small clarification on what "unreal" mode really is

but now I need to write an arena allocator...so brb

.gitea/workflows/onpush.yaml

@@ -0,0 +1,40 @@
+name: Daily Build and trunk tester
+on:
+  push:
+    branches: [ $default-branch ]
+  pull_request:
+    branches: [ $default-branch ]
+  schedule:
+    - cron: "0 7 * * *"   # daily 07:00
+  workflow_dispatch: {}
+
+jobs:
+  debian_update:
+    runs-on: debian-trixie
+    steps:
+      - name: Checkout (if needed)
+        uses: actions/checkout@v4
+
+      - name: Install CHTM apt cache endpoint into container
+        run: |
+          echo 'Acquire::http::Proxy "http://chtm-aptcache-01.lan.chtm.me:3142";' | tee /etc/apt/apt.conf.d/01aptproxy
+      
+      - name: Ensure image is up to date and install build tools and deps
+        run: |
+          bash -c "apt update && apt upgrade -y"
+          apt install -y build-essential nasm mtools fdisk dosfstools 
+
+      - name: Build stevia
+        run: make
+
+      - name: Upload build artifacts
+        if: always()   # still keep logs/artifacts even if build fails
+        uses: actions/upload-artifact@v3
+        with:
+          name: stevia-${{ github.run_number }}
+          path: |
+            build/output/artifacts.tar.gz
+            build/output/disk.img.gz
+            build/output/part.img.gz
+          if-no-files-found: error
+          retention-days: 30   # override server default if you like

.github/workflows/daily.yaml

@@ -0,0 +1,35 @@
+name: Daily Build and trunk tester
+on:
+  push:
+    branches: [ $default-branch ]
+  schedule:
+    - cron: "0 7 * * *"   # daily 07:00
+  workflow_dispatch: {}
+
+jobs:
+  debian_update:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout (if needed)
+        uses: actions/checkout@v4
+      
+      - name: Update and install build tools and deps
+        run: |
+          sudo bash -c "apt update && apt upgrade -y"
+          sudo apt install -y build-essential nasm mtools fdisk dosfstools 
+
+      - name: Build stevia
+        run: make
+
+      - name: Upload build artifacts
+        if: always()   # still keep logs/artifacts even if build fails
+        uses: actions/upload-artifact@v4
+        with:
+          name: stevia-${{ github.run_number }}
+          path: |
+            build/output/artifacts.tar.gz
+            build/output/disk.img.gz
+            build/output/part.img.gz
+          if-no-files-found: error
+          retention-days: 7   # override server default if you like
+          

.gitignore

@@ -1,7 +1,8 @@
-out/*
 build/*
+build/output/*
 *.img
 *.img.gz
+*.img.gz
 *.elf
 bx_enh_dbg.ini
 stevia-log

LICENSE.md

@@ -1,14 +0,0 @@
-Copyright (C) 2025 Elaina Claus
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <https://www.gnu.org/licenses/>.

Makefile

@@ -32,8 +32,8 @@ 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)"'
 
-iso := '/tmp/disk.img'
+iso := 'build/disk.img'
-isoz := 'disk.img.gz'
+isoz := 'build/output/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
@@ -45,10 +45,11 @@ stage2: $(stage2_binary_files)
 boottest: $(boottest_binary_files)
 
 clean:
-	@rm -rvf *.map
+	@rm -v $(build_dir)/*.bin
-	@rm -rvf $(build_dir)/*
+	@rm -v $(build_dir)/*.map
-	@rm -rvf $(iso)
+	@rm -v $(build_dir)/*.img
-	@rm -rvf $(isoz)
+	@rm -v $(build_dir)/output/*.img.gz
+	@rm -v $(build_dir)/output/*.tar.gz
 
 run: $(iso)
 	@sudo qemu-system-i386 $(qemu_args) -hda $(iso)
@@ -79,8 +80,7 @@ build/%.bin: src/miniboot32/%.nasm
 	@nasm -i$(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...
+	@scripts/create-disk.sh
-	@sudo scripts/create-disk.sh
 
 $(isoz): $(iso)
 	@gzip -9kc $(iso) > $(isoz)

README.md

@@ -67,4 +67,4 @@ We welcome contributions! Feel free to open issues for bugs or feature requests,
 
 ## License
 
-This project is licensed under the MIT License. See the [LICENSE](LICENSE) file for more details.
+This project is licensed under the GPLv3 License. See the [LICENSE](LICENSE.md) or [COPYING](COPYING) file for more details.

bochsrc.txt

@@ -1,7 +1,7 @@
 # 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: wx
+display_library: x, 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"
@@ -10,7 +10,7 @@ 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=lba
+ata0-master: type=disk, path="./build/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

include/BIOS/func/E820_memory_map.nasm

@@ -40,23 +40,27 @@ GetMemoryMap:
 .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]
+    mov 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 ecx, AddressRangeDescStruct_t_size  ; hard request ACPI 3.0 table versions (24 bytes)
-    mov edx, 0x534D4150                     ; 'SMAP' magic
+    
 .loop_L1:
+    mov eax, 0x0000E820                     ; select 0xE820 function
+    mov edx, 0x534D4150                     ; 'SMAP' magic
     int 0x15
     jc GetMemoryMap.error
     cmp eax, 0x534D4150
     jne GetMemoryMap.no_smap_returned
 .no_error:
-    inc dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
+    mov eax, dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
+    add eax, 1
+    mov dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries], eax
 
     cmp ecx, 20                             ; TODO: maybe this could be handled better than just panicing
     jb GetMemoryMap.nonstandard_e820        ; non-standard entry found 
@@ -64,9 +68,11 @@ GetMemoryMap:
     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
+    ; setup for next loop, ebx is our next index and has already been set.
-    mov edx, eax                            ; 'SMAP' to edx
+    xor ecx, ecx
-    mov eax, 0xE820                         ; select E820 function
+    mov ecx, AddressRangeDescStruct_t_size  ; set ecx (requested_size) to 24 bytes
+    add di, cx                              ; increment di to next descriptor so es:di points to the next free space
+
     jmp GetMemoryMap.loop_L1
 .error:
     ERROR STAGE2_MM_E820_MISC_ERR
@@ -79,5 +85,37 @@ GetMemoryMap:
     __CDECL16_EXIT
     ret
 
+PrintMemoryMap:
+    __CDECL16_ENTRY
+.func:
+    mov eax, dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
+    cmp eax, 0
+    je PrintMemoryMap.endp          ; if entries == 0, exit
+
+    mov ecx, eax                    ; store # of entries in counter
+    mov eax, BIOSMemoryMap          ; address to start of e820 mmap
+
+    push dword ecx
+    push dword eax
+    call FormatMemoryMapEntry
+    add sp, 0x8
+
+    ; ax contains segment offset to string after call
+    ; TODO: going to need an allocator for strings and stuff...
+    ; print_string strformat_buffer
+    
+.endp:
+    __CDECL16_EXIT
+    ret
+
+FormatMemoryMapEntry:
+    __CDECL16_ENTRY
+.func:
+    ; create a string buffer somewhere and return address to result string in ax
+.endp:
+    __CDECL16_EXIT
+    ret
+
+
 %endif
 %define __INC_E820MEMORY_MAP

include/fat32/FAT32_SYS.inc

@@ -32,7 +32,7 @@ InitFATDriver:
     mov ax, fat32_state
     push ax                     ; address of structure
     call kmemset
-    sub sp, 0x6
+    add sp, 0x6
 
 .calc_active_part:
     mov ax, word [partition_offset]            
@@ -146,7 +146,7 @@ SearchFATDIR:
         xor ax, ax
         push ax                 ; segment
         call ReadFATCluster     ; uint8_t ReadFATCluster(uint16_t seg, uint16_t offset, uint32_t cluster)
-        sub sp, 0x8
+        add 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
@@ -221,7 +221,7 @@ NextCluster:
     mov ax, fat32_nc_data
     push ax                     ; address of structure
     call kmemset
-    sub sp, 0x6
+    add sp, 0x6
 
     mov edx, dword [bp + 4]
     mov si, fat32_nc_data                        ; instead of push/pop and moving the data back

