -88,4 +89,7 @@
 %define bsVolumeSerial      bx+0x43
 %define bsVolumeLabel       bx+0x47
 %define bsSystemIdent       bx+0x52
-;-- End EBPB
+;-- End EBPB
 %endif
 %define __INC_BPD_OFFSET_BX
--- a/include/fat32/fat32_structures.inc
+++ b/include/fat32/fat32_structures.inc
@@ -18,6 +18,7 @@
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_FAT32_STRUCT
 ; ## FAT32 Info ##
 ;   total_sectors = bsSectorsHuge
@@ -62,6 +63,7 @@
 ;                           resulting in a value which does not fit in the Number of Sectors entry at 0x13. 
 struc FAT32_bpb_t
    .reserved_init             resb 3
    .ident_8                   resb 8
    .bytes_per_sector_16       resb 2
    .sectors_per_cluster_8     resb 1
@@ -230,4 +232,5 @@ endstruc
 ; LFN == RO | HIDDEN | SYSTEM | VOLID == 0x0F
 %define FAT32_ATTR_LFN          0x0F
-
+%endif
 %define __INC_FAT32_STRUCT
--- a/include/memory.inc
+++ b/include/memory.inc
@@ -1,213 +0,0 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 ; ## Generic Low mem map (from osdev wiki) ##
 ; start 	        end 	    size 	        type 	                    description
 ; Low Memory (the first MiB)
 ; 0x00000000 	0x000003FF 	1 KiB 	        RAM - partially unusable  	Real Mode IVT (Interrupt Vector Table)
 ; 0x00000400 	0x000004FF 	256 bytes 	    RAM - partially unusable 	BDA (BIOS data area)
 ; 0x00000500 	0x00007BFF 	almost 30 KiB 	RAM - free for use 	        Conventional memory
 ; 0x00007C00  	0x00007DFF 	512 bytes 	    RAM - partially unusable  	OS BootSector
 ; 0x00007E00 	0x0007FFFF 	480.5 KiB 	    RAM - free for use 	        Conventional memory
 ; 0x00080000 	0x0009FFFF 	128 KiB 	    RAM - partially unusable 	EBDA (Extended BIOS Data Area)
 ; 0x000A0000 	0x000FFFFF 	384 KiB 	    various (unusable) 	        Video memory, ROM Area
 ; ## A rough overview of high mem ##
 ; Idealy this needs to be probed with the E820 functions
 ; # Start                   # End           # size                      # description
 ;
 ; 0x00100000 	            0x00EFFFFF 	    0x00E00000 (14 MiB) 	    RAM -- free for use (if it exists) 	Extended memory
 ; 0x00F00000 	            0x00FFFFFF 	    0x00100000 (1 MiB) 	        Possible memory mapped hardware 	ISA Memory Hole 15-16MB
 ; 0x01000000 	            ???????? 	    ??? (whatever exists) 	    RAM -- free for use 	            More Extended memory
 ; 0xC0000000 (sometimes) 	0xFFFFFFFF 	    0x40000000 (1 GiB) 	 	    Memory mapped PCI devices, PnP NVRAM?, IO APIC/s, local APIC/s, BIOS, ...
 ; 0x0000000100000000  	    ???	            ??? (whatever exists) 	    RAM -- free for use (PAE/64bit)/More Extended memory
 ; ???????????????? 	        ??? 	        ??? 	                    Potentially usable for memory mapped PCI devices in modern hardware (but typically not, due to backward compatibility) 
 ; 0x2700 -> 0x28FF
 %define disk_buffer           0x2700
 ; 0x2900 -> 0x2AFF
 %define fat_buffer            0x2900
 ; 0x2B00 -> 0x2CFF
 %define dir_buffer            0x2B00
 ; copy of partition table, 72 bytes
 %define partition_table       0x3000
 %define partition_table_SIZE  72
 ; copy of FAT32 BPB, 33 bytes (+1 to the next value to align to uint16_t)
 ;0x3048
 %define fat32_bpb             0x3050
 %define fat32_bpb_SIZE        33
 ; copy of FAT32 EBPB, 54 bytes
 ;0x306A
 %define fat32_ebpb            0x3070
 %define fat32_ebpb_SIZE       54
 ; FAT32 FSInfo, 512 bytes
 ;0x30A2
 %define fat32_fsinfo          0x30B0
 %define fat32_fsinfo_SIZE     512
 ; some stored state for the fat32 driver
 ;0x32A2
 %define fat32_state           0x32B0
 %define fat32_state_SIZE      32
 ; next free space is 0x32D0
 %define fat32_nc_data         0x32D0
 %define fat32_nc_data_size    16
 ; lba_packet for raw_disk_read
 %define lba_packet            0x4000
 %define BIOSMemoryMap         0x4200
 %define SteviaInfo            0x4400
 ; High memory addresses for loading kernel (for use with unreal mode and 32bit override)
 ; file load buffer at 16MB
 %define HMEM_load_buffer      0x1000000
 ;PhysicalAddress = Segment * 16 + Offset
 %define SEG_TO_LINEAR(s,o) ((s << 4) + o)
 ; Offset = physical / (Segment * 16)
 %define LINEAR_TO_OFFSET(p,s) ((p / (s << 4)))
 ; Seg = (physical - offset) / 16
 %define LINEAR_TO_SEGMENT(p,o) ((p - o) >> 4)
 ; create normalized linear addres from seg:off (16:4)
 ; Segement = linear >> 4 (top 16 bits)
 ; offset = linear & 0x0F (low 4 bits)
 ; 20 bytes, passed to loaded kernel
 struc SteviaInfoStruct_t
    .MemoryMapPtr      resd 1
    .MemoryMapEntries  resd 1
    .BPBDataPtr        resd 1
    .EBPBDataPtr       resd 1
 endstruc
 ; Address Range Descriptor Structure
 ;
 ; Offset in Bytes		Name		Description
 ;	0	    BaseAddrLow		u32 - Low 32 Bits of Base Address
 ;	4	    BaseAddrHigh	u32 - High 32 Bits of Base Address
 ;	8	    LengthLow		u32 - Low 32 Bits of Length in Bytes
 ;	12	    LengthHigh		u32 - High 32 Bits of Length in Bytes
 ;	16	    Type		    u32 - Address type of  this range.
 ;   20      ExtType         u32 -  ACPI 3.0 extended type
 struc AddressRangeDescStruct_t
    .BaseAddrLow    resd 1
    .BaseAddrHigh   resd 1
    .LengthLow      resd 1
    .LengthHigh     resd 1
    .Type           resd 1
    .ExtType        resd 1
 endstruc
 ; moves argument into eax then pushes lower 16bits then upper 16 bits of of argument to stack
 ; eax is clobbered
 %macro PUSH_DWORD 1
    mov eax, %1
    push ax
    shr eax, 16
    push ax
 %endmacro
 ; same as PUSH_DWORD except no arguments, pushes EAX directly
 %macro PUSH_DWORD_EAX 0
    push ax
    shr eax, 16
    push ax
 %endmacro
 ; pops upper 16bits then lower 16bits into eax
 ; eax is clobbered
 %macro POP_DWORD_EAX 0
    xor eax, eax
    pop ax
    shl eax, 16
    pop ax
 %endmacro
 ; moves data on stack referenced by bp to eax
 ; stack must be organized as follows (tl;dr push lower 16bits first ie. PUSH_DWORD macro)
 ; MOV_DWORD_EAX 2
 ; STACK TOP (0x0)
 ;   upper_uint16  [bp-4]
 ;   lower_uint16 [bp-2]
 ;   --- [bp] ---
 ;   ...
 ; STACK BOTTOM
 ;
 ; first argument == starting offset from bp for lower 16bits
 %macro MOV_DWORD_EAX 1
    mov ax, [bp-(%1+2)]
    shl eax, 16
    mov ax, [bp-%1]
    ; eax contains dword from stack
 %endmacro
 %macro DEBUG_HCF 0
    DEBUG_LOOP:
        hlt
        jmp short DEBUG_LOOP
 %endmacro
 ; uint8_t* kmemset(void* dest, uint8_t val, size_t len);
 kmemset:
    push    di             ; function uses di, so save it.
    mov     cx, [bp - 2]   ; size_t len
    mov     al, [bp - 4]   ; uint8_t val
    mov     di, [bp - 6]   ; void * ptr
    cld
    rep     stosb 
 .endf:
    mov     ax, [bp - 6]  ; return pointer to dest
    pop     di            ; restore di
    ret
 ; uint8_t* kmemset(uint8_t* dest, uint8_t* src, size_t len);
 ; not overlap safe
 kmemcpy:
    push di
    push si                 ; di, si are callee save
    mov cx, [bp - 2]        ; length
    mov si, [bp - 4]        ; source
    mov di, [bp - 6]        ; dest
    cld                     ; ensure we are incrementing
    rep movsb
 .endf:
    mov ax, [bp - 6]        ; return pointer to dest
    pop si
    pop di
    ret
--- a/include/partition_table.inc
+++ b/include/partition_table.inc
@@ -1,4 +1,4 @@
-; Copyright (c) 2023 Elaina Claus
+; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
@@ -18,6 +18,8 @@
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_PART_TABLE
 ; Partition table entry format
 ; Off.  Size.       Description
 ;0x00 	  1 	Drive attributes (bit 7 set = active or bootable)
@@ -32,32 +34,18 @@ struc PartEntry_t
    .chs_start  resb 3
    .part_type  resb 1
    .chs_end    resb 3
-    .lba_start  resb 4
+    .lba_start  resd 1
-    .lba_length resb 4
+    .lba_length resd 1
 endstruc
 struc PartTable_t
-    .partition1 resb 16
+    .signature resb 4
-    .partition2 resb 16
+    .reserved  resb 2
-    .partition3 resb 16
+    .partition1 resb PartEntry_t_size
-    .partition4 resb 16
+    .partition2 resb PartEntry_t_size
    .partition3 resb PartEntry_t_size
    .partition4 resb PartEntry_t_size
 endstruc
-
+%endif
-;Offset	Size	    Description
+%define __INC_PART_TABLE
 ; 0	    1	    size of packet (16 bytes)
 ; 1	    1	    always 0
 ; 2	    2	    number of sectors to transfer (max 127 on some BIOSes)
 ; 4	    4	    transfer buffer (0xFFFF:0xFFFF)
 ; 8	    4	    lower 32-bits of starting 48-bit LBA
 ; 12	4	    upper 32-bits of starting 48-bit LBA
 ; needs to be aligned to a uint32_t
 struc LBAPkt_t
    .size        resb 1
    .res0        resb 1
    .xfer_size   resw 1
    .offset      resw 1
    .segment     resw 1
    .lower_lba   resd 1
    .upper_lba   resd 1
 endstruc
--- a/include/util/bochs_magic.inc
+++ b/include/util/bochs_magic.inc
@@ -0,0 +1,56 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_BOCHS_DEBUG_MAGIC
 ; for things like the error printer, opperate differently when we are targeting a dev (bochs) build
 %define __STEVIA_DEV_DEBUG
 ; port_e9_hack: enabled=1 needs to be set in bochsrc.txt/bxrc
 ;
 %ifnmacro __BOCHS_PRINTC
    %macro __BOCHS_PRINTC 1
        mov al, %1
        out 0xe9, byte al
    %endmacro
 %endif
 ;
 ; port_e9_hack: enabled=1 needs to be set in bochsrc.txt/bxrc
 ;
 %ifnmacro __BOCHS_BREAK
    %macro __BOCHS_BREAK 0
        push ax
        mov ax, 0x8A00
        out 0x8A00, word ax
        pop ax
    %endmacro
 %endif
 ;
 ; magic_break: enabled=1 needs to be set in bochsrc.txt/bxrc
 ;
 %ifnmacro __BOCHS_MAGIC_DEBUG
    %macro __BOCHS_MAGIC_DEBUG 0
        xchg bx, bx
    %endmacro
 %endif
 %define __INC_BOCHS_DEBUG_MAGIC
 %endif
--- a/include/util/error_func.nasm
+++ b/include/util/error_func.nasm
@@ -0,0 +1,50 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_ERROR_FUNC
 %macro ERROR 1
    %ifdef __STEVIA_DEV_DEBUG
    __BOCHS_MAGIC_DEBUG
    %endif
    mov al, %1           ; al = 1 byte error code mapped to ascii values
    jmp error
 %endmacro
 ; pass error as ascii character in al, errors a-zA-Z or 0-9
 ALIGN 4, db 0x90
 error:
    cmp al, STEVIA_DEBUG_OK
    jge short .debug            ; the 'letter >= W' (W, X, Y, Z) are used as special debug codes
    mov ah, 0x4F                ; color 0x4F is white text/red background
    jmp short .print
 .debug:
    mov ah, 0x5F                ; debug case is white text/purple background
 .print:
    mov dx, 0xB800
    mov gs, dx                  
    mov word [gs:0x0000], ax    ; 0xB8000 = video memory
 .halt:
    cli
    hlt
    jmp short .halt
 %endif
 %define __INC_ERROR_FUNC
--- a/include/util/kmem_func.nasm
+++ b/include/util/kmem_func.nasm
@@ -0,0 +1,58 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_KMEM_FUNC
 %include 'cdecl16.inc'
 ; uint8_t* kmemset_byte(void* dst, uint8_t val, uint16_t len);
 ALIGN 4, db 0x90
 kmemset:
    __CDECL16_ENTRY
 .func:
    mov     cx, [bp + 8]   ; size_t len
    mov     al, [bp + 6]   ; uint8_t val
    mov     di, [bp + 4]   ; void * dst
    cld
    rep     stosb
    mov     ax, di         ; return pointer to dest
 .endp:
    __CDECL16_EXIT
    ret
 ; uint8_t* kmemset(uint8_t* dest, uint8_t* src, uint8_t len);
 ; not overlap safe
 ALIGN 4, db 0x90
 kmemcpy:
    __CDECL16_ENTRY
 .func:
    mov cx, [bp + 8]        ; len
    mov si, [bp + 6]        ; src
    mov di, [bp + 4]        ; dest
    cld                     ; ensure we are incrementing
    rep movsb
    mov ax, di              ; return pointer to dest
 .endf:
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_KMEM_FUNC
--- a/include/util/kmemcpy5_func.nasm
+++ b/include/util/kmemcpy5_func.nasm
@@ -0,0 +1,53 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_KMEMCPY5_FUNC
 %include 'cdecl16.inc'
 ; uint8_t* kmemset(word dest_segment, word dest, word src_segment, word src, byte len);
 ; not overlap safe, only for
 ALIGN 4, db 0x90
 kmemcpy5:
    __CDECL16_ENTRY
    push ds
    push es
 .setup_segments:
    mov ax, [bp + 4]
    mov ds, ax              ; destination segment
    mov ax, [ bp + 8]
    mov es, ax              ; source segment
 .func:
    mov cx, [bp + 12]        ; len
    mov si, [bp + 10]        ; src
    mov di, [bp + 6]        ; dest
    cld                     ; ensure we are incrementing
    rep movsb               ; move ds:si -> es:di
    mov ax, di              ; return pointer to dest
 .restore_segments:
    pop es
    pop ds
 .endf:
    __CDECL16_EXIT
    ret
 %define __INC_KMEMCPY5_FUNC
 %endif
--- a/include/util/kmemset4_func.nasm
+++ b/include/util/kmemset4_func.nasm
@@ -0,0 +1,47 @@
 ; Copyright (c) 2024 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 %ifndef __INC_KMEMSET4_FUNC
 %include 'cdecl16.inc'
 ; word kmemset_byte(word segment, word dst, byte val, word len);
 ALIGN 4, db 0x90
 kmemset4:
    __CDECL16_ENTRY
 .setup_segment:
    push es
    mov ax, [bp + 4]
    mov es, ax
 .func:
    mov     cx, [bp + 10]       ; size_t len
    mov     al, [bp + 8]        ; uint8_t val
    mov     di, [bp + 6]        ; word dst
    cld
    rep     stosb               ; move al -> es:di
    mov     ax, di              ; return pointer to dest
 .restore_segments:
    pop es
 .endf:
