From 420be8df92533bfbd56861dada670045720ba633 Mon Sep 17 00:00:00 2001
From: alc <alc@FreeBSD.org>
Date: Sun, 10 Apr 2005 18:12:07 +0000
Subject: Eliminate a conditional branch and as a side-effect eliminate a
 branch to a return instruction.  (The latter is discouraged by the Opteron
 optimization manual because it disables branch prediction for the return
 instruction.)

Reviewed by: bde
---
 lib/libc/amd64/string/bcmp.S | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

(limited to 'lib')

diff --git a/lib/libc/amd64/string/bcmp.S b/lib/libc/amd64/string/bcmp.S
index bb72035..36a0c7e 100644
--- a/lib/libc/amd64/string/bcmp.S
+++ b/lib/libc/amd64/string/bcmp.S
@@ -6,7 +6,6 @@ __FBSDID("$FreeBSD$");
 #endif
 
 ENTRY(bcmp)
-	xorl	%eax,%eax		/* clear return value */
 	cld				/* set compare direction forward */
 
 	movq	%rdx,%rcx		/* compare by words */
@@ -19,7 +18,7 @@ ENTRY(bcmp)
 	andq	$7,%rcx
 	repe
 	cmpsb
-	je	L2
-
-L1:	incl	%eax
-L2:	ret
+L1:
+	setne	%al
+	movsbl	%al,%eax
+	ret
-- 
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