include/util/arena_alloc.nasm

@@ -0,0 +1,100 @@
+%ifndef __INC_ARENA_ALLOC_FUNC
+
+%define __ARENA_HEAP_START 0x8000
+%define __ARENA_HEAP_SIZE  0x6000   ; 0x8000 -> 0xE000 = 24KiB of Heap
+
+struc ArenaStateStruc_t
+    .start resw 1
+    .end resw 1
+    .mark resw 1
+endstruc
+
+; void arena_init(ArenaState *a)
+;
+arena_init:
+    __CDECL16_ENTRY
+.func:
+    movzx eax, word [bp + 4]     ; ptr to state structure
+    mov di, ax
+
+    xor eax, eax
+    mov word [di + ArenaStateStruc_t.mark], eax
+    mov word [di + ArenaStateStruc_t.end], word (__ARENA_HEAP_START + __ARENA_HEAP_SIZE)
+    mov word [di + ArenaStateStruc_t.start], __ARENA_HEAP_START
+
+    ; zero out heap area on init
+    ; void* kmemset_byte(void* dst, uint8_t val, uint16_t len);
+    mov ax, __ARENA_HEAP_SIZE
+    push ax                     ; len
+    xor ax, ax
+    push ax                     ; val = 0
+    mov ax, __ARENA_HEAP_START
+    push ax                     ; dst
+    call kmemset
+    add sp, 0x6
+
+.endp:
+    __CDECL16_EXIT
+    ret
+
+; size_t align_up(size_t x, size_t a)
+; ax, bx. cx are all clobbered
+; align x up to the nearest specified alignment (a), a should be a power of 2
+; (x + (a-1)) & ~(a-1)
+; return value in ax
+arena_align_up:
+    __CDECL16_ENTRY
+.func:
+    
+    mov ax, [bp + 4]      ; x
+
+    mov bx, [bp + 6]      
+    sub bx, 1             ; a - 1
+
+    mov cx, ax
+    add cx, bx            ; x + (a+1)
+    not bx                ; ~(a-1)
+
+    and cx, bx            ; and with the inverse
+
+    mov ax, cx            ; move to ax and return
+.endp:
+    __CDECL16_EXIT
+    ret
+
+; void* arena_alloc(void* a, size_t bytes, size_t align)
+arena_alloc:
+    __CDECL16_ENTRY
+.func:
+    ; remove bytes from pool and increment mark to the new cursor location
+    ; return a pointer to the begining of  allocated segment
+.endp:
+    __CDECL16_EXIT
+    ret
+
+arena_mark:
+    __CDECL16_ENTRY
+.func:
+    ; return the current location of the 'cursor' in the allocator
+.endp:
+    __CDECL16_EXIT
+    ret
+
+arena_reset_to:
+    __CDECL16_ENTRY
+.func:
+    ; rewind the arena to a previously marked point
+.endp:
+    __CDECL16_EXIT
+    ret
+
+arena_reset:
+    __CDECL16_ENTRY
+.func:
+    ; reset the entire heap to a fresh state
+.endp:
+    __CDECL16_EXIT
+    ret
+
+%endif
+%define __INC_ARENA_ALLOC_FUNC

scripts/create-disk.sh

@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+set -euo pipefail
 
 # Copyright (C) 2025 Elaina Claus
 # 
@@ -15,8 +16,8 @@
 #     You should have received a copy of the GNU General Public License
 #     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-if ! [ $(id -u) = 0 ]; then
+if [ $(id -u) = 0 ]; then
-   echo "Script must be run as root!" >&2
+   echo "Script should not be run as root, it could break something! Exiting!" >&2
    exit 1
 fi
 
@@ -26,235 +27,143 @@ vbr_file=build/vbr.bin
 stage2_file=build/stage2.bin
 boottest_file=build/BOOTi686.bin
 
-
 # Disk creation options
-mount_point=/tmp/stevia_disk
+disk_img=build/disk.img
-disk_tmp_file=/tmp/disk.img
+disk_img_final=build/output/disk.img.gz
-disk_file_final=./disk.img.gz
+
+part_img=build/part.img
+part_img_final=build/output/part.img.gz
+
+artifacts_archive=build/output/artifacts.tar.gz
 
 # $disk_sector_size * $disk_size = total bytes, default is 256MiB
-disk_size=(524288 * 2)
+disk_sectors=(524288 * 2)
 disk_sector_size=512
+part_start=2048
+part_sectors=$((disk_sectors - part_start))
 
