asm-play/print_number.asm

%ifndef PRINT_NUMBER_ASM
%define PRINT_NUMBER_ASM

%include "syscalls.asm"

section .bss	align=8
print_num_buf	resb	64
print_num_buf_end:

section	.text
print_number:
	mov	r8, 0b001
	call	type_check
	
	;; extract the number
	shr	rax, 3

	;; fill the buffer up with the decimal version of the number

	;;; http://tptp.cc/mirrors/siyobik.info/instruction/CWD%252FCDQ%252FCQO.html
        mov	rsi, print_num_buf_end
        mov	rdi, 0
        mov	rbx, 10
        ;; cqo
.loop:
        mov	rdx, 0
        idiv	rbx             ; rax=quotient, rdx=remainder

        dec	rsi
        inc	rdi
        add	rdx, '0'
        mov	byte [rsi],dl
        
        test	rax, rax
        jnz	.loop

.done:
	mov	rdx, rdi

	;; print it
        mov     rax, sys_write
        mov     rdi, 1
        syscall

        ret

%endif