Add printf() comment, return length of printed message

console.asm

@@ -46,6 +46,8 @@ puts:
 	leave
 	ret
 ;----- printf(const char* string, ...) -----;
+; Currently only supports specifiers: %d, %c, %s
+; Return value: Amount of printed characters
 printf:
 	push	rbp
 	mov	rbp, rsp
@@ -213,6 +215,8 @@ printf:
 	mov	byte [r11], 0x0
 	lea	rdi, [rel printfBuff]
 	call	print
+	lea	rdi, [rel printfBuff]
+	call	strlen
 
 	pop	r13
 	pop	r12