in out

x86-64/in-out/in-out.asm

@@ -4,8 +4,22 @@ segment readable executable
 
 entry $
 	; read from stdin
-	xor		rax, rax
+	xor		rax, rax		; is rax and rax equal to itself? yes? rax is set to 0 (for sys_read)
+	xor		rdi, rdi		; same thing but rdi (for stdin)
+	mov 	rsi, buf		; direct addressing - move address of buf to rsi (buffer address)
+	mov 	rdx, 80			; buffer size
+	syscall
 
+	; write to stdout
+	mov 	rax, 1			; sys_write
+	mov 	rdi, 1			; stdout
+	mov 	rdx, 80
+	syscall
+
+	; exit program
+	xor		rdi, rdi		; exit code 0
+	mov 	rax, 60			; sys_exit
+	syscall
 
 segment readable writable
 buf 	rb 80