-if ! [ -e $disk_tmp_file ]; then
+#
+# Build sanity section
+#
+
+echo "*** Performing pre-build sanity checks ***"
+
+# Tools needed:
+#   sfdisk dosfstools (mkfs.fat), mtools (mcopy,mmd), gzip, dd, truncate, awk
+for t in mcopy mmd gzip dd truncate awk; do
+  command -v "$t" >/dev/null || { echo "Missing tool: $t" >&2; exit 1; }
+done
+
+# these are normally in the sbin paths so I've had issues detecting them with command -v
+SF=$(command -v sfdisk || echo /usr/sbin/sfdisk)
+MKFS=$(command -v mkfs.fat || echo /usr/sbin/mkfs.fat)
+
+[[ -x "$SF" ]] || { echo "sfdisk not found"; exit 1; }
+[[ -x "$MKFS" ]] || { echo "mkfs.fat not found"; exit 1; }
+
+# check that required build files exist
+for f in "$mbr_file" "$vbr_file" "$stage2_file" "$boottest_file"; do
+  [[ -f "$f" ]] || { echo "missing $f" >&2; exit 1; }
+done
+
+cat > /tmp/pt.sfdisk <<EOF
+label: dos
+unit: sectors
+sector-size: $disk_sector_size
+label-id: 0xa0b0c0d0
+
+start=$part_start, size=$((disk_sectors - part_start)), type=c, bootable
+EOF
+
+mtool_src=/tmp/mtools.conf
+cat > $mtool_src <<EOF
+drive c: file="$part_img"
+EOF
+
+#
+# Create disk images
+#
+
+echo "[1/7] Create disk.img and part.img"
+
+if ! [ -e "$disk_img" ]; then
     # create raw disk image
-    if ! dd if=/dev/zero of=$disk_tmp_file bs=$disk_sector_size count=$disk_size; then
+    if ! truncate -s $((disk_sectors * disk_sector_size)) "$disk_img"; then
         echo "Failed creating blank disk image." >&2
         exit 1
     fi
     sync
 else
     echo "Removing old disk image..."
-    rm -rfv $disk_tmp_file
+    rm -rfv "$disk_img"
-    if ! dd if=/dev/zero of=$disk_tmp_file bs=$disk_sector_size count=$disk_size; then
+    if ! truncate -s $((disk_sectors * disk_sector_size)) "$disk_img"; then
         echo "Failed creating blank disk image." >&2
         exit 1
     fi
     sync
 fi
 
