diff --git a/crypto/rc4/asm/rc4-x86_64.pl b/crypto/rc4/asm/rc4-x86_64.pl
index 4b990cba077e21ac5233724af0e1f1d9d1045dcf..5236afec12b173a642274caf34169b5d04a057eb 100755
--- a/crypto/rc4/asm/rc4-x86_64.pl
+++ b/crypto/rc4/asm/rc4-x86_64.pl
@@ -221,6 +221,8 @@ $code.=<<___;
 	movb	$TY#b,($dat,$XX[0])
 	add	$TX[0]#b,$TY#b
 	add	\$1,$XX[0]#b
+	movzb	$TY#b,$TY#d
+	movzb	$XX[0]#b,$XX[0]#d
 	movzb	($dat,$TY),$TY#d
 	movzb	($dat,$XX[0]),$TX[0]#d
 	xorb	($inp),$TY#b