use16
org 0x7c00
main:
    jmp 0x0:entry
entry:
    mov sp, 0
    mov ss, sp

    mov bx, hello_message
    call write_message

    jmp load_tail
    jmp $

hello_message:
    db 'Hello ', 0
recalibration_message:
    db 'Recalibrating ', 0
shit_happened_message:
    db 'Shit happened ', 0

load_tail:
    mov bx, recalibration_message
    call write_message

    mov ah, 00h
    mov dl, 00h
    int 013h
    jc load_tail
    mov ah, 02h
    xor al, 1
    xor ch, ch
    mov cl, 2
    xor dh, dh
    mov di, system
    mov es, di
    xor bx, bx
    int 013h
    jnc system
    mov bx, shit_happened_message
    push
    call write_message
    call print_floppy_error
    jmp $


print_floppy_error:
    mov ah, 01h
    int 013h

    mov al, ah
    ror al, 4
    and al, 0Fh
    call print_hex

    mov al, ah
    and al, 0Fh
    call print_hex
    return:
        ret

print_hex:
    cmp al, 9
    ja add_65
    add_60:
        add al, 030h
        jmp print
    add_65:
        add al, 040h
        sub al, 10
    print:
    call print_char
    ret

print_char:
    mov ah, 0Eh
    int 010h
    ret


write_message:
    mov ah, 0Eh
    ;xor bh, bh
    start:
        mov al, [bx]
        or al, al
        jz end
        push bx
        xor bx, bx
        int 10h
        pop bx
        inc bx
        jmp start
    end:
    ret

gdtr:
    dw 0, 0
    dw 0, 0

    dw 0FFFFh, 0000h
    db 0h, 09Ah, 0C0h, 0

    dw 0FFFFh, 0000h
    db 0h, 092h, 0CFh, 0

padding:
    times 510-$+$$ db 0
    db 055h
    db 0AAh

system:
    mov bx, second_hello_message
    call write_message

second_hello_message:
    db 'Second hello', 0