libasm/ft_write.s

extern __errno_location

section .text
	global ft_write

ft_write:
	mov rax, 1 ; syscall write, other arguments should be good accord to calling convention
	syscall
	cmp eax, -1 ; linux syscalls errors are always in the range -4095 to -1
	jg .done
	cmp eax, -4095
	jl .done
	mov rbx, rax ; save return value of syscall
	call __errno_location WRT ..plt ; put address of errno in rax
	neg rbx ; errno should be positive
	mov [rax], rbx ; set errno
	mov rax, -1 ; set return value of ft_write to -1
	ret

.done:
	ret