-if [[ "$OSTYPE" == "linux-gnu"* ]]; then
+if ! [ -e "$part_img" ]; then
-        if [ -e $mbr_file ] && [ -e $vbr_file ]; then
+    # create raw partition disk image
-        # get next loop device and mount it
+    if ! truncate -s $((part_sectors * disk_sector_size)) "$part_img"; then
-        ld=$(losetup -f)
+        echo "Failed creating blank partition image." >&2
-        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 $ld < scripts/loop_setup.sfdisk
-
-        # get first partition, this is sloppy might need to review this...
-        firstpart=$(lsblk -ilp -o NAME $ld | tr '\n' ' ' | awk '{print $3}')
-        mkfs.fat -v -F32 -s 1 -n 'STEVIAFS' $firstpart
-
-        #
-        # MBR setup
-        #
-
-        # copy MBR while preserving partition table
-        if ! dd if=$mbr_file of=$ld bs=1 count=440; then
-            echo "Failed to write MBR to disk. (part 1)" >&2
-            exit 1
-        fi
-
-        # copy MBR 0xAA55
-        if ! dd if=$mbr_file of=$ld bs=1 seek=510 skip=510 count=2; then
-            echo "Failed to write MBR to disk. (part 2)" >&2
-            exit 1
-        fi
-
-        #
-        # VBR Setup & backup VBR
-        # 
-
-        # copy VBR to partition 1 while preserving partition information
-        # copy jmp short entry; nop
-        if ! dd if=$vbr_file of=$firstpart bs=1 count=3; then
-            echo "Failed to write VBR to disk. (part 1)" >&2
-            exit 1
-        fi
-        # copy bootcode
-        if ! dd if=$vbr_file of=$firstpart bs=1 seek=90 skip=90 count=420; then
-            echo "Failed to write VBR to disk. (part 2)" >&2
-            exit 1
-        fi
-        # copy 0xAA55
-        if ! dd if=$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
-        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
-            mkdir $mount_point
-        fi
-        mount $firstpart $mount_point
-
-        # ensure mountpoint is actually a mountpoint
-        if ! mountpoint -q $mount_point; then
-            echo "Failed to mount partition at $mount_point." >&2
-            exit 1
-        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
-        # BUG: ${logname}:$(id $(logname -g)) doesn't work right on WSL because of runlevel hacks in WSL
-        # 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 $disk_tmp_file
-
-    else
-        echo "unable to find MBR/VBR binaries!" >&2
         exit 1
     fi
-# requires util-linux from homebrew
+    sync
-elif [[ "$OSTYPE" == "darwin"* ]]; then
+else
-        sfdisk_path="/usr/local/opt/util-linux/sbin/sfdisk"
+    echo "Removing old (partition) disk image..."
-        if [ -e $mbr_file ] && [ -e $vbr_file ]; then
+    rm -rfv "$part_img"
-        # use hdiutil to attach our empty disk image
+    if ! truncate -s $((part_sectors * disk_sector_size)) "$part_img"; then
-        ld_path_raw=$(hdiutil attach -readwrite -imagekey diskimage-class=CRawDiskImage -nomount -blocksize 512 -noverify /tmp/disk.img)
+        echo "Failed creating blank partition image." >&2
-        ld=$(echo $ld_path_raw | sed s:/dev/::)
+        exit 1
-        ld_path="/dev/$ld"
-
-        # create a DOS disk, with 1 FAT32 partition
-        if ! [ -e $sfdisk_path ]; then
-            echo "sfdisk utility was not found...We cannot use diskutil to make disks due to the fact that it only makes Hybrid MBR's & GPT disks...blame Apple"
-            exit 4
-        else
-            $sfdisk_path $ld_path < scripts/loop_setup.sfdisk
-        fi
-
-        # give stuff a chance to settle, macOS has problems here
-        sync
-        sleep .5
-
-        # reattch the raw image file since macOS doesn't have a partprobe...
-        # this is the only way I know to get macOS to reprobe the disk
-        hdiutil eject $ld
-        unset ld_path
-        unset ld
-        unset ld_path_raw
-
-        ld_path_raw=$(hdiutil attach -readwrite -imagekey diskimage-class=CRawDiskImage -nomount -blocksize 512 -noverify /tmp/disk.img)
-        ld=$(echo $ld_path_raw | grep "FDisk_partition_scheme" | awk '{print $1}' | sed s:/dev/::)
-        ld_path="/dev/$ld"
-
-        if ! [ -b /dev/$ld ]; then
-            echo "Unable to remount disk! exitting before I do some damage!"
-            exit 5
-        fi
-
-        # get first partition and format as FAT32
-        firstpart=$(diskutil list $ld | grep 1: | awk '{print $6}')
-        firstpart_direct="r$firstpart"
-
-        newfs_msdos -F 32 /dev/$firstpart_direct
-        sync
-        
-        # copy MBR while preserving partition table
-        dd if=$mbr_file of=$ld_path bs=1 count=440 conv=sync
-        # copy MBR 0xAA55
-        dd if=$mbr_file of=$ld_path bs=1 seek=510 skip=510 count=2 conv=sync
-
-        # copy VBR to partition 1 while preserving partition information
-        # copy jmp short entry; nop
-        dd if=$vbr_file of=/dev/$firstpart bs=1 count=3 conv=sync
-        # copy bootcode
-        dd if=$vbr_file of=/dev/$firstpart bs=1 seek=90 skip=90 count=420 conv=sync
-        # copy 0xAA55
-        dd if=$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=$ld_path bs=$disk_sector_size seek=1 conv=sync
-
-        #sync pending dd stuff
-        sync
-
-        # copy boot32 boot test file to disk image
-        if ! [ -e $mount_point ]; then
-            mkdir $mount_point
-        else
-            echo "$mount_point exists! clearing contents..."
-            rm -rfv $mount_point
-            mkdir $mount_point
-        fi
-        mount -t msdos /dev/$firstpart $mount_point
-
-        if [ -e $boottest_file ]; then
-            cp -v $boottest_file $mount_point
-        else
-            echo "unable to find boot32.bin!"
-            exit 3
-        fi
-
-        # detach loop device
-        sync
-        umount /dev/$firstpart
-        hdiutil eject $ld
-
-        # chown to the real user to prevent issues with reading/writing the file later
-        SUDOUSER=$(logname)
-        chown ${SUDOUSER}:staff disk.img
-        gzip -9kc $disk_tmp_file > $disk_file_final
-    else
-        echo "unable to find MBR/VBR binaries!"
-        exit 2
     fi
+    sync
+fi
+
+
+if [[ "$OSTYPE" == "linux-gnu"* ]]; then
+        echo "[2/7] Write DOS partition table (single FAT32 LBA @ 2048)"
+        "$SF" --no-reread "$disk_img" < /tmp/pt.sfdisk
+
+        echo "[3/7] Make FAT32 filesystem in partition image"
+        "$MKFS" -v -F32 -s 1 -n 'STEVIAFS' "$part_img"
+
+        echo "[4/7] Patch VBR inside partition image (preserve BPB)"
+
+        # copy jmp short entry; nop
+        dd if=$vbr_file of="$part_img" bs=1 count=3 conv=notrunc
+        # copy bootcode
+        dd if=$vbr_file of="$part_img" bs=1 seek=90 skip=90 count=420 conv=notrunc
+        # copy signature (should be 0xAA55)
+        dd if=$vbr_file of="$part_img" bs=1 seek=510 skip=510 count=2 conv=notrunc
+
+        # copy backup VBR within the created partition image
+        # Linux dosfstools will complain (read: not work) unless this is done it seems
+        # HACK: sector 6 is the **default** location of the BPB_BkBootSec, it **can** be different.
+        dd if="$part_img" of="$part_img" bs=$disk_sector_size count=1 seek=6 conv=notrunc
+
+        echo "[5/7] Copy boot payload to FAT32 filesystem using mtools as BOOT.BIN"
+        MTOOLSRC="$mtool_src" mcopy "$boottest_file" C:BOOT.BIN
+        MTOOLSRC="$mtool_src" mdir C:
+
+        echo "[6/7] Patch MBR and install stage2 loader to disk image"
+        # patch MBR+signature while preserving partition table
+        dd if="$mbr_file" of="$disk_img" bs=1 count=440 conv=notrunc
+        dd if="$mbr_file" of="$disk_img" bs=1 seek=510 skip=510 count=2 conv=notrunc
+
+        # copy stage2 to absolute LBA 1
+        dd if="$stage2_file" of="$disk_img" bs=$disk_sector_size seek=1 conv=notrunc
+
+        echo "[7/7] Assembling final disk image"
+        # place partition at it's place in the disk image
+        dd if="$part_img" of="$disk_img" bs=$disk_sector_size seek=$part_start conv=notrunc
+
+        echo " *** Outputing disk images will be in ./build/output/* *** "
+        gzip -9c "$disk_img" > "$disk_img_final"
+        gzip -9c "$part_img" > "$part_img_final"
+        tar caf "$artifacts_archive" build/*.bin build/*.map
 else
         # Unknown.
-        echo "Unknown OS type! Supported build hosts systems are GNU/Linux (WSL) and macOS."
+        echo "Unknown OS type! Supported build hosts systems are GNU/Linux (& WSL)"
         exit 1
 fi

