.code16
.global _start

.equ STACK_SEGMENT, 0x7C00
.equ ORG_SEGMENT, 0x0

.text
_start:
                cli
                jmp $ORG_SEGMENT, $(asmain)
asmain:

                xor %ax, %ax
                mov %ax, %ds
                mov %ax, %es
                mov %ax, %ss

                mov $STACK_SEGMENT, %esp

                mov $0xDEAD, %ax
                call printRegister
                call putSeparator

                mov $0xDEAD, %ax
                call printRegister
                call putSeparator

                mov $0xDEAD, %ax
                call printRegister
                call putSeparator

                mov $0xDEAD, %ax
                call printRegister
                call putSeparator

stop:           jmp stop



printChar:
                mov $0xE, %ah # interrupt service
                mov $0x3, %bh # BH = page number = 0 ; BL = 3 = Cyan (ignored)
                int $0x10
                ret

putSeparator:
                mov $'_', %al
                call printChar
                ret

printRegister:
                test %ax, %ax # test for 0, that would
                jne .go
                mov $'0', %al
                call printChar
                ret

.go:
                mov $10, %bx
                xor %cx, %cx # number of elements pushed.
                xor %dx, %dx # high part of dividend
.loop:
                div %bx     # result = %AX ; remaineder = %DX

                # we're not done yet:
                # Increment n. of elements
                add $1, %cx  # elements to show

                add $0x30, %dx # convert to ASCII
                push %dx

                test %ax, %ax # should we continue?
                je .show

                # Prepare %AX for next divs.
                xor %dx, %dx
                jmp .loop

.show:
                pop %dx

                mov %dl, %al # load character -- already printable
                call printChar

                sub $1, %cx
                test %cx, %cx
                jnz .show

                ret

.space 510 - (. - _start)
.word 0xaa55