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[org 0x7C00]
%define KSTART 0x7E00
%define KSECTORS (KSIZE + 511) / 512
boot:
; init segment registers
xor ax, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
; init stack
mov bp, KSTART ; stack grows down, overwriting MBR
mov sp, bp
; print message
mov ebx, .msg
call print_str
; load stage2 and stage3
call load_stages
; jump into stage2
jmp KSTART
.msg: db 10, 13, "nyax stage1", 10, 13, 0
load_stages:
mov ebx, .msg
call print_str
mov ah, 0x02 ; read sectors from drive
mov al, KSECTORS ; number of sectors
xor ch, ch ; cylinder=0
mov cl, 2 ; sector=2
xor dh, dh ; head=0
mov bx, KSTART ; buffer
int 0x13
jc .fail ; CF set on error
cmp al, KSECTORS ; check read sectors count
jne .fail
ret
.fail:
mov ebx, .fail_msg
call print_str
hlt
.msg: db "loading stage2 and stage3 from disk", 10, 13, 0
.fail_msg: db "disk failure, try rebooting", 10, 13, 0
%include "stage1/print.asm"
times 510-($-$$) db 0
dw 0xAA55
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