Correct prefetch hint in power7 memrchr

Alan Modra amodra@gmail.com
Tue Mar 25 02:04:00 GMT 2014


Typo fix.  Discovered when looking at some disassembly, and wondering
why this disassembled as dcbtt.  My simple benchmark testing didn't
show any effect of using the wrong hint, but at a guess you'd only see
a difference on a very long memrchr with cold caches.

	* sysdeps/powerpc/powerpc64/power7/memrchr.S: Correct stream hint.

diff --git a/sysdeps/powerpc/powerpc64/power7/memrchr.S b/sysdeps/powerpc/powerpc64/power7/memrchr.S
index 40e436f..0c01ca2 100644
--- a/sysdeps/powerpc/powerpc64/power7/memrchr.S
+++ b/sysdeps/powerpc/powerpc64/power7/memrchr.S
@@ -29,7 +29,7 @@ ENTRY (__memrchr)
 	mr	r10,r3
 	clrrdi	r6,r7,7
 	li	r9,3<<5
-	dcbt	r9,r6,16      /* Stream hint, decreasing addresses.  */
+	dcbt	r9,r6,8       /* Stream hint, decreasing addresses.  */
 
 	/* Replicate BYTE to doubleword.  */
 	insrdi	r4,r4,8,48

-- 
Alan Modra
Australia Development Lab, IBM



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