; **************************************************************************** ;
;                                                                              ;
;                                                         :::      ::::::::    ;
;    ft_write.s                                         :+:      :+:    :+:    ;
;                                                     +:+ +:+         +:+      ;
;    By: cacharle <marvin@42.fr>                    +;+  +:+       +;+         ;
;                                                 +;+;+;+;+;+   +;+            ;
;    Created: 2019/11/22 03:04:47 by cacharle          ;+;    ;+;              ;
;    Updated: 2019/11/22 21:19:02 by cacharle         ;;;   ;;;;;;;;.fr        ;
;                                                                              ;
; **************************************************************************** ;

global _ft_write

%define F_GETFD 1
%define SYSCALL_WRITE 0x2000004
%define SYSCALL_FCNTL 0x200005c

; int ft_write(int rdi, const void *rsi, size_t rdx);
_ft_write:
	cmp  rdx, 0
	je   FT_WRITE_NO_SIZE
	cmp  rdi, 0
	jl   FT_WRITE_ERROR    ; fd < 0
	cmp  rsi, 0
	je   FT_WRITE_ERROR    ; buf == NULL

	push rdx
	push rsi
	xor  rsi, rsi
	mov  esi, F_GETFD
	mov  rax, SYSCALL_FCNTL 
	syscall
	pop  rsi
	pop  rdx
	cmp  eax, 0
	jne  FT_WRITE_ERROR

	mov  rax, SYSCALL_WRITE
	syscall
	ret
FT_WRITE_ERROR:
	mov  rax, -1
	ret
FT_WRITE_NO_SIZE:
	mov  rax, 0
	ret