    __CDECL16_EXIT
    ret
 %endif
 %define __INC_KMEMSET4_FUNC
--- a/scripts/create-disk.sh
+++ b/scripts/create-disk.sh
@@ -21,25 +21,40 @@
 # SOFTWARE.
 if ! [ $(id -u) = 0 ]; then
-   echo "Script must be run as root!"
+   echo "Script must be run as root!" >&2
   exit 1
 fi
 # paths to bootcode
 mbr_file=build/mbr.bin
 vbr_file=build/vbr.bin
 stage2_file=build/stage2.bin
-boottest_file=build/BOOT_386.bin
+boottest_file=build/BOOTi686.bin
 # Disk creation options
 mount_point=/tmp/stevia_disk
 disk_tmp_file=/tmp/disk.img
 disk_file_final=./disk.img.gz
-if ! [ -e disk.img ]; then
+# $disk_sector_size * $disk_size = total bytes, default is 256MiB
-    # create raw disk image with 128MiB of space
+disk_size=(524288 * 2)
-    dd if=/dev/zero of=disk.img bs=512 count=262144
+disk_sector_size=512
 if ! [ -e $disk_tmp_file ]; then
    # create raw disk image
    if ! dd if=/dev/zero of=$disk_tmp_file bs=$disk_sector_size count=$disk_size; then
        echo "Failed creating blank disk image." >&2
        exit 1
    fi
    sync
 else
    echo "Removing old disk image..."
-    rm -rfv disk.img
+    rm -rfv $disk_tmp_file
-    dd if=/dev/zero of=disk.img bs=512 count=262144
+    if ! dd if=/dev/zero of=$disk_tmp_file bs=$disk_sector_size count=$disk_size; then
        echo "Failed creating blank disk image." >&2
        exit 1
    fi
    sync
 fi
@@ -47,33 +62,68 @@ if [[ "$OSTYPE" == "linux-gnu"* ]]; then
        if [ -e $mbr_file ] && [ -e $vbr_file ]; then
        # get next loop device and mount it
        ld=$(losetup -f)
-        losetup -b 512 $ld disk.img
+        losetup -P -b 512 $ld $disk_tmp_file
        # create a DOS disk, with 1 FAT32 partition that is bootable, part1 starts at sector 2048
        sfdisk $ld < scripts/loop_setup.sfdisk
-        # partprobe the image
+        # get first partition, this is sloppy might need to review this...
        partprobe $ld
        # get first partition
        firstpart=$(lsblk -ilp -o NAME $ld | tr '\n' ' ' | awk '{print $3}')
-        mkfs.vfat -v -F32 $firstpart
+        mkfs.fat -v -F32 -s 1 -n 'STEVIAFS' $firstpart
        #
        # MBR setup
        #
        # copy MBR while preserving partition table
-        dd if=$mbr_file of=$ld bs=1 count=440
+        if ! dd if=$mbr_file of=$ld bs=1 count=440; then
            echo "Failed to write MBR to disk. (part 1)" >&2
            exit 1
        fi
        # copy MBR 0xAA55
-        dd if=$mbr_file of=$ld bs=1 seek=510 skip=510 count=2
+        if ! dd if=$mbr_file of=$ld bs=1 seek=510 skip=510 count=2; then
            echo "Failed to write MBR to disk. (part 2)" >&2
            exit 1
        fi
        #
        # VBR Setup & backup VBR
        # 
        # copy VBR to partition 1 while preserving partition information
        # copy jmp short entry; nop
-        dd if=$vbr_file of=$firstpart bs=1 count=3
+        if ! dd if=$vbr_file of=$firstpart bs=1 count=3; then
            echo "Failed to write VBR to disk. (part 1)" >&2
            exit 1
        fi
        # copy bootcode
-        dd if=$vbr_file of=$firstpart bs=1 seek=90 skip=90 count=420
+        if ! dd if=$vbr_file of=$firstpart bs=1 seek=90 skip=90 count=420; then
            echo "Failed to write VBR to disk. (part 2)" >&2
            exit 1
        fi
        # copy 0xAA55
-        dd if=$vbr_file of=$firstpart bs=1 seek=510 skip=510 count=2
+        if ! dd if=$vbr_file of=$firstpart bs=1 seek=510 skip=510 count=2; then
            echo "Failed to write VBR to disk. (part 3)" >&2
            exit 1
        fi
        # write backup VBR
        if ! dd if=$firstpart of=$firstpart bs=$disk_sector_size count=1 seek=6; then
            echo "Failed to copy VBR (sector 1) to backup VBR." >&2
            exit 1
        fi
        #
        # Stage2 Setup
        #
        #stage2 to sectors 1-64
-        dd if=$stage2_file of=$ld bs=512 seek=1
+        if ! dd if=$stage2_file of=$ld bs=$disk_sector_size seek=1; then
            echo "Failed to write Stage2 to disk." >&2
            exit 1
        fi
        # copy boot32 boot test file to disk image
        if ! [ -e $mount_point ]; then
@@ -81,25 +131,39 @@ if [[ "$OSTYPE" == "linux-gnu"* ]]; then
        fi
        mount $firstpart $mount_point
-        if [ -e $boottest_file ]; then
+        # ensure mountpoint is actually a mountpoint
-            cp -v $boottest_file $mount_point
+        if ! mountpoint -q $mount_point; then
-        else
+            echo "Failed to mount partition at $mount_point." >&2
-            echo "unable to find boot32.bin!"
+            exit 1
            exit 3
        fi
        # copy kernel to filesystem 
        if [ -e $boottest_file ]; then
            cp -v $boottest_file $mount_point/BOOT.BIN
        else
            echo "Failed to write $boottest_file to disk image" >&2
            exit 1
        fi
        #
        # Final Cleanup
        #
        # detach loop device
        umount $mount_point
        sync
        sleep 1
        losetup -d $ld
        # chown to the real user to prevent issues with reading/writing the file later
-        SUDOUSER=$(logname)
+        # BUG: ${logname}:$(id $(logname -g)) doesn't work right on WSL because of runlevel hacks in WSL
-        chown --from=root:root ${SUDOUSER}:$(id $SUDOUSER -g) disk.img
+        # BUG: https://github.com/microsoft/WSL/issues/1761
        # as a work around I'll just reference LICENSE.md...WHICH SHOULD ALWAYS BE THERE 👀
        chown --from=root:root --reference=LICENSE.md $disk_tmp_file
    else
-        echo "unable to find MBR/VBR binaries!"
+        echo "unable to find MBR/VBR binaries!" >&2
-        exit 2
+        exit 1
    fi
 # requires util-linux from homebrew
 elif [[ "$OSTYPE" == "darwin"* ]]; then
@@ -159,7 +223,7 @@ elif [[ "$OSTYPE" == "darwin"* ]]; then
        dd if=$vbr_file of=/dev/$firstpart bs=1 seek=510 skip=510 count=2 conv=sync
        #stage2 to sectors 1-64
-        dd if=$stage2_file of=$ld_path bs=512 seek=1 conv=sync
+        dd if=$stage2_file of=$ld_path bs=$disk_sector_size seek=1 conv=sync
        #sync pending dd stuff
        sync
@@ -189,7 +253,7 @@ elif [[ "$OSTYPE" == "darwin"* ]]; then
        # chown to the real user to prevent issues with reading/writing the file later
        SUDOUSER=$(logname)
        chown ${SUDOUSER}:staff disk.img
-
+        gzip -9kc $disk_tmp_file > $disk_file_final
    else
        echo "unable to find MBR/VBR binaries!"
        exit 2
--- a/scripts/loop_setup.sfdisk
+++ b/scripts/loop_setup.sfdisk
@@ -1,4 +1,5 @@
 label: dos
 unit: sectors
 sector-size: 512
-start=        2048, type=b, bootable
+start=        2048, type=c, bootable
--- a/src/mbr/mbr.nasm
+++ b/src/mbr/mbr.nasm
@@ -0,0 +1,205 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 16]
 [ORG 0x8C00]
 [CPU KATMAI]
 [WARNING -reloc-abs-byte]
 [WARNING -reloc-abs-word]                   ; Yes, we use absolute addresses. surpress these warnings.
