From e40d4748cd19d89435ba6a00e2859f7d0e892009 Mon Sep 17 00:00:00 2001
From: Raphael <rparodi@student.42.fr>
Date: Thu, 11 Dec 2025 23:11:49 +0100
Subject: [PATCH] feat(write): adding the write function in asm

---
 src/ft_write.s | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 src/ft_write.s

diff --git a/src/ft_write.s b/src/ft_write.s
new file mode 100644
index 0000000..c1218be
--- /dev/null
+++ b/src/ft_write.s
@@ -0,0 +1,21 @@
+segment .note.GNU-stack
+extern __errno_location
+
+section .text
+	global ft_write
+
+ft_write:
+	mov rax, 1				; syscall 1 is for write
+	syscall					; call the system call write
+	cmp rax, 0				; check if the return value of syscall
+	jl .error				; jump if the return value is less than 0 
+	ret						; return the value of the syscall
+
+.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
+	ret						; return with -1 (and errno value)
+