From 31c45051e6b6b6576f49e2e9ff71caa7ded44550 Mon Sep 17 00:00:00 2001
From: Elaina Claus <elaina.claus@chtm.me>
Date: Sat, 12 Oct 2024 12:57:56 -0400
Subject: [PATCH] minor cleanup related to memory refactor

---
 src/mbr/mbr.nasm | 23 ++---------------------
 src/vbr/vbr.nasm | 16 +++++++++-------
 2 files changed, 11 insertions(+), 28 deletions(-)

diff --git a/src/mbr/mbr.nasm b/src/mbr/mbr.nasm
index cfec883..efb5e84 100755
--- a/src/mbr/mbr.nasm
+++ b/src/mbr/mbr.nasm
@@ -25,14 +25,11 @@
 [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"
@@ -43,11 +40,7 @@ nop
 %include "error_codes.inc"
 %include "partition_table.inc"
 
-; ###############
-; End Section
-; ###############
-
-ALIGN 4, db 0x90
+ALIGN 4
 init:
     cli                         ; We do not want to be interrupted
 
@@ -69,23 +62,15 @@ init:
     jmp 0:main
 
 ; ###############
-;
 ; Extra/Shared Functions
-;
 ; ###############
 
 %include "util/kmem_func.nasm"
 %include "util/error_func.nasm"
 
-; ###############
-; End Section
-; ###############
-
 ;
 ; 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
@@ -158,7 +143,7 @@ main:
 
         mov si, word [bp - 4]
         mov dl, byte [bp - 2]
-        jmp 0:0x7C00
+        jmp word 0x0000:0x7C00
 
 ; ###############
 ;
@@ -168,10 +153,6 @@ main:
 
 %include 'BIOS/func/ext_read.nasm'
 
-; ###############
-; End Section
-; ###############
-
 %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
diff --git a/src/vbr/vbr.nasm b/src/vbr/vbr.nasm
index 009f7ae..c68a37b 100755
--- a/src/vbr/vbr.nasm
+++ b/src/vbr/vbr.nasm
@@ -24,7 +24,7 @@
 [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
@@ -51,11 +51,8 @@ times 54 db 0x00
 %include "error_codes.inc"
 %include "fat32/bpb_offset_bx.inc"
 
-; ###############
-; End Section
-; ###############
 
-ALIGN 4, db 0x90
+ALIGN 4
 init:
     cli                         ; We do not want to be interrupted
 
@@ -85,6 +82,9 @@ init:
 ; End Section
 ; ###############
 
+;
+; byte boot_drive @ bp - 2
+; word part_offset @ bp - 4
 ALIGN 4, db 0x90
 main:
     mov byte [bp - 2], dl            ; boot_drive
@@ -101,7 +101,7 @@ main:
     push ax
     mov ax, fat32_bpb                                  ; defined in memory.inc, destination
     push ax
-    call kmemcpy                                       ; copy bpb to memory
+    call kmemcpy                                       ; copy bpb & ebpb to memory
     add sp, 0x6
 
     mov bx, fat32_bpb                                  ; bx now points to aligned memory structure
@@ -130,6 +130,8 @@ main:
     add sp, 0xC
 
 .check_sig:
+    ; BUG: this is hard coded to check @ ((0x7E0 << 4) + 0x7FFC)...i.e (STAGE2_ENTRY + (STAGE2_MAX_BYTES - 4))
+    ; this should be removed or done properly
     mov ax, 0x7E0
     mov fs, ax
     cmp dword [fs:0x7FFC], 0xDEADBEEF
@@ -140,7 +142,7 @@ main:
 .sig_ok:
     mov si, word [bp - 4]
     mov dl, byte [bp - 2]
-    jmp 0:0x7E00
+    jmp word 0x0000:0x7E00
 
 ; ###############
 ; Required BIOS function(s)