diff options
Diffstat (limited to 'bootloader.asm')
| -rw-r--r-- | bootloader.asm | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/bootloader.asm b/bootloader.asm index 0abf90f..8270cd6 100644 --- a/bootloader.asm +++ b/bootloader.asm @@ -48,6 +48,14 @@ org 0x7c00 mov es, ax sti +read_cmdline: + + mov eax, 0x0001 ; load one sector + xor bx, bx ; no offset + mov cx, 0x1e00 ; load Kernel command line at 0x1e000 + mov esi, cmd_lba + call read_from_hdd + read_kernel_bootsector: mov eax, 0x0001 ; load one sector @@ -83,10 +91,6 @@ set_header_fields: mov byte [es:0x227], 0x01 ; set ext_loader_type (bootloader id: 0x11) mov dword [es:0x228], 0x1e000 ; set cmd_line_ptr cld ; copy cmd_line - mov si, cmd_line - mov di, 0xe000 - mov cx, cmd_length - rep movsb read_protected_mode_kernel: @@ -118,6 +122,7 @@ read_protected_mode_kernel_2: .next: xor bx, bx mov cx, 0x2000 + mov esi, current_lba call read_from_hdd mov ecx, edx shr ecx, 1 @@ -135,15 +140,20 @@ run_kernel: mov sp, 0xe000 jmp 0x1020:0 + ;; read_from_hdd: + ;; ax: count in 512-byte sectors [1, 127] + ;; bx: destination: offset + ;; cx: destination: segment + ;; esi: lba pointer (typically current_lba) read_from_hdd: push edx mov [dap.count], ax mov [dap.offset], bx mov [dap.segment], cx - mov edx, [current_lba] + mov edx, [esi] mov [dap.lba], edx - add [current_lba], eax ; update current_lba + add [esi], eax ; update current_lba mov ah, 0x42 mov si, dap mov dl, 0x80 ; first hard disk @@ -222,10 +232,7 @@ dap: dd 0 ; low bytes of LBA address dd 0 ; high bytes of LBA address -current_lba dd 7620608 ; initialize to first LBA address -cmd_line db 'root=/dev/sda1', 0 -cmd_length equ $ - cmd_line error_msg db 'err', 0 ; /* FIXME: newline */ -; times 510-($-$$) db 0 -; dw 0xaa55 +current_lba dd 8218 ; initialize to first LBA address +cmd_lba dd 8218 ; initialize to LBA address of cmdline.txt |