From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20613 invoked by alias); 12 Mar 2013 17:07:55 -0000 Received: (qmail 20596 invoked by uid 22791); 12 Mar 2013 17:07:51 -0000 X-SWARE-Spam-Status: No, hits=-3.0 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED,TW_MV,TW_XF X-Spam-Check-By: sourceware.org Received: from toast.topped-with-meat.com (HELO topped-with-meat.com) (204.197.218.159) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 12 Mar 2013 17:07:38 +0000 Received: by topped-with-meat.com (Postfix, from userid 5281) id A40F82C071; Tue, 12 Mar 2013 10:07:36 -0700 (PDT) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: "Joseph S. Myers" Cc: Richard Henderson , Subject: [PATCH 1/2 roland/arm-memchr] ARM: Change register allocation in armv6t2 memchr implementation. In-Reply-To: Joseph S. Myers's message of Tuesday, 12 March 2013 15:58:09 +0000 References: <20130311233120.C2F1B2C083@topped-with-meat.com> <513EC685.1020803@twiddle.net> Message-Id: <20130312170736.A40F82C071@topped-with-meat.com> Date: Tue, 12 Mar 2013 17:07:00 -0000 X-CMAE-Score: 0 X-CMAE-Analysis: v=2.1 cv=LYSvtFvi c=1 sm=1 tr=0 a=WkljmVdYkabdwxfqvArNOQ==:117 a=14OXPxybAAAA:8 a=N7b_zERDjVoA:10 a=Z6MIti7PxpgA:10 a=kj9zAlcOel0A:10 a=hOe2yjtxAAAA:8 a=wEedfx7CaSwA:10 a=pD5HHrBBZ7Pns1ofiGkA:9 a=ObXjPtGoCEpEtCB3:21 a=Gd8oCHGswCso2iTt:21 a=CjuIK1q_8ugA:10 X-IsSubscribed: yes Mailing-List: contact libc-ports-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: libc-ports-owner@sourceware.org X-SW-Source: 2013-03/txt/msg00115.txt.bz2 ports/ChangeLog.arm 2013-03-12 Roland McGrath * sysdeps/arm/armv6t2/memchr.S: Change register allocation so ldrd use is r4,r5 rather than r5,r6; this way ARM mode will allow that ldrd. --- a/ports/sysdeps/arm/armv6t2/memchr.S +++ b/ports/sysdeps/arm/armv6t2/memchr.S @@ -83,20 +83,20 @@ ENTRY(memchr) orr r1, r1, r1, lsl #8 @ expand the match word across to all bytes orr r1, r1, r1, lsl #16 - bic r4, r2, #7 @ Number of double words to work with * 8 + bic r6, r2, #7 @ Number of double words to work with * 8 mvns r7, #0 @ all F's movs r3, #0 15: - ldrd r5,r6, [r0],#8 - subs r4, r4, #8 - eor r5,r5, r1 @ Get it so that r5,r6 have 00's where the bytes match the target - eor r6,r6, r1 + ldrd r4,r5, [r0],#8 + subs r6, r6, #8 + eor r4,r4, r1 @ Get it so that r4,r5 have 00's where the bytes match the target + eor r5,r5, r1 + uadd8 r4, r4, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 + sel r4, r3, r7 @ bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION uadd8 r5, r5, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 - sel r5, r3, r7 @ bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION - uadd8 r6, r6, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 - sel r6, r5, r7 @ chained....bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION - cbnz r6, 60f + sel r5, r4, r7 @ chained....bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION + cbnz r5, 60f bne 15b @ (Flags from the subs above) If not run out of bytes then go around again pop {r4,r5,r6,r7} @@ -129,22 +129,22 @@ ENTRY(memchr) 60: @ We're here because the fast path found a hit - now we have to track down exactly which word it was @ r0 points to the start of the double word after the one that was tested - @ r5 has the 00/ff pattern for the first word, r6 has the chained value + @ r4 has the 00/ff pattern for the first word, r5 has the chained value cfi_restore_state - cmp r5, #0 + cmp r4, #0 itte eq - moveq r5, r6 @ the end is in the 2nd word + moveq r4, r5 @ the end is in the 2nd word subeq r0,r0,#3 @ Points to 2nd byte of 2nd word subne r0,r0,#7 @ or 2nd byte of 1st word @ r0 currently points to the 2nd byte of the word containing the hit - tst r5, # CHARTSTMASK(0) @ 1st character + tst r4, # CHARTSTMASK(0) @ 1st character bne 61f adds r0,r0,#1 - tst r5, # CHARTSTMASK(1) @ 2nd character + tst r4, # CHARTSTMASK(1) @ 2nd character ittt eq addeq r0,r0,#1 - tsteq r5, # (3<<15) @ 2nd & 3rd character + tsteq r4, # (3<<15) @ 2nd & 3rd character @ If not the 3rd must be the last one addeq r0,r0,#1