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From: Prakhar Bahuguna <prakhar.bahuguna@arm.com>
To: newlib@sourceware.org
Cc: nd@arm.com
Subject: [PATCH, ARM] Fix minor issues in memchr NEON implementation
Date: Fri, 02 Jun 2017 10:23:00 -0000	[thread overview]
Message-ID: <20170602102256.eyeslc2gyznswpvl@e107464-lin.cambridge.arm.com> (raw)

[-- Attachment #1: Type: text/plain, Size: 477 bytes --]

The NEON-optimised implementation of memchr has a couple of minor issues - it
does not mask off the higher bits of the input character, and it uses a signed
comparison instead of unsigned within the smallstr loop. This patch addresses
both of these issues.

ChangeLog:

2017-06-02  Prakhar Bahuguna  <prakhar.bahuguna@arm.com>

	* libc/machine/arm/memchr.S: Add and instruction to mask off all but
	the lowest byte.
	Change blt to blo.

Okay for master?

-- 

Prakhar Bahuguna

[-- Attachment #2: 0001-Fix-minor-issues-in-memchr-NEON-implementation.patch --]
[-- Type: text/plain, Size: 924 bytes --]

From ac13527b4d7a5f91088920c59bc53b0a771858e1 Mon Sep 17 00:00:00 2001
From: Prakhar Bahuguna <prakhar.bahuguna@arm.com>
Date: Fri, 2 Jun 2017 10:22:32 +0100
Subject: [PATCH] Fix minor issues in memchr NEON implementation

---
 newlib/libc/machine/arm/memchr.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/newlib/libc/machine/arm/memchr.S b/newlib/libc/machine/arm/memchr.S
index b5dcf83c0..7c22b117e 100644
--- a/newlib/libc/machine/arm/memchr.S
+++ b/newlib/libc/machine/arm/memchr.S
@@ -135,10 +135,11 @@ memchr:
 	/* Use a simple loop if there are less than 8 bytes to search.  */
 	cmp	cntin, #7
 	bhi	.Llargestr
+	and	chrin, chrin, #0xff
 
 .Lsmallstr:
 	subs	cntin, cntin, #1
-	blt	.Lnotfound	/* Return not found if reached end.  */
+	blo	.Lnotfound	/* Return not found if reached end.  */
 	ldrb	tmp, [srcin], #1
 	cmp	tmp, chrin
 	bne	.Lsmallstr	/* Loop again if not found.  */
-- 
2.13.0


             reply	other threads:[~2017-06-02 10:23 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-02 10:23 Prakhar Bahuguna [this message]
2017-06-07 10:16 ` Corinna Vinschen

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