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;; boot.stage1.asm
%include "boot.common.asm"
%include "boot.stage1.print.asm"
[org 0x7c00]
[bits 16]
%define READ_SECTORS_NUM 64
%define BOOT_LOAD_ADDR 0x7c00
%define SECTOR_SIZE 512
entry _start
_start:
;; Disable interrupts
cli
;; Setup segment registers
xor ax, ax
mov ds, ax
mov es, ax
mov ss, ax
;; Adjust Stack
mov sp, _start
mov si, [disk_addr_packet]
mov ah, 0x42 ; BIOS extended read function
mov dl, 0x80 ; Drive number
int 0x13 ; BIOS disk services
jc _disk_read_err
jmp 0x0000:0x7e00
_disk_read_err:
hlt
jmp _disk_read_err
_end:
hlt
jmp _end
disk_read_err_msg: db "Failed to read disk", 13, 10, 0
disk_read_success_msg: db "Read the disk successfully", 13, 10, 0
disk_addr_packet:
db 0x10
db 0x0
DAP_sectors_num:
dw READ_SECTORS_NUM ; Number of read sectors
dd (BOOT_LOAD_ADDR + SECTOR_SIZE) ; Destination address
dq 1 ; First sector after the boot sector
;; Padding and magic number
times 510 - ($ - $$) db 0
dw 0xaa55
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