[bits 16]
[org 0x7c00]
mov bp, 0x8000
mov sp, bp

mov bx, rdd
call print
call print_nl

mov bx, 0x9000
mov dh, 2

call disk_load

mov dx, [0x9000]
mov bx, ok
call print
call print_nl
mov bx, nxt
call print
call print_nl

call print_hex
call print_nl

jmp 0x9000
jmp $

disk_load:
    pusha
    push dx

    mov ah, 0x02 ;INT 0x13 read mode
    mov al, dh
    mov cl, 0x02 ;Sector
    mov ch, 0x00 ;Cylinder
    mov dh, 0x00 ;Head

    int 0x13
    jc disk_error

    pop dx
    cmp al, dh

    jne sectors_error
    popa
    ret

disk_error:
    mov bx, diskerror
    call print
    call print_nl
    jmp $

sectors_error:
    mov bx, sectorerror
    call print
    jmp $

print:
    pusha

start:
    mov al, [bx]
    cmp al, 0
    je done

    mov ah, 0x0e
    int 0x10

    add bx, 1
    jmp start

done:
    popa
    ret


print_nl:
    pusha

    mov ah, 0x0e
    mov al, 0x0a
    int 0x10
    mov al, 0x0d
    int 0x10

    popa
    ret

print_hex:
    pusha

    mov cx, 0

hex_loop:
    cmp cx, 4
    je end

    mov ax, dx
    and ax, 0x000f
    add al, 0x30
    cmp al, 0x39
    jle step2
    add al, 7

step2:
    mov bx, HEX_OUT + 5
    sub bx, cx
    mov [bx], al
    ror dx, 4

    add cx, 1
    jmp hex_loop

end:
    mov bx, HEX_OUT
    call print

    popa
    ret

HEX_OUT db '0x0000',0
ok db "[OK] Stage 2 sectors loaded",0
nxt db "[SB] Executing stage 2...",0
rdd db "[SB] Reading disk...",0
diskerror db "[ER] Disk error",0
sectorerror db "[ER] Sector error",0

times 510-($-$$) db 0
dw 0xaa55

mov al, 0Eh
mov ax, 'A'
int 10h