bits 16				; mode 16bits
org 0x7C00			; mbr ae loaded at 0x7C00

jmp boot

display_enable:
    push bp
    mov bp, sp
    mov ah, 0h      ; 00h    Set Video Mode
    mov al, 07h     ; Txt, monochrome, 80x25

    int 10h

    mov sp, bp
    pop bp
    ret

print:
    push bp
    mov bp, sp
    mov si, [bp + 4]; put first function arg in si. sp is stask pointer
.loop:
    lodsb           ; load si content into al then inc si
    cmp al, 0;
    je .end

    mov ah, 0eh
    mov bx, 0
    int 10h

    jmp .loop

.end:
    mov sp, bp
    pop bp
    ret

println:
    push bp
    mov bp, sp
    push word [bp + 4]
    call print
    add sp, 2

    mov ah, 03h     ; read cursor position
    int 10h         ; row number in dh. Col in dl

    inc dh          ; goto next line
    mov dl, 0

    mov ah, 02h     ; Set Cursor Position
    int 10h
    mov sp, bp
    pop bp
    ret

hello db 'Hello world', 0
name db 'This is a name', 0

boot:
    sti             ; enable virtual interupts

    call display_enable

    push hello
    call println
    add sp, 2

    push name
    call println
    add sp, 2

times 510 - ($ - $$) db 0	; fill up to 510 with 0
dw 0xAA55			; MBR magic number