nivirx/stevia
1
0
Fork 0
Code Issues 1 Pull Requests Actions Packages Projects Releases 1 Wiki Activity

make space in bss directly for boot_drive and partition offsets

Browse Source
This commit is contained in:
Elaina Claus
2024-10-17 20:33:44 -04:00
parent 508bf1aa55
commit 520f877b05
1 changed files with 16 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
src/stage2/stage2.nasm
View File

@@ -121,22 +121,14 @@ struc EarlyBootStruct_t
.fat32_ebpb resb FAT32_ebpb_t_size .fat32_ebpb resb FAT32_ebpb_t_size
endstruc endstruc
; bp - 2 : byte boot_drive ; bp - 4 : ptr PartTable_t partition_table
; bp - 4 : word part_offset
; bp - 6 : ptr PartTable_t partition_table
; bp - 8 : ptr FAT32_bpb_t fat32_bpb ; bp - 8 : ptr FAT32_bpb_t fat32_bpb
ALIGN 4, db 0x90 ALIGN 4, db 0x90
main: main:
lea ax, [bp - 2] mov byte [boot_drive], dl ; boot_drive (probably 0x80)
mov [boot_drive_ptr], ax mov word [partition_offset], si ; partition_offset
mov word [bp - 4], bx ; partition_table_vbr
lea ax, [bp - 4] mov word [bp - 8], dx ; fat32_bpb_vbr
mov [partition_offset_ptr], ax ; setup pointers to boot_drive and partition offset on stack
mov byte [bp - 2], dl ; boot_drive (probably 0x80)
mov word [bp - 4], si ; partition_offset
mov word [bp - 6], bx ; partition_table_vbr
mov word [bp - 8], dx ; fat32_bpb_vbr
.check_sig: .check_sig:
mov eax, dword [STAGE2_SIG] mov eax, dword [STAGE2_SIG]
cmp eax, 0xDEADBEEF cmp eax, 0xDEADBEEF
@@ -145,20 +137,20 @@ main:
.stage2_main: .stage2_main:
mov ax, PartTable_t_size mov ax, PartTable_t_size
push ax push ax
mov ax, [bp - 6] ; ptr partition_table mov ax, [bp - 4] ; ptr partition_table
push ax push ax
mov ax, partition_table mov ax, partition_table
push ax push ax
call kmemcpy ; copy partition table data call kmemcpy ; copy partition table data
add sp, 0x6 add sp, 0x6
mov ax, (FAT32_bpb_t_size + FAT32_ebpb_t_size) ; size in byte mov ax, (FAT32_bpb_t_size + FAT32_ebpb_t_size) ; size in byte
push ax push ax
mov ax, [bp - 8] mov ax, [bp - 8]
push ax push ax
mov ax, fat32_bpb ; defined in memory.inc, destination mov ax, fat32_bpb ; defined in memory.inc, destination
push ax push ax
call kmemcpy ; copy bpb & ebpb to memory call kmemcpy ; copy bpb & ebpb to memory
add sp, 0x6 add sp, 0x6
call SetTextMode call SetTextMode
@@ -524,9 +516,12 @@ SteviaInfo:
; ;
; locals ; locals
; ;
boot_drive_ptr: ALIGN 4,resb 1
resw 1 boot_drive:
partition_offset_ptr: resb 1
ALIGN 4,resb 1
partition_offset:
resw 1 resw 1
; ;