 [map all mbr.map]
 %define __STEVIA_MBR
 jmp short (init - $$)
 nop
 ; ###############
 ; Headers/Includes/Definitions
 ; ###############
 %include "util/bochs_magic.inc"
 %include "cdecl16.inc"
 %include "entry.inc"
 %include "config.inc"
 %include "error_codes.inc"
 %include "partition_table.inc"
 %include "fat32/fat32_structures.inc"
 %undef __STEVIA_DEV_DEBUG
 ALIGN 4
 init:
    cli                             ; We do not want to be interrupted
    xor ax, ax                      
    mov ds, ax                      ; Set segment registers to 0x0000
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax                      ; Set Stack Segment to 0
    mov sp, end_bss                 ; Setup stack
    mov bp, sp                      ; base ptr = stack ptr
    ; Zero BSS section
    mov cx, (end_bss - begin_bss)     ; count = bss length                    
    mov ax, begin_bss
    mov di, ax                        ; es:di is dest
    xor ax, ax
    cld
    rep stosb                         ; zero bss section
    sub sp, 0x20                    ; local varible space
    push bp                         ; setup top of stack frame
    xor cx, cx
    mov ch, 0x02                    ; 0x0200 in cx
    mov si, 0x7C00                  ; Current MBR Address (loaded here by BIOS)
    mov di, MBR_ENTRY               ; New MBR Address (our new relocation address)
    rep movsb                       ; copy 512 bytes from 0x0000:7c00 to 0x0000:MBR_ENTRY (7A00 as of writing)
    sti
    jmp 0:main
 ; ###############
 ; Extra/Shared Functions
 ; ###############
 %include "util/kmem_func.nasm"
 %include "util/error_func.nasm"
 ;
 ; bp - 2 : uint8_t boot_drive
 ; bp - 4 : uint16_t part_offset
 ALIGN 4, db 0x90
 main:
    mov byte [bp - 2], dl            ; BIOS passes drive number in DL
    .check_disk:
        cmp byte [bp - 2], 0x80
        jae main.check_extentions
        ERROR MBR_ERROR_DISK_T_ERR
    .check_extentions:
        xor ax, ax
        mov ah, 0x41
        mov bx, 0x55AA
        mov dl, 0x80
        int 0x13
        jnc main.find_active
        ERROR MBR_ERROR_NO_INT32E                         ; no extended function support
    .find_active:
        mov bx, PartEntry1                      ; base = first partition
        mov cx, 4                               ; there are only 4 entries
    .find_active_L0:
        mov al, byte [bx + PartEntry_t.attributes]
        test al, 0x80                           ; 0x80 == 1000_0000b
        jnz main.active_found
        add bx, 0x10                            ; add 16 bytes to offset
        loop main.find_active_L0
        ERROR MBR_ERROR_NO_NO_BOOT_PART
    .active_found:
        mov ax, bx
        sub ax, DiskSig                         ; leaves us with the offset relative from start of table
                                                ; this gives us an offset from the begining of the partition table
        mov word [bp - 4], ax                   ; update part_offset
    .read_data:
        movzx ax, byte [bp - 2]
        push ax                                            ; drive_num
        mov ax, 0x1
        push ax                                            ; count
        mov dword eax, dword [bx + PartEntry_t.lba_start]
        push dword eax                                     ; lba
        mov ax, VBR_ENTRY
        push ax                                            ; offset = 0x7c00
        xor ax, ax
        push ax                                            ; segment = 0
        ; uint8_t read_stage2_raw(uint16_t buf_segment, uint16_t buf_offset, 
        ;                         uint32_t lba,
        ;                         uint16_t count, uint16_t drive_num)
        call read_disk_raw
        add sp, 0xC
    .goto_vbr:
        cmp word [VBR_ENTRY + 0x1FE], 0xAA55
        je main.sig_ok
        ERROR MBR_ERROR_NO_VBR_SIG                        ; no signature present
    .sig_ok:
        mov ax, PartTable_t_size                
        push ax
        mov ax, DiskSig                         ; start of partition table
        push ax
        mov ax, partition_table                 
        push ax
        call kmemcpy                            ; copy partition table to bss
        add sp, 0x6
        mov si, word [bp - 4]
        mov dl, byte [bp - 2]
        mov bx, partition_table
        jmp word 0x0000:VBR_ENTRY
 ; ###############
 ;
 ; BIOS Functions
 ;
 ; ###############
 %include 'BIOS/func/ext_read.nasm'
 %assign bytes_remaining (440 - ($ - $$))
 %warning MBR has bytes_remaining bytes remaining for code (MAX: 440 bytes)
 times ((512 - 72) - ($ - $$)) nop     ; Fill the rest of sector with nop
 DiskSig:
    times 4 db 0x00
 Reserved:
    dw 0x0000
 PartEntry1:
    times 16 db 0x00
 PartEntry2:
    times 16 db 0x00
 PartEntry3:
    times 16 db 0x00
 PartEntry4:
    times 16 db 0x00
 BootSig:
    dw 0xAA55                    ; Add boot signature at the end of bootloader
 section .bss follows=.text
 begin_bss:
 align 16, resb 1
 partition_table resb PartTable_t_size
 align 16, resb 1
 lba_packet resb LBAPkt_t_size
 align 512, resb 1
 stack_bottom resb 512                  ; 512 byte stack early on
 stack_top:
 mbr_redzone resb 32
 end_bss:
--- a/src/mbr/mbr.s
+++ b/src/mbr/mbr.s
@@ -1,244 +0,0 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 16]
 [ORG 0x7A00]
 [CPU KATMAI]
 jmp short init
 nop
 %include "entry.inc"
 init:
    cli                             ; We do not want to be interrupted
    xor ax, ax                      ; 0 AX
    mov ds, ax                      ; Set segment registers to 0
    mov es, ax                      ; *
    mov ss, ax                      ; Set Stack Segment to 0
    mov sp, STACK_START             
    mov ch, 0x01                    ; 256 WORDs in MBR (512 bytes), 0x0100 in cx
    mov si, 0x7C00                  ; Current MBR Address (loaded here by BIOS)
    mov di, MBR_ENTRY               ; New MBR Address (our new relocation address)
    rep movsw                       ; copy 512 bytes from 0x0000:7c00 to 0x0000:0600
    jmp 0:main
    nop
 %include "config.inc"
 %include "memory.inc"
 %include "partition_table.inc"
 %include "errors.inc"
 main:
    sti
    mov [boot_drive], dl            ; BIOS passes drive number in DL
    .check_disk:
        cmp dl, 0x80
        jae main.find_active
        ERROR MBR_ERROR_DISK_T_ERR
    .check_extentions:
        xor ax, ax
        mov bx, 0x55AA
        mov dl, byte [boot_drive]
        int 0x13
        jnc main.find_active
        ERROR MBR_ERROR_NO_INT32E                         ; no extended function support
    .find_active:
        mov bx, PartEntry1                      ; base = first partition
        mov cx, 4                               ; there are only 4 entries
    .find_active_L0:
        mov al, byte [bx + PartEntry_t.attributes]
        test al, 0x80                           ; 0x80 == 1000_0000b
        jnz main.active_found
        add bx, 0x10                            ; add 16 bytes to offset
        loop main.find_active_L0
        ERROR MBR_ERROR_NO_NO_BOOT_PART
    .active_found:
        mov ax, bx
        sub ax, DiskSig                         ; leaves us with the offset relative from start of table
                                                ; this gives us an offset from the begining of the partition table
        mov word [part_offset], ax              ; update part_offset
    .read_data:
        push bp
        mov bp, sp
        ;uint8_t read_disk_raw(size_t count, uint16_t buf_segment, uint16_t buf_offset, 
        ;                      uint16_t lower_lower_lba, uint16_t upper_lower_lba)
        mov eax, dword [bx + PartEntry_t.lba_start]
        ror eax, 16
        push ax
        ror eax, 16
        push ax         
        mov ax, VBR_ENTRY
        push ax
        xor ax, ax
        push ax        ; segment = 0  
        mov ax, 1
        push ax
        call read_disk_raw
        leave
        jnc main.goto_vbr
        ERROR MBR_ERROR_DISK_READ_ERR                     ; error in LBA read
    .goto_vbr:
        cmp word [VBR_ENTRY + 0x1FE], 0xAA55
        je main.sig_ok
        ERROR MBR_ERROR_NO_VBR_SIG                        ; no signature present
    .sig_ok:
        push bp
        mov bp, sp
        mov ax, partition_table_SIZE            ; 72 bytes of data
        push ax
        mov ax, DiskSig                         ; start of partition table
        push ax
        mov ax, partition_table                 ; defined in memory.inc
        push ax
        call kmemcpy                            ; copy partition table to memory
        leave
        xor ah, ah                              ; Set Video mode BIOS function
        mov al, 0x02                            ; 16 color 80x25 Text mode
        int 0x10                                ; Call video interrupt
        mov ah, 0x05                            ; Select active display page BIOS function
        xor al, al                              ; page 0
        int 0x10                                ; call video interrupt
        mov si, word [part_offset]
        mov dl, byte [boot_drive]
        jmp 0:0x7C00
 ; Wrapper for AH=0x42 INT13h (Extended Read)
 ;
 ; BIOS call details
 ; AH = 42h
 ; DL = drive number
 ; DS:SI -> disk address packet
 ;
 ; Return:
 ; CF clear if successful
 ; AH = 00h
 ; CF set on error
 ; AH = error code
 ; disk address packet's block count field set to number of blocks
 ; successfully transferred
 ;
 ;
 ; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint16_t lower_lower_lba, uint16_t upper_lower_lba)
 ; bp-0 = call frame
 ; bp-2 = upper_lower_lba
 ; bp-4 = lower_lower_lba
 ; bp-6 = offset
 ; bp-8 = segment
 ; bp-10 = count
 ; bp-12 = ret ptr
 read_disk_raw:
    push si
    ; uint8_t* kmemset(void* dest, uint8_t val, size_t len);                      
    push bp
    mov bp, sp
    mov ax, 0x10
    push ax             ; len = 16 bytes
    xor ax, ax
    push ax             ; val = 0
    mov ax, lba_packet
    push ax             ; dest = lba_packet address
    call kmemset
    leave
    mov byte [lba_packet + LBAPkt_t.size], 0x10
    mov word [lba_packet + LBAPkt_t.xfer_size], STAGE2_SECTOR_COUNT
    mov ax, [bp-2]
    shl eax, 16
    mov ax, [bp-4]
    mov dword [lba_packet + LBAPkt_t.lower_lba], eax
    mov ax, [bp-6]
    mov word [lba_packet + LBAPkt_t.offset], ax
    mov ax, [bp-8]
    mov word [lba_packet + LBAPkt_t.segment], ax
    mov si, lba_packet
    mov ah, 0x42
    mov dl, byte [boot_drive]
    int 0x13
    jnc read_disk_raw.endf
    mov al, 'B'
    jmp error
 .endf:
    pop si
    ret
 ; #############
 ;
 ; Locals
 ;
 ; #############
 boot_drive:
    db 0x00
 mbr_reserved1:
    db 0x00
 ; OFFSET from BEGINING of partition table, ie. DiskSig (-6 from PartEntry1)
 part_offset:
    dw 0x0000
 %assign bytes_remaining (440 - ($ - $$))
 %warning MBR has bytes_remaining bytes remaining for code (MAX: 440 bytes)
 times ((512 - 72) - ($ - $$)) nop     ; Fill the rest of sector with nop
 DiskSig:
    times 4 db 0x00
 Reserved1:
    db 0x00
 Reserved2:
    db 0x00
 PartEntry1:
    times 16 db 0x00
 PartEntry2:
    times 16 db 0x00
 PartEntry3:
    times 16 db 0x00
 PartEntry4:
    times 16 db 0x00
 BootSig:
    dw 0xAA55                    ; Add boot signature at the end of bootloader
--- a/src/miniboot32/BOOT_386.s
+++ b/src/miniboot32/BOOT_386.s
@@ -1,559 +0,0 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 32]
 [ORG 0x100000]
 [CPU KATMAI]
 jmp short start32
 nop
 ; Unless noted otherwise, functions will be the standard x86 cdecl used in GCC
 ; In cdecl, subroutine arguments are passed on the stack. 
 ; Integer values and memory addresses are returned in the EAX register,
 ; floating point values in the ST0 x87 register. 
 ; Registers EAX, ECX, and EDX are caller-saved, 
 ; and the rest are callee-saved. 
 ; The x87 floating point registers ST0 to ST7 must be empty (popped or freed) 
 ; when calling a new function, and ST1 to ST7 must be empty on exiting a function. 
 ; ST0 must also be empty when not used for returning a value. 
 ;
 ;   EXAMPLE: to call uint8_t* kmemset(uint8_t* dest, uint8_t val, uint8_t size);
 ;               => kmemset(*((char*) 0xb8000), 'F', (80*25))
 ;
 ;   push ebp                ; save old call frame pointer  
 ;   mov ebp, esp            ; new call frame pointer
 ;   push 0x000007D0         ; push args RTL, EBP - 4
 ;   push 'F'                ; *              EBP - 8
 ;   push 0x000b8000         ; *              EBP - 12
 ;   call kmemset            ; call function, this also places a return pointer on stack
 ;   add esp, 12             ; remove call arguments from stack frame
 ;   mov esp, ebp            ; restore stack frame pointer (callee saves EBP)
 ;   pop ebp                 ; restore call frame pointer
 ;
 ;
 ; 33 bytes BPB + 26 Byte EBPB
 struc BPBStruct
    .OemName        resb 8
    .BytesPerSect   resw 1
    .SecsPerClust   resb 1
    .ResSectors     resw 1
    .FATs           resb 1
    .RootDirEnts    resw 1
    .Sectors        resw 1
    .Media          resb 1
    .SectPerFAT     resw 1
    .SectPerTrack   resw 1
    .Heads          resw 1
    .Hidden         resd 1
    .SectorHuge     resd 1
    ; begin EBPB
    .DriveNumber    resb 1
    .NTReserved     resb 1
    .Signature      resb 1
    .VolumeID       resd 1
    .VolumeLabel    resb 11
    .SysIdent       resb 8
 endstruc
 ; 12 bytes
 struc FSInfoStruct
    .first_root_dir_sector resw 1
    .last_root_dir_sector  resw 1
    .root_dir_len          resw 1
    .first_data_sector     resw 1
    .active_cluster        resw 1
    .active_FAT_cluster    resw 1
 endstruc
 ; 20 bytes
 struc KInfoStruct
    .load_address          resd 1
    .file_len              resd 1
    .file_name             resb 8
    .file_ext              resb 3
    .reserved1             resb 1
 endstruc
 ; Address Range Descriptor Structure
 ;
 ; Offset in Bytes		Name		Description
 ;	0	    BaseAddrLow		u32 - Low 32 Bits of Base Address
 ;	4	    BaseAddrHigh	u32 - High 32 Bits of Base Address
 ;	8	    LengthLow		u32 - Low 32 Bits of Length in Bytes
 ;	12	    LengthHigh		u32 - High 32 Bits of Length in Bytes
 ;	16	    Type		    u32 - Address type of  this range.
 ;   20      ExtType         u32 -  ACPI 3.0 extended type
 struc AddressRangeDescStruct
    .BaseAddrLow    resd 1
    .BaseAddrHigh   resd 1
    .LengthLow      resd 1
    .LengthHigh     resd 1
    .Type           resd 1
    .ExtType        resd 1
 endstruc
 ; 20 bytes, passed to loaded kernel
 struc CBootInfoStruct
    .MemoryMapPtr      resd 1
    .MemoryMapEntries  resd 1
    .BPBDataPtr        resd 1
    .FSInfoPtr         resd 1
    .KInfoPtr          resd 1
 endstruc
 ;;;
 ; Errors
 ;   0 = unused
 ;   1 = No CPUID support on this platform (VM or some very old hardware?)
 ;   2 = magic signature not found at end of file
 ;   3 = Unexpected/unhandled artithmetic overflow/carry
 ;;;
 %define MAX_BYTES (1024 * 8)
 %define VGA_BUF 0xb8000
 ;black BG/Green FG
 %define TTY_COLOR 0x0200
 ;black BG/Red FG
 %define TTY_ERR_CLR 0x0400
 ;subtract 1 for max array values
 %define VGA_MAX_Y 25
 %define VGA_MAX_X 80
 ; VGA memory is row-major => offset = (row * MAX_Colums) + colum
 ; macro array is counted from 0,0 = 1,1 => 79,24 is the last usable space in a page
 %define VGA_OFFSET(x,y) (((y*VGA_MAX_X) + x)*2)
 start32:
    mov ax, 0x10
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax          ; load data registers with 2nd GDT selector
    mov esp, stack_top
    mov ebp, esp
 ; debugger hack because gdb doesn't like to switch register sizes
 ; issue a set $eax = 1 to continue
 %ifdef DEBUG_HACK
    mov eax, 0
 .gdb_hack:
    test eax, eax
    jz start32.gdb_hack
 %endif
    mov eax, dword [BOOT_SIG]
    cmp eax, 0xA0B0C0D0
    jz start32.signature_present
    mov al, "2"
    call error
 .signature_present:
    call check_cpuid
    push ebp
    mov ebp, esp
    lea eax, [welcome_cstr]
    push eax
    call vga_puts
    leave
    push ebp
    mov ebp, esp
    lea eax, [version_cstr]
    push eax
    call vga_puts
    leave
    push ebp
    mov ebp, esp
    lea eax, [datetime_cstr]
    push eax
    call vga_puts
    leave
    mov eax, VGA_BUF
    add eax, VGA_OFFSET(78, 24)
    mov dword [eax], 0x2f4b2f4f
    hlt
 ; Early error printer. Prints 'ERR: X' where X is an error code in al
 error:
    mov eax, VGA_BUF
    add eax, VGA_OFFSET(73, 24)
    mov dword [eax], 0x4f524f45
    add eax, 0x2
    mov dword [eax], 0x4f3a4f52
    add eax, 0x2
    mov dword [eax], 0x4f204f20
    add eax, 0x2
    mov byte  [eax], al
    hlt
 check_cpuid:
    ; flip cpuid id bit (bit 21) to check for cpuid support
    ; copy flags to eax via stack
    pushfd
    pop eax
    mov ecx, eax        ; copy to ecx for compare
    xor eax, 1 << 21    ; xor eax with the 21st bit set
    push eax            ; push new flags and pop to flags register
    popfd
    pushfd
    pop eax
    cmp eax, ecx        ; can we change the bit?
    je .no_cpuid
    ret
 .no_cpuid:
    mov al, "1"
    call error
 ; int vga_puts(char* str)
 ;
 ; INPUT: 
 ;   str: C-Sytle string
 ;
 ; OUTPUT:
 ;   EAX = characters printed
 ;
 vga_puts:
    ; prolog, EBP = SFP (Stack frame pointer), [EBP-4] = char* str
    push edi
    push esi
    push ebx
 .get_str_len:
    mov edi, [ebp - 4]
    xor ecx, ecx        ; ECX = 0
    not ecx             ; ECX = -1 == 0xFFFFFFFF
    xor eax, eax        ; search for al = 0x0
    cld
    repne scasb         ; deincrement ecx while searching for al
    not ecx             ; the inverse of a neg number = abs(x) - 1
    dec ecx             ; ECX contains the length of the string - nul byte at end
    mov edi, VGA_BUF    ; load dest index with VGA buffer + calculated offset
    mov esi, [ebp -4]   ; load source index with src string
    ; ECX = string length
    ; ESI = source string to print
    ; EDI = destination in the VGA buffer
 .print_char:
    cmp ecx, 0x0
    jle vga_puts.endf
    cmp byte [vga_buf_pos_x], 80
    je vga_puts.end_of_line
    cmp byte [vga_buf_pos_y], 25
    je vga_puts.scroll_up
    cmp byte [esi], 0x20
    jl vga_puts.special_character_switch
    push ebp
    mov ebp, esp
    xor eax, eax
    mov al, [vga_buf_pos_y]
    push eax                ; vga_pos_y
    xor eax, eax
    mov al, [vga_buf_pos_x]
    push eax                ; vga_pos_x
    ; uint16_t vga_calc_offset(uint8_t vga_pos_x, uint8_t vga_pos_y)
    call vga_calc_offset
    leave
    xor bx, bx
    mov bl, byte [esi]
    or bx, TTY_COLOR            ; create VGA character
    mov [edi+eax], bx
    inc esi
    inc byte [vga_buf_pos_x]
    dec ecx
    jmp vga_puts.print_char    ; loop until ECX == 0
 .end_of_line:
    ; advance to next row
    inc byte [vga_buf_pos_y]
    mov byte [vga_buf_pos_x], 0
    jmp vga_puts.print_char
 .scroll_up:
    ; after 25 rows, move to next page (either swap pages [memcpy] or erase page 0)
    mov byte [vga_buf_pos_x], 0
    mov byte [vga_buf_pos_y], 0
    push ebp
    mov ebp, esp
    mov eax, 0x7D0
    push eax        ; 1 VGA page = 0x7D0 elements
    xor eax, eax
    push eax        ; we want to blank the page with 0x0000
    mov eax, VGA_BUF
    push eax        ; load vga buffer base (0xb8000)
    ; uint16_t* kmemset_word(void* dest, uint16_t val, size_t len);
    call kmemset_byte
    leave
    jmp vga_puts.print_char
 .special_character_switch:
    cmp byte[esi], 0xA
    je vga_puts.handle_LF
    cmp byte[esi], 0xD
    je vga_puts.handle_CR
 ; Default case
 .special_character_endp:
    dec ecx
    inc esi
    jmp vga_puts.print_char
 .handle_LF:
    ; advance to next row
    inc byte [vga_buf_pos_y]
    jmp vga_puts.special_character_endp
 .handle_CR:
    mov byte [vga_buf_pos_x], 0
    jmp vga_puts.special_character_endp
 .endf:
    pop ebx
    pop esi
    pop edi
    ret
 ; short vga_get_xy(void)
 ;
 ; INPUT: 
 ;
 ; OUTPUT:
 ;   EAX = xy_pos
 ;      > x = xy_pos && 0xFF00
 ;        y = xy_pos && 0x00FF
 ;   2 MSB of EAX are 0.
 ;
 vga_get_xy:
 .endf:
    ret
 ; void vga_set_xy(short xy_pos)
 ;   xy_pos is a byte packed word (16bit value), MSB is x, LSB is y
 ;       => x = xy_pos && 0xFF00
 ;          y = xy_pos && 0x00FF
 ;
 ; INPUT: 
 ;   xy_pos
 ;
 ; OUTPUT:
 ;   NONE
 ;
 vga_set_xy:
 .endf:
    ret
 ; uint16_t vga_calc_offset(uint8_t vga_pos_x, uint8_t vga_pos_y)
 ; VGA_OFFSET(x,y) == (((y*VGA_MAX_X) + x)*2)
 vga_calc_offset:
    xor eax, eax
    xor edx, edx
    mov edx, [ebp-4]
    mov ax, VGA_MAX_X
    mul dx              ; DX:AX contains (y*VGA_MAX_X)
    jc vga_calc_offset.artithmetic_error
    mov edx, [ebp-8]
    add ax, dx
    jc vga_calc_offset.artithmetic_error
    mov dx, 0x02
    mul dx              ; DX:AX contains (y*VGA_MAX_X) + x) * 2
    jnc vga_calc_offset.endf
 .artithmetic_error:
    mov al, '3'
    call error
 .endf:
    ; (e)AX contains the offset
    ret
 ; uint32_t* kmemset(void* dest, uint32_t val, size_t len);
 kmemset_dword:
    push    edi             ; function uses edi, so save it.
                            ; [ebp] = previous call frame
    mov     ecx, [ebp - 4]  ; size_t len
    mov     eax, [ebp - 8]  ; uint32_t val
    mov     edi, [ebp - 12] ; void * ptr
                            ; [ebp - 16] = return adress
                            ; [ebp - 20] = saved EDI
    rep     stosd 
 .endf:
    mov     eax, [ebp - 12] ; return pointer to dest
    pop     edi             ; restore edi
    ret
 ; uint16_t* kmemset(void* dest, uint16_t val, size_t len);
 kmemset_word:
    push    edi             ; function uses edi, so save it.
                            ; [ebp] = previous call frame
    mov     ecx, [ebp - 4]  ; size_t len
    mov     ax, [ebp - 8]   ; uint16_t val
    mov     edi, [ebp - 12] ; void * ptr
                            ; [ebp - 16] = return adress
                            ; [ebp - 20] = saved EDI
    rep     stosw 
 .endf:
    mov     eax, [ebp - 12] ; return pointer to dest
    pop     edi             ; restore edi
    ret
 ; uint8_t* kmemset(void* dest, uint8_t val, size_t len);
 kmemset_byte:
    push    edi             ; function uses edi, so save it.
                            ; [ebp] = previous call frame
    mov     ecx, [ebp - 4]  ; size_t len
    mov     al, [ebp - 8]   ; uint8_t val
    mov     edi, [ebp - 12] ; void * ptr
                            ; [ebp - 16] = return adress
                            ; [ebp - 20] = saved EDI
    rep     stosb 
 .endf:
    mov     eax, [ebp - 12] ; return pointer to dest
    pop     edi             ; restore edi
    ret
 ; uint32_t* kmemset(uint32_t* dest, uint32_t* src, size_t len);
 kmemcpy_dword:
    push edi
    push esi                ; edi, esi are callee save
    mov edi, [ebp-12]       ; dest
    mov esi, [ebp-8]        ; source
    mov ecx, [ebp-4]        ; length
    cld                     ; ensure we are incrementing
    rep movsd
 .endf:
    mov eax, [ebp-12]       ; return pointer to dest
    pop esi
    pop edi
    ret
 ; uint16_t* kmemset(uint16_t* dest, uint16_t* src, size_t len);
 kmemcpy_word:
    push edi
    push esi                ; edi, esi are callee save
    mov edi, [ebp-12]       ; dest
    mov esi, [ebp-8]        ; source
    mov ecx, [ebp-4]        ; length
    cld                     ; ensure we are incrementing
    rep movsw
 .endf:
    mov eax, [ebp-12]       ; return pointer to dest
    pop esi
    pop edi
    ret
 ; uint8_t* kmemset(uint8_t* dest, uint8_t* src, size_t len);
 ; not overlap safe
 kmemcpy_byte:
    push edi
    push esi                ; edi, esi are callee save
    mov edi, [ebp-12]       ; dest
    mov esi, [ebp-8]        ; source
    mov ecx, [ebp-4]        ; length
    cld                     ; ensure we are incrementing
    rep movsb
 .endf:
    mov eax, [ebp-12]       ; return pointer to dest
    pop esi
    pop edi
    ret
 ; Static Values
 vga_buf_pos_x:
    db 0x00
 vga_buf_pos_y:
    db 0x00
 ; Strings
 %define StrCRLF_NUL 0Dh, 0Ah, 00h
 welcome_cstr:
    db 'CBoot Stage3', StrCRLF_NUL
 version_cstr:
    db 'CBoot v0.0.3 ', 'NASM - ', __NASM_VER__, StrCRLF_NUL
 datetime_cstr:
    db 'Assembled - ', __DATE__, ' ', __TIME__, StrCRLF_NUL
 ALIGN 16, db 0
 stack_bottom:
    times (512 * 8) db 0x00       ; 4KiB stack
 stack_top:
 %assign bytes_remaining ((MAX_BYTES - 4) - ($ - $$))
 %warning boot32 has bytes_remaining bytes remaining for code (MAX: MMAX_BYTES)
 times ((MAX_BYTES - 4) - ($ - $$)) db 0xFE
 BOOT_SIG: dd 0xA0B0C0D0
--- a/src/miniboot32/BOOTi686.nasm
+++ b/src/miniboot32/BOOTi686.nasm
@@ -0,0 +1,99 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 32]
 [ORG 0x100000]
 [CPU KATMAI]
 jmp short (init32 - $$)         ; PI jump
 nop
 ;;;
 ; Errors
 ;   0 = unused
 ;   E = General Error
 ;   S = magic signature not found at end of file
 ;   O = OK
 ;;;
 %define MAX_BYTES (1024 * 8)
 %define VGA_BUF 0xb8000
 ; VGA memory is row-major => offset = (row * MAX_Colums) + colum
 ; macro array is counted from 0,0 = 1,1 => 79,24 is the last usable space in a page
 %define VGA_OFFSET(x,y) (((y*VGA_MAX_X) + x)*2)
 ;subtract 1 for max array values
 %define VGA_MAX_Y 25
 %define VGA_MAX_X 80
 ALIGN 16, db 0
 init32:
    mov ax, 0x10        ; 0x10 selector segment
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax          ; load data registers with 2nd GDT selector
    mov esp, stack_top
    mov ebp, esp
    mov eax, dword [BOOT_SIG]
    cmp eax, 0xA0B0C0D0
    jz .signature_present
    mov dl, "S"
    jmp .result
 .signature_present:
    mov dl, "O"
 .result:
    mov eax, VGA_BUF
    add eax, VGA_OFFSET(73, 24)
    mov dword [eax], 0x1f451f52
    add eax, 0x4
    mov dword [eax], 0x1f3e1f53
    add eax, 0x4
    ; RES> in white-on-blue
    mov ecx, 0x1f201f20
    and cl, dl                          ; 0x1f201f(dl)
    ror ecx, 16                         ; 0x1f(dl)1f20 = ' (dl)'
    mov dword [eax], ecx                ; should be a space and contents of dl
 .endp:
    hlt
    jmp .endp - $$
 ; Strings
 ALIGN 16, db 0
 %define StrCRLF_NUL 0Dh, 0Ah, 00h
 version_cstr:
    db 'CBoot v0.0.3 ', 'NASM - ', __NASM_VER__, StrCRLF_NUL
 datetime_cstr:
    db 'Assembled - ', __DATE__, ' ', __TIME__, StrCRLF_NUL
 ALIGN 16, db 0
 stack_bottom:
    times (512 * 8) db 0x00       ; 4KiB stack
 stack_top:
 %assign bytes_remaining ((MAX_BYTES - 4) - ($ - $$))
 %warning boot32 has bytes_remaining bytes remaining for code (MAX: MMAX_BYTES)
 times ((MAX_BYTES - 4) - ($ - $$)) db 0xFE
 BOOT_SIG: dd 0xA0B0C0D0
--- a/src/stage2/stage2.nasm
+++ b/src/stage2/stage2.nasm
@@ -0,0 +1,564 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 16]
 [ORG 0x0500]                            ; IF YOU CHANGE ORG CHANGE THE SIGN OFFSET AT THE END
 [CPU KATMAI]
 [map all stage2.map]
 [WARNING -reloc-abs-byte]
 [WARNING -reloc-abs-word]
 [WARNING -reloc-abs-dword]              ; Yes, we use absolute addresses. surpress these warnings.
 %define __STEVIA_STAGE2
 %define __STAGE2_SEGMENT 0x0000
 ; ###############
 ; Headers/Includes/Definitions
 ; ###############
 %include "util/bochs_magic.inc"
 %include "cdecl16.inc"
 %include "entry.inc"
 %include "config.inc"
 %include "early_mem.inc"
 %include "error_codes.inc"
 %macro print_string 1
    mov ax, %1
    push ax
    call PrintString
    add sp, 0x2
 %endmacro
 section .text
 begin_text:
 ; dl = byte boot_drive
 ; ax = word part_offset (active partition offset)
 ; si = ptr PartTable_t partition_table
 ; di = ptr FAT32_bpb_t fat32_bpb
 ALIGN 4, db 0x90
 init:
    cli                               ; We do not want to be interrupted
    ; these 4 are stored in the .data section and are effectivly const types
    mov [vbr_part_table_ptr], si             ; pointer to partition_table
    mov [vbr_fat32_bpb_ptr], di              ; pointer to fat32_bpb
    mov [boot_drive], dl                     ; copy boot_drive to globals
    mov [partition_offset], ax               ; copy partition_offset to globals
    mov ax, __STAGE2_SEGMENT          ; set all our segments to the configured segment, except es
    mov ds, ax                        ; *
    mov fs, ax                        ; *
    mov gs, ax                        ; *
    mov ss, ax
    ; Zero BSS section
    mov cx, (end_bss - begin_bss)     ; count = bss length
    mov ax, begin_bss
    shr ax, 4
    mov es, ax                        ; es = begining of bss section, remember to restore ES later
    xor ax, ax                        ; val = 0
    mov di, ax                        ; dst = 0 (start of segment)
    cld
    rep stosb 
    mov ax, __STAGE2_SEGMENT
    mov es, ax  
    ; done zeroing bss section
    mov sp, stack_top
    mov bp, sp
    sub sp, 0x10
    push bp                           ; setup a somewhat normal stack frame, minus a ret ptr
    sti
    jmp word __STAGE2_SEGMENT:main
 ; ###############
 ; Functions
 ; ###############
 %include "util/kmem_func.nasm"
 %include "util/kmemcpy5_func.nasm"
 %include "util/kmemset4_func.nasm"
 %include "util/error_func.nasm"
 ; ###############
 ; FAT32 Driver
 ; ###############
 %include 'fat32/FAT32_SYS.inc'
 ; ###############
 ; BIOS functions
 ; ###############
 %include 'BIOS/BIOS_SYS.inc'
 ; structures
 struc SteviaInfoStruct_t
    .MemoryMapPtr      resd 1
    .MemoryMapEntries  resd 1
 endstruc
 struc EarlyBootStruct_t
    .partition_table resb PartTable_t_size
    .fat32_bpb       resb FAT32_bpb_t_size
    .fat32_ebpb      resb FAT32_ebpb_t_size
 endstruc
 ALIGN 4, db 0x90
 main:
    __BOCHS_MAGIC_DEBUG
 .check_sig:
    mov eax, dword [STAGE2_SIG]
    cmp eax, 0xDEADBEEF
    je main.stage2_main
    ERROR STAGE2_SIGNATURE_MISSING
 .stage2_main:
    mov ax, PartTable_t_size
    push ax                                                 ; len = PartTable_t_size
    mov ax, word [vbr_part_table_ptr]                       ; src = ptr to vbr partition_table
    push ax
    mov ax, partition_table                                 ; dst
    push ax
    call kmemcpy                                            ; copy partition table data to .data section in stage2
    add sp, 0x6
    mov ax, (FAT32_bpb_t_size + FAT32_ebpb_t_size)          ; len
    push ax
    mov ax, word [vbr_fat32_bpb_ptr]                        ; src            
    push ax
    mov ax, fat32_bpb                                       ; dst
    push ax
    call kmemcpy                                            ; copy bpb & ebpb to memory
    add sp, 0x6
    call SetTextMode
    call disable_cursor
    print_string HelloPrompt_cstr
    ; enable A20 gate
    call EnableA20
    print_string A20_Enabled_OK_cstr
    ; get system memory map
    call GetMemoryMap
    print_string MemoryMap_OK_cstr
    ; enter unreal mode
    call EnterUnrealMode
    print_string UnrealMode_OK_cstr
    ; FAT Driver setup
    call InitFATDriver
    print_string InitFATSYS_OK_cstr
    ;
    ; Find first cluster of bootable file
    call SearchFATDIR
    push dword eax      ; save first cluster of bootable file
    print_string FileFound_OK_cstr
    pop dword eax
    push dword eax      ; print Cluster of boot file
    call PrintDWORD     ; void PrintDWORD(uint32_t dword)
    print_string NewLine_cstr
    ; TODO: using first cluster information, start loading the kernel to memory
    ; TODO: going to need an elf parser,  some unreal mode file buffer functions to move the data
 hcf:
    ERROR STEVIA_DEBUG_OK
 ; ##############################
 ;
 ; SYSTEM CONFIGURATION FUNCTIONS
 ;
 ; ##############################
 ; Prints a C-Style string (null terminated) using BIOS vga teletype call
 ; void PrintString(char* buf)
 ALIGN 4, db 0x90
 PrintString:
    __CDECL16_ENTRY
    mov di, [bp + 4]    ; first arg is char* 
 .str_len:
    xor cx, cx         ; ECX = 0
    not cx             ; ECX = -1 == 0xFFFF
    xor ax, ax         ; search for al = 0x0
    cld
    repne scasb        ; deincrement cx while searching for al
    not cx             ; the inverse of a neg number = abs(x) - 1
    dec cx             ; CX contains the length of the string - nul byte at end
 .print:
    mov si, [bp + 4]            ; source string
 .print_L0:
    movzx ax, byte [si]
    push ax
    call PrintCharacter
    add sp, 0x2
    inc si
    dec cx
    jcxz PrintString.endp
    jmp PrintString.print_L0    ; Fetch next character from string
 .endp:
    __CDECL16_EXIT
    ret                         ; Return from procedure
 ; Prints a single character
 ; void PrintCharacter(char c);
 ALIGN 4, db 0x90
 PrintCharacter:
    __CDECL16_ENTRY
 .func:
    mov ax, [bp + 4] ; c
    mov dx, 0x00ff
    and ax, dx
    mov ah, 0x0E                ; INT 0x10, AH=0x0E call
    mov bx, 0x0007              ; BH = page no. BL =Text attribute 0x07 is lightgrey font on black background
    int 0x10                    ; call video interrupt
 .endp:
    __CDECL16_EXIT
    ret
 ; TODO: fix the prolog, epilog and stack usage to confirm with cdecl16
 ; prints the hex representation of of val
 ; void PrintDWORD(uint32_t val);
 ALIGN 4, db 0x90
 PrintDWORD:
    __CDECL16_ENTRY
 .func: 
    lea si, [IntToHex_table]
    mov ebx, 16     ; base-16
    mov eax, dword [bp + 4]     ;val
    xor edx, edx
    xor cx, cx
 .next_digit:
    div ebx            ; dividend in edx:eax -> quotient in eax, remainder in edx
    push dx            ; save remainder
    inc cx
    xor dx, dx
    test eax, eax
    jnz PrintDWORD.next_digit
 .zero_pad:
    cmp cx, 0x0008
    je PrintDWORD.print_stack
    xor ax, ax
    push ax
    inc cx
    jmp PrintDWORD.zero_pad
 .print_stack:
    pop bx
    dec cx
    push cx
    movzx ax, byte [bx+si+0]    ; bx = index into Hex lookup table
    push ax
    call PrintCharacter
    add sp, 0x2
    pop cx
    jcxz PrintDWORD.endp
    jmp PrintDWORD.print_stack
 .endp:
    __CDECL16_EXIT
    ret
 ; ##############################
 ;
 ; SYSTEM CONFIGURATION FUNCTIONS
 ;
 ; ##############################
 ALIGN 4, db 0x90
 EnterUnrealMode:
    __CDECL16_ENTRY
 .func:
    cli                         ; no interrupts
    push ds                     ; save real mode data/stack selectors
    push es
    push fs
    push gs
    push ss
    push cs                               ; save real mode code selector
    xor ax, ax                            ;
    pop ax                                ; save cs to ax to setup far jump
    mov word [__UNREAL_SEGMENT], ax    
    lgdt [((__STAGE2_SEGMENT << 4) + unreal_gdt_info)]                 ; load unreal gdt
    mov eax, cr0                          
    or al,1                               ; set pmode bit
    mov cr0, eax                          ; switch to pmode
    jmp short $+2
    ;jmp far 0x0008:EnterUnrealMode.load_cs
    db 0xEA                               ; jmp far imm16:imm16
    dw EnterUnrealMode.load_cs            ; error_far_ptr
    dw 0x0008                             ; error_far_seg
 .load_cs:
    mov bx, 0x10                          ; select descriptor 2
    mov ds, bx                            ; 10h = 0001_0000b
    mov ss, bx
    mov es, bx
    mov fs, bx
    mov gs, bx                            ; other data/stack to index 2 (off 0x10)
    and al,0xFE                           ; toggle bit 1 of cr0
    mov cr0, eax                          ; back to realmode
    jmp short $+2
    ;jmp far 0x0008:EnterUnrealMode.unload_cs
    db 0xEA                               ; jmp far imm16:imm16
    dw EnterUnrealMode.unload_cs          ; error_far_ptr
 __UNREAL_SEGMENT:
    dw 0x0000                             ; error_far_seg
 EnterUnrealMode.unload_cs:
    pop ss
    pop gs
    pop fs
    pop es
    pop ds                                ; get back old segments
    sti
 .endp:
    __CDECL16_EXIT
    ret
 end_text:
 section .data follows=.text
 align 512
 begin_data:
 ; #############
 ;
 ; Strings
 ;
 ; #############
 %macro define_str 2
    ALIGN 16
    %1_str:
        db %2
    %define str_len %strlen(%2)       ; string
    %1_str_len:
        dd str_len
 %endmacro
 ; TODO: technically this is a cstr but it splices a return and newline on the end
 ; TODO: this probably should be seperated out and the printing functionality should
 ; TODO: place that newline and return
 %macro define_cstr 2
 %define CRLF_NUL 0Dh, 0Ah, 00h
    ALIGN 16
    %1_cstr:
        db %2, CRLF_NUL
 %endmacro
 define_cstr HelloPrompt, "Hello from Stevia Stage2!"
 define_cstr A20_Enabled_OK, "A20 Enabled OK"
 define_cstr MemoryMap_OK, "Memory map OK"
 define_cstr UnrealMode_OK, "Unreal mode OK"
 define_cstr FileFound_OK, "Found SFN entry for bootable binary, first cluster -> "
 define_cstr InitFATSYS_OK, "FAT32 Driver Init..."
 define_cstr SearchFATDIR_INFO, "Searching FAT DIR for bootable file..."
 define_cstr NextFATCluster_INFO, "Attempting to find next FAT cluster..."
 define_cstr ReadFATCluster_INFO, "Attempting to load next FAT"
 define_cstr MaybeFound_Boot_INFO, "Maybe found a file...checking..."
 define_cstr NewLine, ""
 define_str BootTarget, "BOOT    BIN"
 ;
 ; pre-bss init globals (generally const...but there are exceptions)
 ;
 align 8, db 0x00
 boot_drive:
    db 0x00
 align 8, db 0x00
 partition_offset:
    dw 0x0000
 align 8, db 0x00
 vbr_fat32_bpb_ptr:
    dw 0x0000
 align 8, db 0x00
 vbr_part_table_ptr:
    dw 0x0000
 ALIGN 16
 IntToHex_table:
    db '0123456789ABCDEF'
 ; see docs/gdt.txt for a quick refresher on GDT 
 ALIGN 16, db 0
 unreal_gdt_info:
    unreal_gdt_size: dw (unreal_gdt_end - unreal_gdt_start) - 1
    unreal_gdt_ptr:  dd ((__STAGE2_SEGMENT << 4) + unreal_gdt_start)
 unreal_gdt_start:
    ; entry 0 (null descriptor)
    dq 0                    ; first entry is null
    ; entry 1 (16bit code 64KiB limit)
    dd 0x0000FFFF        ; Base Address(15:0) 31:16, Segment Limit(15:0) 15:0
    db 0x00              ; Base Address 23:16
    db 1001_1010b        ; Access Byte: Present, ring0, S = 1, executable (1), non-conforming, readable, Accessed
    db 0000_0000b        ; Flags: GR = 4KiB, attr = <DB/L/Avl>, Granularity = 4KiB & 16:19 of limit
    db 0x00              ; Base Address 31:24
    ; entry 2 (16bit data segment with 4 GiB flat mapping)
    dd 0x0000FFFF        ; Base Address(15:0) 31:16, Segment Limit(15:0) 15:0
    db 0x00              ; Base Address(23:16)
    db 1001_0010b        ; Access Byte: Present, ring0, S = 1, data (0), non-confirming, writable, present
    db 1000_1111b        ; Flags: GR = 4KiB, attr = <16-bit/?/?>, Granularity = 4KiB & 16:19 of limit
    db 0x00              ; Base Address(31:24)
 unreal_gdt_end:
 ALIGN 16, db 0
 gdt32_info:
    gdt32_size: dw (gdt32_end - gdt32_start) - 1
    gdt32_ptr:  dd ((__STAGE2_SEGMENT << 4) + gdt32_start)
 gdt32_start:
    dq 0
    .gdt32_code:
        dw 0xFFFF       ; code segment (RX)
        dw 0x0000
        db 0x00
        db 1001_1000b   ; Access: readable, executable
        db 1100_1111b   ; 4KB granularity, 32-bit
        db 0x00
    .gdt32_data:        ; data segment (RW)
        dw 0xFFFF
        dw 0x0000
        db 0x00
        db 1001_0010b    ; Access: readable, writable
        db 1100_1111b    ; 4KB granularity, 32-bit
        db 0x00
    .gdt32_stack:        ; Stack segment (RW)
        dw 0xFFFF
        dw 0x0000
        db 0x00
        db 1001_0010b    ; Access: readable, writable
        db 1100_1111b    ; 4KB granularity, 32-bit
        db 0x00
    .gdt32_ro_data:      ; Read-only data segment (RO)
        dw 0xFFFF
        dw 0x0000
        db 0x00
        db 1001_0000b    ; Access: readable, not writable
        db 1100_1111b    ; 4KB granularity, 32-bit
        db 0x00
 gdt32_end:
 ALIGN 8,db 0x00
 BUILD_NASM_VER:
    db "Stevia Stage2 built with NASM - ", __NASM_VER__, 00h
 ALIGN 8,db 0x00
 BUILD_DATETIME:
    db 'Assembled - ', __DATE__, ' ', __TIME__, 00h
 ALIGN 8,db 0x00
 BUILD_GIT_VER:
    db __GIT_VER__, 00h
 ALIGN 8,db 0x00
 BUILD_GIT_HASH:
    db __GIT_HASH__, 00h
 end_data:
 %assign bytes_remaining ((MAX_STAGE2_BYTES - 4) - (($ - $$) + (end_text - begin_text)))
 %warning STAGE2 has bytes_remaining bytes remaining for code/data (MAX: MAX_STAGE2_BYTES)
 ; section start location needs to be a 'critical expression'
 ; i.e resolvable at build time, we are setting 0x7E00 as the offset since
 section .sign start=((MAX_STAGE2_BYTES - 512) + 0x0500)
 times ((512 - 4) - ($ -$$) ) db 0x90     ; nop
 STAGE2_SIG: dd 0xDEADBEEF                ; Signature to mark the end of the stage2
 section .bss follows=.sign
 begin_bss:
 ; structures
 align 8, resb 1
 partition_table resb PartTable_t_size
 align 8, resb 1
 fat32_bpb resb FAT32_bpb_t_size
 fat32_ebpb resb FAT32_ebpb_t_size
 align 8, resb 1
 fat32_nc_data resb 16
 align 8, resb 1
 lba_packet resb LBAPkt_t_size
 align 8, resb 1
 fat32_state:
    resb FAT32_State_t_size
 align 8, resb 1
 SteviaInfo:
    resd 4
 ;
 ; post-bss init globals
 ;
 ;
 ; large continuous allocations
 ;
 align 16, resb 1
 disk_buffer:
    resb 512
 fat_buffer:
    resb 512
 dir_buffer:
    resb 512
 fat_fsinfo:
    resb 512
 align 16, resb 1
 %define BIOSMemoryMap_SIZE 2048
 BIOSMemoryMap:
    resb 2048
 align 512, resb 1
 stack_bottom:
    resb 1024
 stack_top:
 end_bss:
--- a/src/stage2/stage2.s
+++ b/src/stage2/stage2.s
--- a/src/vbr/vbr.nasm
+++ b/src/vbr/vbr.nasm
@@ -0,0 +1,195 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 16]
 [ORG 0x7C00]
 [CPU KATMAI]
 [WARNING -reloc-abs-byte]
 [WARNING -reloc-abs-word]
 [map all vbr.map]                   ; Yes, we use absolute addresses. surpress these warnings.
 %define __STEVIA_VBR
 section .text
 __ENTRY:
    jmp short (init - $$)
    nop
 ; fill BPB area with 0x00 since we skip writing this part to disk
 ; but we need it for the 'jmp short entry; nop' above
 times 33 db 0x00
 phy_ebpb_start:
 ; fill eBPB area with 0x00 since we skip writing this part to disk
 times 54 db 0x00
 ; ###############
 ;
 ; Headers/Includes/Definitions
 ;
 ; ###############
 %include "util/bochs_magic.inc"
 %include "cdecl16.inc"
 %include "entry.inc"
 %include "config.inc"
 %include "early_mem.inc"
 %include "error_codes.inc"
 %include "partition_table.inc"
 %include "fat32/fat32_structures.inc"
 %undef __STEVIA_DEV_DEBUG
 ; dl = boot_drive
 ; si = part_offset
 ; bx = partition_table location from mbr
 ALIGN 4
 init:
    cli                             ; We do not want to be interrupted
    xor ax, ax                      
    mov ds, ax                      ; Set segment registers to 0x0000
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax                      ; Set Stack Segment to 0
    mov sp, end_bss                 ; Setup stack
    mov bp, sp                      ; base ptr = stack ptr
    ; zero bss section
    mov cx, (end_bss - begin_bss)     ; count = bss length                    
    mov ax, begin_bss
    mov di, ax                        ; es:di is dest
    xor ax, ax
    cld
    rep stosb                          
    sub sp, 0x20                    ; local varible space
    push bp
    sti                             ; all done with inital setup and relocation, reenable interupts
    jmp 0:main                      ; fix up cs:ip just in case and jump to relocated code
 ; ###############
 ; Extra/Shared Functions
 ; ###############
 %include "util/kmem_func.nasm"
 %include "util/error_func.nasm"
 ; ###############
 ; End Section
 ; ###############
 ;
 ; byte boot_drive @ bp - 2
 ; word part_offset @ bp - 4
 ; ptr partition_table
 ALIGN 4, db 0x90
 main:
    mov byte [bp - 2], dl                 ; boot_drive
    mov word [bp - 4], si                 ; part_offset
    mov word [bp - 6], bx                 ; partition_table
 .load_fs_data:
    mov ax, PartTable_t_size                           ; count=
    push ax                                             
    mov ax, [bp - 6]                                   ; src= ptr partition_table
    push ax
    mov ax, partition_table                            ; dst=      
    push ax
    call kmemcpy                                       ; copy partition table data
    add sp, 0x6
    mov ax, (FAT32_bpb_t_size + FAT32_ebpb_t_size)     ; size in byte, should be 90 bytes
    push ax
    mov ax, __ENTRY                                    
    push ax
    mov ax, fat32_bpb                                  ; 
    push ax
    call kmemcpy                                       ; copy bpb & ebpb to memory
    add sp, 0x6
 .check_FAT_size:                     ; we only support a very specific setup of FAT32
    mov bx, fat32_bpb
    cmp dword [bx + FAT32_bpb_t.sector_count_32], 0      ; SectorsHuge will not be set if FAT12/16
    ja main.load_stage2
    ERROR VBR_ERROR_WRONG_FAT_SIZE
 .load_stage2:
    ; read sectors 1-(MAX_STAGE2_BYTES / 512) to stage2 entry point
    movzx ax, byte [bp - 2]
    push ax                                            ; drive_num
    mov ax, STAGE2_SECTOR_COUNT
    push ax                                            ; count
    mov dword eax, 0x1
    push dword eax                                     ; lba
    mov ax, STAGE2_ENTRY
    push ax                                            ; offset
    xor ax, ax
    push ax                                            ; segment = 0
    ; uint8_t read_stage2_raw(uint16_t buf_segment, uint16_t buf_offset, 
    ;                         uint32_t lba,
    ;                         uint16_t count, uint16_t drive_num)
    call read_disk_raw
    add sp, 0xC
 .enter_stage2:
    mov dl, byte [bp - 2]               ; byte boot_drive
    mov ax, word [bp - 4]               ; word part_offset
    mov si, partition_table             ; ptr partition_table
    mov di, fat32_bpb                   ; ptr fat32_bpb
    jmp word 0x0000:STAGE2_ENTRY
 ; ###############
 ; Required BIOS function(s)
 ; ###############
 %include 'BIOS/func/ext_read.nasm'
 %assign bytes_remaining (420 - ($ - $$))
 %warning VBR has bytes_remaining bytes remaining for code (MAX: 420 bytes)
 times (510 - ($ - $$)) nop     ; Fill the rest of sector with nop
 BootSig:
    dw 0xAA55                    ; Add boot signature at the end of bootloader
 section .bss follows=.text
 begin_bss:
 align 16, resb 1
 partition_table resb PartTable_t_size
 align 16, resb 1
 fat32_bpb resb FAT32_bpb_t_size
 fat32_ebpb resb FAT32_ebpb_t_size
 align 16, resb 1
 fat32_nc_data resb 16
 align 16, resb 1
 lba_packet resb LBAPkt_t_size
 align 512, resb 1
 stack_bottom resb 512                  ; 512b stack early on
 stack_top:
 vbr_redzone resb 32
 end_bss:
--- a/src/vbr/vbr.s
+++ b/src/vbr/vbr.s
@@ -1,225 +0,0 @@
 ; Copyright (c) 2023 Elaina Claus
 ;
 ; Permission is hereby granted, free of charge, to any person obtaining a copy
 ; of this software and associated documentation files (the "Software"), to deal
 ; in the Software without restriction, including without limitation the rights
 ; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 ; copies of the Software, and to permit persons to whom the Software is
 ; furnished to do so, subject to the following conditions:
 ;
 ; The above copyright notice and this permission notice shall be included in all
 ; copies or substantial portions of the Software.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 ; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 ; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 ; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 ; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 ; SOFTWARE.
 [BITS 16]
 [ORG 0x7C00]
 [CPU KATMAI]
 jmp short init
 nop
 bpb_start:
 ; fill BPB area with 0x00 since we skip writing this part to disk
 ; but we need it for the 'jmp short entry; nop' above
 times 33 db 0x00
 ebpb_start:
 ; fill BPB area with 0x00 since we skip writing this part to disk
 ; but we need it for the 'jmp short entry; nop' above
 times 54 db 0x00
 %include "entry.inc"
 init:
    cli                         ; We do not want to be interrupted
    xor ax, ax                  ; 0 AX
    mov ds, ax                  ; Set segment registers to 0
    mov es, ax                  ; *
    mov ss, ax                  ; Set Stack Segment to 0
    mov sp, STACK_START         ; Setup stack
    mov bp, sp                  ; base ptr = stack ptr
    mov bx, VBR_ENTRY           ; move BP to the new start of the initial boot sector
    jmp 0:main                  ; fix up cs:ip just in case and jump to relocated code
 %include "config.inc"
 %include "errors.inc"
 %include "memory.inc"
 %include "partition_table.inc"
 %include "fat32/bpb.inc"
 main:
    sti                         ; all done with inital setup and relocation, reenable interupts
    mov [bsDriveNumber], dl     ; BIOS passes drive number in DL
    mov [partition_offset], si  ; save passed partition entry offset
 .check_FAT_size:
    cmp dword [bsSectorHuge], 0      ; SectorsHuge will not be set if FAT12/16
    ja main.load_stage2
    ERROR VBR_ERROR_WRONG_FAT_SIZE
 ; read sectors 1-63 to stage2 entry point
 .load_stage2:
    push bp
    mov bp, sp
    ;uint8_t read_disk_raw(size_t count, uint16_t buf_segment, uint16_t buf_offset, 
    ;                      uint16_t lower_lower_lba, uint16_t upper_lower_lba)
    xor ax, ax
    push ax         ; upper_lower_lba = 0
    mov ax , 1
    push ax         ; lower_lower_lba = 1
    xor ax, ax
    push ax          ; offset = 0
    ; 07E0:0
    mov ax, STAGE2_ENTRY
    shr ax, 4
    push ax          ; segment = 7E0
    mov ax, STAGE2_SECTOR_COUNT
    push ax
    call read_disk_raw
    leave
 .check_sig:
    mov ax, 0x7E0
    mov fs, ax
    cmp dword [fs:0x7FFC], 0xDEADBEEF
    je main.sig_ok
    ERROR VBR_ERROR_NO_SIGNATURE          ; no signature present in stage2
 .sig_ok:
    push bp
    mov bp, sp
    mov ax, fat32_bpb_SIZE          ; size in byte
    push ax
    mov ax, bpb_start               ; start of bpb
    push ax
    mov ax, fat32_bpb               ; defined in memory.inc, destination
    push ax
    call kmemcpy                    ; copy bpb to memory
    leave
    push bp
    mov bp, sp
    mov ax, fat32_ebpb_SIZE          ; 72 bytes of data
    push ax
    mov ax, ebpb_start               ; start of ebpb
    push ax
    mov ax, fat32_ebpb               ; defined in memory.inc, destination
    push ax
    call kmemcpy                     ; copy ebpb to memory
    leave
    mov si, [partition_offset]
    mov dl, [bsDriveNumber]
    jmp 0:0x7E00
 stop:
    hlt
    jmp short stop
 ; Wrapper for AH=0x42 INT13h (Extended Read)
 ;
 ; BIOS call details
 ; AH = 42h
 ; DL = drive number
 ; DS:SI -> disk address packet
 ;
 ; Return:
 ; CF clear if successful
 ; AH = 00h
 ; CF set on error
 ; AH = error code
 ; disk address packet's block count field set to number of blocks
 ; successfully transferred
 ;
 ;
 ; uint8_t read_disk_raw(uint16_t buf_segment, uint16_t buf_offset, uint16_t lower_lower_lba, uint16_t upper_lower_lba)
 ; bp-0 = call frame
 ; bp-2 = upper_lower_lba
 ; bp-4 = lower_lower_lba
 ; bp-6 = offset
 ; bp-8 = segment
 ; bp-10 = count
 ; bp-12 = ret ptr
 read_disk_raw:
    push si
    ; uint8_t* kmemset(void* dest, uint8_t val, size_t len);
    push bp
    mov bp, sp
    mov ax, 0x10
    push ax             ; len = 16 bytes
    xor ax, ax
    push ax             ; val = 0
    mov ax, lba_packet
    push ax             ; dest = lba_packet address
    call kmemset
    leave
    mov byte [lba_packet + LBAPkt_t.size], 0x10
    mov word [lba_packet + LBAPkt_t.xfer_size], STAGE2_SECTOR_COUNT
    mov ax, [bp-2]
    shl eax, 16
    mov ax, [bp-4]
    mov dword [lba_packet + LBAPkt_t.lower_lba], eax
    mov ax, [bp-6]
    mov word [lba_packet + LBAPkt_t.offset], ax
    mov ax, [bp-8]
    mov word [lba_packet + LBAPkt_t.segment], ax
    mov si, lba_packet
    mov ah, 0x42
    mov dl, byte [bsDriveNumber]
    int 0x13
    jnc read_disk_raw.endf
    ERROR VBR_ERROR_DISK_READ_ERR
 .endf:
    pop si
    ret
 ; Data
 ; #############
 ;
 ; Locals
 ;
 ; #############
 ; offset from the begining of sector 0 to the active partition.
 partition_offset:
    dw 0x0000
 %assign bytes_remaining (420 - ($ - $$))
 %warning VBR has bytes_remaining bytes remaining for code (MAX: 420 bytes)
 times (510 - ($ - $$)) nop     ; Fill the rest of sector with nop
 BootSig:
    dw 0xAA55                    ; Add boot signature at the end of bootloader
Author	SHA1	Message	Date
Elaina Claus	578e9934d8	more bug catching after changing the location of data also cleanup comment from previous bug	2024-12-19 18:59:34 -05:00
Elaina Claus	2a6792ae01	moved varibles passed from vbr to .data section this is to work around having to save them without .bss ready	2024-12-19 15:18:28 -05:00
Elaina Claus	2c5e5ccbee	might have fixed some of the boot_drive issues with ext_read	2024-12-19 13:13:46 -05:00
Elaina Claus	a830191547	added carry and divz checks across the fat32 code also use the pointers we have in bss to our saved data	2024-10-16 11:58:57 -04:00
Elaina Claus	38bcd93ced	some debuging text for fat32 stuff	2024-10-15 20:37:49 -04:00
Elaina Claus	f1842d0cbc	remove some redundant reloads of si use xchg to swap si/di instead of the stack uninline ClusterToLBA call	2024-10-15 20:01:24 -04:00
Elaina Claus	e085cbbab7	remove jmp short init at the start of stage2 also correct total size output as combined .data + .text	2024-10-15 18:33:57 -04:00
Elaina Claus	915ac4c8ae	align to 16 byte bounds and add git info to build	2024-10-15 18:28:06 -04:00
Elaina Claus	e65220fece	correct size of operand in PrintDWORD added some magic debug points for stuff that isn't working as well.	2024-10-15 13:32:36 -04:00
Elaina Claus	6731e03e38	magic debug before touching anything in error printer	2024-10-15 13:31:51 -04:00
Elaina Claus	47a47051b2	turn off magic debug in mbr/vbr stages	2024-10-15 13:31:32 -04:00
Elaina Claus	8e2ca06406	removed bpb_offset_bx dep reworked init: process 512 byte stack...should be more than enough for the vbr	2024-10-15 12:57:54 -04:00
Elaina Claus	2b9d0d9946	moved stack to end of bss & reduced size for now. removed redzone label reordered sp/bp setup and bss zeroing in init: fixed kmemcpy call stack usage	2024-10-15 12:56:12 -04:00
Elaina Claus	1ce3f67263	reduced stack size in mbr stage removed some unused data in bss reordered how/when in init we set sp/bp and zero bss we now push the top of the stack pointer/bp at the top of the stack, which makes the stack frame more 'normal' also use movsb instead of movsw	2024-10-15 12:53:22 -04:00
Elaina Claus	f81f358987	include disk signature and reserved bytes in part table struct	2024-10-15 12:51:34 -04:00
Elaina Claus	41db11cc64	ha ha ha, again!	2024-10-15 12:51:02 -04:00
Elaina Claus	fd7754bc60	I guess wx work again on Debian Trixie?	2024-10-15 12:50:51 -04:00
Elaina Claus	0f04e682df	change entry points (again)	2024-10-14 17:58:43 -04:00
Elaina Claus	36fcb5faf0	16 KiB stage2	2024-10-14 17:58:30 -04:00
Elaina Claus	a5296bb438	correct drive_num argument on read_disk_raw	2024-10-14 13:18:41 -04:00
Elaina Claus	933cccb88e	replace text documentation with markdown	2024-10-14 10:44:44 -04:00
Elaina Claus	ad2d37c63b	use bochs magic breakpoints in the error printer makes it easier to get a good state to do some investigating before reseting.	2024-10-13 20:53:13 -04:00
Elaina Claus	f32745a7e3	enable magic in the normal bochsrc.txt	2024-10-13 20:51:34 -04:00
Elaina Claus	8537d6cd5e	use bx addressing in read_disk_raw	2024-10-13 20:51:16 -04:00
Elaina Claus	e57c2cc67d	Merge pull request #3 from Nivirx/bss-setup convert MBR, VBR, & Stage2 to use a BSS section.	2024-10-13 18:05:19 -04:00
Elaina Claus	e4b9c5d77f	added partition_table and fat32_bpb params to stage2 also the partition table and fat32_bpb and passed/copied from the mbr/vbr now	2024-10-13 17:54:06 -04:00
Elaina Claus	e3a646675f	bss for vbr stage	2024-10-13 17:52:28 -04:00
Elaina Claus	9d33469e32	fixed bss init in mbr	2024-10-13 17:52:09 -04:00
Elaina Claus	dd1a74bff0	pass location of partition_table structure to vbr	2024-10-13 16:41:39 -04:00
Elaina Claus	29db27925f	initial work on a macro to call read_disk_raw	2024-10-13 16:37:52 -04:00
Elaina Claus	7f06d47f32	add reserved space for jmp short init at the start, technically this is part of the bpb anyways	2024-10-13 16:37:29 -04:00
Elaina Claus	4faffbf7fe	remove defs for memory locations (moving to bss)	2024-10-13 16:36:55 -04:00
Elaina Claus	832141efb4	bss convertion for mbr stage	2024-10-13 16:36:11 -04:00
Elaina Claus	c919144496	turns out huge unreal mode isn't supported in bochs huge unreal mode is 4GiB code in 16bit mode + 4GiB data we will just use the regular big flat model instead (64KiB code/4GiB data)	2024-10-13 14:50:49 -04:00
Elaina Claus	a62f3de26f	unreal gdt tweaks & fixes	2024-10-13 13:22:01 -04:00
Elaina Claus	0983ec3fd5	remove map files as well	2024-10-12 22:16:17 -04:00
Elaina Claus	bd40d6d324	relocate code sections to end up with stage2 starting at 0x500	2024-10-12 22:14:47 -04:00
Elaina Claus	3d3bcc6ea5	reduced stage2 to 24KiB	2024-10-12 22:13:12 -04:00
Elaina Claus	d1f8ec4a9e	follow standard proceedure and reallocate the mbr to 0x600	2024-10-12 21:21:43 -04:00
Elaina Claus	2fa03c31d7	partially roll back changing the segment to 0x07E0	2024-10-12 20:25:04 -04:00
Elaina Claus	f535840572	big step...and also its completely broken right now we are going to use 0x07E0 as our base segment so we have a bit more memory to work with until we are fully in 32bit protected mode. this commit is broken but is just one step towards a working release.	2024-10-12 15:41:39 -04:00
Elaina Claus	54b7a81648	correct typo	2024-10-12 15:39:16 -04:00
Elaina Claus	1d84f52690	definition corrections in part table stuff	2024-10-12 15:39:04 -04:00
Elaina Claus	276fe70572	use early_mem.inc	2024-10-12 15:38:47 -04:00
Elaina Claus	73b42c66fd	renamed mem.inc and removed unused items	2024-10-12 15:38:24 -04:00
Elaina Claus	9656a9465b	first version of kmemcpy5/kmemset4	2024-10-12 14:48:26 -04:00
Elaina Claus	bd80f48b1b	use NASM defined size value from structure macro	2024-10-12 12:58:32 -04:00
Elaina Claus	3fbfcbef53	BIOSMemoryMap is a location in bss now, use lea	2024-10-12 12:58:16 -04:00
Elaina Claus	31c45051e6	minor cleanup related to memory refactor	2024-10-12 12:57:56 -04:00
Elaina Claus	a523e17d27	moved stuff that is only referenced in Stage2 to stage2 bss	2024-10-12 12:55:29 -04:00
Elaina Claus	65e5a83eb4	stage2 is now a multisection binary file also preparing to move memory globals to bss section.	2024-10-12 11:29:20 -04:00
Elaina Claus	cd048933ec	output symbol maps to ease debuging	2024-10-12 11:28:25 -04:00
