diff --git a/x86/aes-encrypt.asm b/x86/aes-encrypt.asm
index 3570092ad55d0f9ade487bc0a41f38b19d9f67d0..34f21b3ba7d49fc578d4ca1e36a10b1d61e5af1c 100644
--- a/x86/aes-encrypt.asm
+++ b/x86/aes-encrypt.asm
@@ -50,7 +50,7 @@ aes_encrypt:
 	C src = 32(%esp)
 
 	movl	24(%esp), %ebp
-	cmpl	$0, %ebp
+	testl	%ebp,%ebp
 	jz	.Lencrypt_end
 	
 .Lencrypt_block_loop: