Adds strlen()

src/core.asm

@@ -4,6 +4,11 @@ section .text
 	global	exit
 
 ;----- exit(exit_code) -----;
+; Exits the program with given exit code
+; Return value: N/A
+; Used registers:
+;	rax*	syscall
+;	rdi	(arg) code to exit the program with
 exit:
 	mov	rax, NR_exit
 	syscall