Elaina Claus	e648fd0de6	remove PRINT_FUNC macro...this isn't it chief	2024-10-12 11:27:55 -04:00
Elaina Claus	2581e50c8b	ignore nasm symbol map files	2024-10-12 11:27:20 -04:00
Elaina Claus	60aaf5cdd9	move far jump setup in EnterUnrealMode to right after we save CS	2024-10-11 21:51:07 -04:00
Elaina Claus	59678149e0	added debug config for bochs	2024-10-11 21:49:15 -04:00
Elaina Claus	075e51c8bc	move macro definition super early fix a few mistakes in macro defs	2024-10-11 19:31:31 -04:00
Elaina Claus	48cd0f742d	added macros to define cstr and str aligned all the entry points for proceedures to 4 bytes added a PrintString wraper macro	2024-10-11 19:05:15 -04:00
Elaina Claus	e5fb1b41eb	added bochs debug wrappers	2024-10-11 19:03:27 -04:00
Elaina Claus	208729ed01	split e820 bios call documentation to its own file under docs/	2024-10-11 17:20:53 -04:00
Elaina Claus	086cf9d8ea	correct src size in op	2024-10-11 16:52:57 -04:00
Elaina Claus	095822fa27	inlined ClusterToLBA removed caller save kludge for now init first_root_dir_sector from ebpb data	2024-10-11 15:55:24 -04:00
Elaina Claus	71f13fd6b5	somewhat of a cludge, but added a macro to save all caller saved regs	2024-10-11 14:25:01 -04:00
Elaina Claus	802d47fbf7	fix passing stage2 wrong data for boot drive	2024-10-11 13:09:17 -04:00
Elaina Claus	4af0637c7f	use kmemset to 0 out fat32_state in InitFATDriver	2024-10-11 13:00:45 -04:00
Elaina Claus	07197b0d5b	reduce proceedure local storage to 16 bytes	2024-10-11 12:59:36 -04:00
Elaina Claus	056551fdd1	rename file to BOOT.BIN K.I.S.S.	2024-10-11 12:16:01 -04:00
Elaina Claus	0aae0616fd	more comments to seperate setups	2024-10-11 12:08:09 -04:00
Elaina Claus	aff631f3db	force 1-1 logical to physical sectors copy our VBR code to backup VBR	2024-10-11 12:04:44 -04:00
Elaina Claus	a3a768adf4	more error handling in detecting disk image creation will need ported to macOS sometime	2024-10-11 11:44:04 -04:00
Elaina Claus	d684d4f11f	more error handling for dd writes	2024-10-11 11:31:38 -04:00
Elaina Claus	75c046f9cd	use gs for vesa framebuffer (was fs)	2024-10-08 20:23:16 -04:00
Elaina Claus	00daf92df5	unreal gdt now has 2 selectors 1 code, 1 data ss, and e/f/g segments are loaded to the same flat 4gb segment moved gdt notes to documentation	2024-10-08 20:22:21 -04:00
Elaina Claus	5ab7e70455	Update README.md	2024-10-08 09:08:47 -04:00
Elaina Claus	6ae68d1a19	ensure 2 byte jmp rel8 thunk to init surpress reloc abs warnings corrected include paths/filenames	2024-10-08 08:55:17 -04:00
Elaina Claus	586f3f0106	converted error handler to a 16bit far jump optimized the early error printer a bit to save some bytes removed DEBUG_HCF macro	2024-10-08 08:53:30 -04:00
Elaina Claus	8301fc20a8	renamed files to show code vs defs files that actually include code should be in .nasm files defines/macros/non-code should be in .inc files	2024-10-07 20:41:15 -04:00
Elaina Claus	4218a08658	force the first jump to init in all stages to be the rel8 version	2024-10-07 20:39:39 -04:00
Elaina Claus	2bbdaddb68	jmp imm32 vs jmp rel8 (5 bytes vs 2 bytes)	2024-10-06 21:46:32 -04:00
Elaina Claus	213ea11209	cutting out everything from miniboot this file has always just been a place holder to get some code to load from the disk I wanted to cut out all the extra stuff in it just to simplify things down.	2024-10-06 18:52:20 -04:00
Elaina Claus	e41b597056	surpress some of the relocation warnings for mbr, vbr & stage2	2024-10-06 18:50:32 -04:00
Elaina Claus	f33ecbcea2	make the Linux bochs run more inline with the Windows one	2024-10-06 15:37:19 -04:00
Elaina Claus	03a09ed54b	Merge pull request #2 from Nivirx/FAT_Refactor Full refactor for modularization	2024-10-05 20:19:51 -04:00
Elaina Claus	145e9fbaa9	fixed read_disk_raw in ReadFATCluster boot_drive and partition_offset are global pointers now removed an extra error from mbr disk read and some general formating and cleanup 😅	2024-10-05 20:14:00 -04:00
Elaina Claus	8f95c8f267	tons more work on modularizing the code	2024-10-05 18:55:00 -04:00
Elaina Claus	5440a1ae61	more modularization and updating date in MIT licence header	2024-10-05 13:35:39 -04:00
Elaina Claus	d6af15a7a6	typo fix	2024-10-05 12:16:31 -04:00
Elaina Claus	a4fa48949c	Move fat32 and BIOS functions to their own files	2024-10-05 12:04:40 -04:00
Elaina Claus	0a1123c5b5	removed extra part probe and added sleep before removing disk also back to putting the test 32bit mode code on the root of the volume	2024-10-05 10:14:02 -04:00
Elaina Claus	e162e268c4	remove the dword stack macros and just use the 32bit override	2024-10-05 10:13:18 -04:00
Elaina Claus	62f036b645	change test kernel stage name also pointed up a bug in memory.inc	2024-10-04 22:17:35 -04:00
Elaina Claus	fdbfd811d5	increased disk size and moved bpb/ebpb a bit	2024-10-04 14:26:10 -04:00
Elaina Claus	d93236d298	some bpb/ebpb tweaks	2024-10-04 11:48:25 -04:00
Elaina Claus	86fd76e909	remove old kmem functions	2024-10-04 09:57:32 -04:00
Elaina Claus	3f029e6b4c	vbr cdecl overhaul refactored read_disk_raw to read_stage2_raw switched to new kmem functions	2024-10-04 09:56:41 -04:00
Elaina Claus	30c4f1b82c	move cdecl macros to nearly the top so early functions can use them	2024-10-04 09:55:45 -04:00
Elaina Claus	597132df9f	cdecl16 overhaul for mbr code switch to cdecl kmem* functions refactored read_disk_raw to read_vbr_raw fixed a small issue where the mbr wasn't checking its signature	2024-10-04 09:55:19 -04:00
Elaina Claus	63e6f1fac8	kmemset and kmemcpy cdecl16 versions	2024-10-04 09:53:01 -04:00
Elaina Claus	4ee766304b	seperate error code for reading disk in mbr vs vbr vs stage2	2024-10-04 09:52:24 -04:00
Elaina Claus	d5aa70daf3	add macros to prevent __CDECL16 stuff from being defined multiple times	2024-10-04 09:51:44 -04:00
Elaina Claus	ec1f40c305	added isoz stage to make a compressed disk image also included a work around for a WSL bug in create-disk.sh	2024-10-04 07:57:56 -04:00
Elaina Claus	36e3bd968a	change FAT partition type to 0Ch from 0Bh (W95 FAT32 LBA was CHS/LBA)	2024-10-03 21:00:49 -04:00
Elaina Claus	36b8869140	add bpb and ebpb reserve area back to vbr.nasm	2024-10-03 21:00:02 -04:00
Elaina Claus	41b9bf5134	remove this and add it back to vbr.nasm	2024-10-03 20:59:25 -04:00
Elaina Claus	b96f587921	add forked functions and remove from memory.inc for kmem*	2024-10-03 19:53:11 -04:00
Elaina Claus	89ebe30ad8	forking kmemset functions for stage2 usage	2024-10-03 19:52:24 -04:00
Elaina Claus	e98cc41403	forking kmemset functions to be updated later for mbr/vbr	2024-10-03 19:52:00 -04:00
Elaina Claus	27c41c8b0a	update some of the dword stack macros	2024-10-03 19:33:07 -04:00
Elaina Claus	015def8d52	rough pass on fixing the stack across the board	2024-10-03 19:02:47 -04:00
Elaina Claus	8157dd301c	swap order of entering Unreal mode and getting an E820 also InitFATDriver should be ok to add to the start process again.	2024-10-03 18:15:18 -04:00
Elaina Claus	4d05d2ae4c	move E820 function desc to memory.inc	2024-10-03 18:14:04 -04:00
Elaina Claus	de5b0ddc5d	cdecl16 update for EnterUnrealMode	2024-10-03 17:59:29 -04:00
Elaina Claus	2cfe86efac	refactored and validated MemoryMap funciton	2024-10-03 17:41:48 -04:00
Elaina Claus	c8ca94d7ba	some general cleanup & moving the halt to the next point in main()	2024-10-03 16:43:10 -04:00
Elaina Claus	ac6110aa40	cdecl16 work and cleanup in MemoryMap	2024-10-03 16:34:27 -04:00
Elaina Claus	46717935a1	src/stage2/stage2.nasm:573: warning: label alone on a line without a colon might be in error [-w+label-orphan]	2024-10-03 15:28:44 -04:00
Elaina Claus	f691000a31	cdecl16 for EnableA20 ver.1	2024-10-03 15:10:22 -04:00
Elaina Claus	c524d8801d	replace prologs and epilogs in cdecl functions so far	2024-10-03 14:51:43 -04:00
Elaina Claus	0084747765	added entry & exit macros	2024-10-03 14:46:47 -04:00
Elaina Claus	929962eaca	bunch of changes mostly to do with cdecl16 conformity moved top of stack marker to init SetTextMode and Cursor done before hello msg corrected CC/Stack usage to conform with cdecl16 for PrintString corrected CC/Stack usage to conform with cdecl16 for PrintChar corrected stack usage to conform with cdecl16 for SetTextMode corrected stack usage to conform with cdecl16 for disable_cursor	2024-10-03 13:49:44 -04:00
Elaina Claus	054f4320ba	fixing how the stack works stage1 😳	2024-10-02 12:37:21 -04:00
Elaina Claus	2f6bd2e2d8	remove comment about CC, see docs/	2024-10-02 11:59:34 -04:00
Elaina Claus	7c446ef3b2	load our base headers in the same order as the mbr	2024-10-02 10:26:36 -04:00
Elaina Claus	2bbfa0931b	moved reservation for bpb to a include	2024-10-02 10:25:59 -04:00
Elaina Claus	8e595e8eba	added some clarification on cdecl16	2024-10-02 10:13:45 -04:00
Elaina Claus	5e4e40f7de	removed ata1 from windows bochsrc	2024-10-02 10:13:00 -04:00
Elaina Claus	6db97e3258	added bxrc config to launch on windows hosts	2024-09-21 14:09:52 -04:00
Elaina Claus	d42ee1df60	small optimization to error printer saves us 5 bytes of code (15 overall)	2024-09-21 13:45:15 -04:00
Elaina Claus	96a8103e11	added debuging 'errors' also there is special handling for them in error.inc	2024-09-21 13:28:52 -04:00
Elaina Claus	a5702bd92e	partially revert change, sti is still in init	2024-09-21 12:32:49 -04:00
Elaina Claus	bdc1fc5bf0	added -P option to losetup this fixes an issue that appeared on WSL2 recently(ish)	2024-09-21 12:04:05 -04:00
Elaina Claus	1c27b665b0	ignore vscode personal configs	2024-09-21 11:46:36 -04:00
Elaina Claus	abc79adeb7	remove reallocation in mbr init also reenable interupts in the init block	2024-09-21 11:45:22 -04:00
Elaina Claus	7fd4a89d96	Update README.md updated description to more accurately reflect project status	2024-07-27 09:21:41 -04:00
Elaina Claus	355ceb49a7	changed extention from .s to .nasm	2023-08-23 10:10:30 -04:00
Elaina Claus	b590edd3ff	enable logging and bump to 128MB of memory	2023-08-23 10:10:13 -04:00
Elaina Claus	30b71d2e6e	updated gitignore	2023-08-23 10:09:49 -04:00
Elaina Claus	b2857ff9fd	clarify that WSL is supported	2023-08-23 07:35:30 -04:00
Elaina Claus	4e9e58c430	added description for create-disk script	2023-08-22 16:45:22 -04:00
Elaina Claus	5916b46a9e	Update README.md	2023-08-22 16:34:39 -04:00
Elaina Claus	d162d5dc4c	update readme with more information	2023-08-22 16:22:13 -04:00
Elaina Claus	d4dc46d770	MIT license applied to all project files	2023-08-22 16:03:46 -04:00
Elaina Claus	ad828ac1f4	use wx interface for config, gui, and debug	2023-08-22 15:56:15 -04:00
Elaina Claus	5fdde61dd3	remove packaged binaries	2023-08-22 15:55:45 -04:00
Elaina Claus	90ced63cba	small changes to License 🏳️‍⚧️	2023-08-22 14:24:35 -04:00
Elaina Claus	2c55ed5c04	Update README.md	2023-08-22 10:43:54 -04:00
Elaina Claus	94a2fb08ca	Delete COPYING Removing GPL-3.0 license.	2023-08-22 10:43:01 -04:00
Elaina Claus	b9850f7ab9	Create README.md	2023-08-22 10:36:35 -04:00
Elaina Claus	f181f21e41	Merge pull request #1 from Xinnx/add-license-1 Create LICENSE.md	2023-02-28 22:24:40 -05:00
Elaina Claus	309a5fb95c	Create LICENSE.md	2023-02-28 22:24:32 -05:00