scripts/loop_setup.sfdisk

@@ -1,5 +0,0 @@
-label: dos
-unit: sectors
-sector-size: 512
-
-start=        2048, type=c, bootable

src/mbr/mbr.nasm

@@ -18,7 +18,7 @@
 [CPU KATMAI]
 [WARNING -reloc-abs-byte]
 [WARNING -reloc-abs-word]                   ; Yes, we use absolute addresses. surpress these warnings.
-[map all mbr.map]
+[map all build/mbr.map]
 %define __STEVIA_MBR
 jmp short (init - $$)
 nop

src/stage2/stage2.nasm

@@ -16,7 +16,7 @@
 [BITS 16]
 [ORG 0x0500]                            ; IF YOU CHANGE ORG CHANGE THE SIGN OFFSET AT THE END
 [CPU KATMAI]
-[map all stage2.map]
+[map all build/stage2.map]
 [WARNING -reloc-abs-byte]
 [WARNING -reloc-abs-word]
 [WARNING -reloc-abs-dword]              ; Yes, we use absolute addresses. surpress these warnings.
@@ -160,7 +160,7 @@ main:
     call GetMemoryMap
     print_string MemoryMap_OK_info
 
-    ; enter unreal mode
+    ; enter unreal mode (16 bit code, 32 bit flat memory model)
     call EnterUnrealMode
     print_string UnrealMode_OK_info
 
@@ -361,13 +361,13 @@ begin_data:
 %define CRLF 0Dh, 0Ah
 
 %macro define_cstr 2
-    ALIGN 16
+    align 16
     %1_cstr:
         db %2, 00h
 %endmacro
 
 %macro define_info 2
-    ALIGN 16
+    align 16
     %1_info:
         db %2, CRLF, 00h
 %endmacro
@@ -386,7 +386,7 @@ define_info MaybeFound_Boot, "Maybe found a file...checking..."
 
