segment .note.GNU-stack

extern __errno_location

section .text
	global ft_read

ft_read:
	cmp rsi, 0				; check if the buffer is NULL
	je .exit				; if true go to exit
	mov rax, 0				; syscall 0 is for read
	syscall					; call the system call read
	cmp rax, 0				; check if the return value of syscall
	jl .error				; jump if the syscall return less than 0 
	jmp .exit				; jump to exit

.error:
	mov rdi, rax			; stock errno value in rdi
	neg rdi					; errno value in positive (index used by C function)
	call __errno_location	; rax = &errno
	mov [rax], edi			; stock the errno return in the address of rax
	mov rax, -1				; set the value of rax to -1
	jmp .exit				; jump to exit

.exit:
	ret						; return rax value