 define_cstr BootTarget, "BOOT    BIN"
 
-ALIGN 16, db 0
+align 16, db 0
 BootTarget:
     db 'BOOT    BIN'
 
@@ -394,28 +394,28 @@ BootTarget:
 ; pre-bss init globals (generally const...but there are exceptions)
 ;
 
-align 8, db 0x00
+align 8, db 0
 boot_drive:
     db 0x00
 
-align 8, db 0x00
+align 8, db 0
 partition_offset:
     dw 0x0000
 
-align 8, db 0x00
+align 8, db 0
 vbr_fat32_bpb_ptr:
     dw 0x0000
 
-align 8, db 0x00
+align 8, db 0
 vbr_part_table_ptr:
     dw 0x0000
 
-ALIGN 16
+align 16, db 0
 IntToHex_table:
     db '0123456789ABCDEF'
 
 ; see docs/gdt.txt for a quick refresher on GDT 
-ALIGN 16, db 0
+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)
@@ -438,7 +438,7 @@ unreal_gdt_start:
     db 0x00              ; Base Address(31:24)
 unreal_gdt_end:
 
-ALIGN 16, db 0
+align 16, db 0
 gdt32_info:
     gdt32_size: dw (gdt32_end - gdt32_start) - 1
     gdt32_ptr:  dd ((__STAGE2_SEGMENT << 4) + gdt32_start)
@@ -474,19 +474,19 @@ gdt32_start:
         db 0x00
 gdt32_end:
 
-ALIGN 8,db 0x00
+align 16,db 0
 BUILD_NASM_VER:
     db "Stevia Stage2 built with NASM - ", __NASM_VER__, 00h
 
-ALIGN 8,db 0x00
+align 16,db 0
 BUILD_DATETIME:
     db 'Assembled - ', __DATE__, ' ', __TIME__, 00h
 
-ALIGN 8,db 0x00
+align 16,db 0
 BUILD_GIT_VER:
     db __GIT_VER__, 00h
 
-ALIGN 8,db 0x00
+align 16,db 0
 BUILD_GIT_HASH:
     db __GIT_HASH__, 00h
 end_data:
@@ -504,24 +504,29 @@ section .bss follows=.sign
 begin_bss:
 ; structures
 
-align 8, resb 1
+align 16, resb 1
-partition_table resb PartTable_t_size
+partition_table: 
+    resb PartTable_t_size
 
-align 8, resb 1
+align 16, resb 1
-fat32_bpb resb FAT32_bpb_t_size
+fat32_bpb: 
-fat32_ebpb resb FAT32_ebpb_t_size
+    resb FAT32_bpb_t_size
+fat32_ebpb: 
+    resb FAT32_ebpb_t_size
 
-align 8, resb 1
+align 16, resb 1
-fat32_nc_data resb 16
+fat32_nc_data: 
+    resb 16
 
-align 8, resb 1
+align 16, resb 1
-lba_packet resb LBAPkt_t_size
+lba_packet: 
+    resb LBAPkt_t_size
 
-align 8, resb 1
+align 16, resb 1
 fat32_state:
     resb FAT32_State_t_size
 
-align 8, resb 1
+align 16, resb 1
 SteviaInfo:
     resd 4
 ;
@@ -541,12 +546,15 @@ dir_buffer:
 fat_fsinfo:
     resb 512
 
+; TODO: this will hold 42 entries from the map function
+; the e820 function needs to check that it doesn't overflow
+; but realisticly 42 entries is enough for dev work
 align 16, resb 1
-%define BIOSMemoryMap_SIZE 2048
+%define BIOSMemoryMap_SIZE 1024
 BIOSMemoryMap:
-    resb 2048
+    resb BIOSMemoryMap_SIZE
 
-align 512, resb 1
+align 16, resb 1
 stack_bottom:
     resb 1024
 stack_top:

src/vbr/vbr.nasm

@@ -17,7 +17,7 @@
 [CPU KATMAI]
 [WARNING -reloc-abs-byte]
 [WARNING -reloc-abs-word]
-[map all vbr.map]                   ; Yes, we use absolute addresses. surpress these warnings.
+[map all build/vbr.map]                   ; Yes, we use absolute addresses. surpress these warnings.
 %define __STEVIA_VBR
 section .text
 __ENTRY: