From patchwork Tue Feb 28 17:24:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella X-Patchwork-Id: 65797 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 949133854803 for ; Tue, 28 Feb 2023 17:25:18 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 949133854803 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1677605118; bh=WXZOhxTFWhQSgWtKDhx5dCv6e9ksp6+UC9iLiERlHPw=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=Hrv7DekzUjOXNm7L9bt9uynIL5RJuvdPgUOac4YVJKaCPd3/VL/aUNO1vJbWFjgJZ Vkfvhl9kL5NKEQ9CZ166AbHkvp1ZJdHDtlSgwJo5SHklqnaFRZVo+dxw+MRBtQN5e9 jbWuBpYQNwfd7m5YU9GssLccxwurb78KZZ1CSPJo= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-oa1-x2d.google.com (mail-oa1-x2d.google.com [IPv6:2001:4860:4864:20::2d]) by sourceware.org (Postfix) with ESMTPS id 9D1EE3858C5E for ; Tue, 28 Feb 2023 17:24:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9D1EE3858C5E Received: by mail-oa1-x2d.google.com with SMTP id 586e51a60fabf-1720433ba75so11644723fac.5 for ; Tue, 28 Feb 2023 09:24:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677605050; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WXZOhxTFWhQSgWtKDhx5dCv6e9ksp6+UC9iLiERlHPw=; b=1d6NpCMjBcZE9pqwgKC2Cfak2rf1gpVeTiCv6kITlBwajXbVpCPMOy+XBfpiJyo31W cCo/j8dJZwnVJnowvGCWl1+2L+sOXkN0D3Pekg6g9lk6xC/fwU83DFUQSPLjhJ/mtrRS S/nemMX89InDReZtTudLiisWQpR9QEnudwfwgyExq6KINjLj+ZAID7TKvfh0tlYXFSoA pVJXh5MOjKMj69yvfTbNWIwoiNLKPKfV0QvTPUtwtHpEbb0Fzp3MN4sEXjEYTZFVijPf KVKapRHOwhMTXnNVaG84synauZhTPvR7RBXNDyuJ0kobrZOu0Krhp1Yll+AzpM0qLqrG xM+A== X-Gm-Message-State: AO0yUKWS78K0s9k4hNJ2oW8y9ZQTJ1yuSNhWhIw5hotcH0qzwpaFQgV3 +r4mGc/ijDuwn8xm0bsDEXQOvhTUfzwgDP9deDc= X-Google-Smtp-Source: AK7set9JoAjdSCNxJXA2+dmlQflfORqkdHxVfxW8C9nTAEVbmhp5fCDe+VvjrZdEVOuCTScCmFFUeg== X-Received: by 2002:a05:6870:c386:b0:16e:93ba:e55e with SMTP id g6-20020a056870c38600b0016e93bae55emr1721766oao.8.1677605050224; Tue, 28 Feb 2023 09:24:10 -0800 (PST) Received: from mandiga.. ([2804:1b3:a7c3:d849:7299:419:6fb3:7a8]) by smtp.gmail.com with ESMTPSA id e7-20020a05683013c700b00684152e9ff2sm3925220otq.0.2023.02.28.09.24.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Feb 2023 09:24:09 -0800 (PST) To: libc-alpha@sourceware.org, Richard Henderson Subject: [PATCH 3/3] alpha: Remove strncmp optimization Date: Tue, 28 Feb 2023 14:24:00 -0300 Message-Id: <20230228172400.2763397-4-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230228172400.2763397-1-adhemerval.zanella@linaro.org> References: <20230228172400.2763397-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-11.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SCC_10_SHORT_WORD_LINES, SCC_5_SHORT_WORD_LINES, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Reply-To: Adhemerval Zanella Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" The generic implementation already cover word access along with cmpbge for both aligned and unaligned, so use it instead. Checked qemu static for alpha-linux-gnu. --- sysdeps/alpha/strncmp.S | 276 ---------------------------------------- 1 file changed, 276 deletions(-) delete mode 100644 sysdeps/alpha/strncmp.S diff --git a/sysdeps/alpha/strncmp.S b/sysdeps/alpha/strncmp.S deleted file mode 100644 index a54cc45a0a..0000000000 --- a/sysdeps/alpha/strncmp.S +++ /dev/null @@ -1,276 +0,0 @@ -/* Copyright (C) 1996-2023 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library. If not, see - . */ - -/* Bytewise compare two null-terminated strings of length no longer than N. */ - -#include - - .set noat - .set noreorder - -/* EV6 only predicts one branch per octaword. We'll use these to push - subsequent branches back to the next bundle. This will generally add - a fetch+decode cycle to older machines, so skip in that case. */ -#ifdef __alpha_fix__ -# define ev6_unop unop -#else -# define ev6_unop -#endif - - .text - -ENTRY(strncmp) -#ifdef PROF - ldgp gp, 0(pv) - lda AT, _mcount - jsr AT, (AT), _mcount - .prologue 1 -#else - .prologue 0 -#endif - - xor a0, a1, t2 # are s1 and s2 co-aligned? - beq a2, $zerolength - ldq_u t0, 0(a0) # load asap to give cache time to catch up - ldq_u t1, 0(a1) - lda t3, -1 - and t2, 7, t2 - srl t3, 1, t6 - and a0, 7, t4 # find s1 misalignment - and a1, 7, t5 # find s2 misalignment - cmovlt a2, t6, a2 # bound neg count to LONG_MAX - addq a1, a2, a3 # s2+count - addq a2, t4, a2 # bias count by s1 misalignment - and a2, 7, t10 # ofs of last byte in s1 last word - srl a2, 3, a2 # remaining full words in s1 count - bne t2, $unaligned - - /* On entry to this basic block: - t0 == the first word of s1. - t1 == the first word of s2. - t3 == -1. */ -$aligned: - mskqh t3, a1, t8 # mask off leading garbage - ornot t1, t8, t1 - ornot t0, t8, t0 - cmpbge zero, t1, t7 # bits set iff null found - beq a2, $eoc # check end of count - bne t7, $eos - beq t10, $ant_loop - - /* Aligned compare main loop. - On entry to this basic block: - t0 == an s1 word. - t1 == an s2 word not containing a null. */ - - .align 4 -$a_loop: - xor t0, t1, t2 # e0 : - bne t2, $wordcmp # .. e1 (zdb) - ldq_u t1, 8(a1) # e0 : - ldq_u t0, 8(a0) # .. e1 : - - subq a2, 1, a2 # e0 : - addq a1, 8, a1 # .. e1 : - addq a0, 8, a0 # e0 : - beq a2, $eoc # .. e1 : - - cmpbge zero, t1, t7 # e0 : - beq t7, $a_loop # .. e1 : - - br $eos - - /* Alternate aligned compare loop, for when there's no trailing - bytes on the count. We have to avoid reading too much data. */ - .align 4 -$ant_loop: - xor t0, t1, t2 # e0 : - ev6_unop - ev6_unop - bne t2, $wordcmp # .. e1 (zdb) - - subq a2, 1, a2 # e0 : - beq a2, $zerolength # .. e1 : - ldq_u t1, 8(a1) # e0 : - ldq_u t0, 8(a0) # .. e1 : - - addq a1, 8, a1 # e0 : - addq a0, 8, a0 # .. e1 : - cmpbge zero, t1, t7 # e0 : - beq t7, $ant_loop # .. e1 : - - br $eos - - /* The two strings are not co-aligned. Align s1 and cope. */ - /* On entry to this basic block: - t0 == the first word of s1. - t1 == the first word of s2. - t3 == -1. - t4 == misalignment of s1. - t5 == misalignment of s2. - t10 == misalignment of s1 end. */ - .align 4 -$unaligned: - /* If s1 misalignment is larger than s2 misalignment, we need - extra startup checks to avoid SEGV. */ - subq a1, t4, a1 # adjust s2 for s1 misalignment - cmpult t4, t5, t9 - subq a3, 1, a3 # last byte of s2 - bic a1, 7, t8 - mskqh t3, t5, t7 # mask garbage in s2 - subq a3, t8, a3 - ornot t1, t7, t7 - srl a3, 3, a3 # remaining full words in s2 count - beq t9, $u_head - - /* Failing that, we need to look for both eos and eoc within the - first word of s2. If we find either, we can continue by - pretending that the next word of s2 is all zeros. */ - lda t2, 0 # next = zero - cmpeq a3, 0, t8 # eoc in the first word of s2? - cmpbge zero, t7, t7 # eos in the first word of s2? - or t7, t8, t8 - bne t8, $u_head_nl - - /* We know just enough now to be able to assemble the first - full word of s2. We can still find a zero at the end of it. - - On entry to this basic block: - t0 == first word of s1 - t1 == first partial word of s2. - t3 == -1. - t10 == ofs of last byte in s1 last word. - t11 == ofs of last byte in s2 last word. */ -$u_head: - ldq_u t2, 8(a1) # load second partial s2 word - subq a3, 1, a3 -$u_head_nl: - extql t1, a1, t1 # create first s2 word - mskqh t3, a0, t8 - extqh t2, a1, t4 - ornot t0, t8, t0 # kill s1 garbage - or t1, t4, t1 # s2 word now complete - cmpbge zero, t0, t7 # find eos in first s1 word - ornot t1, t8, t1 # kill s2 garbage - beq a2, $eoc - subq a2, 1, a2 - bne t7, $eos - mskql t3, a1, t8 # mask out s2[1] bits we have seen - xor t0, t1, t4 # compare aligned words - or t2, t8, t8 - bne t4, $wordcmp - cmpbge zero, t8, t7 # eos in high bits of s2[1]? - cmpeq a3, 0, t8 # eoc in s2[1]? - or t7, t8, t7 - bne t7, $u_final - - /* Unaligned copy main loop. In order to avoid reading too much, - the loop is structured to detect zeros in aligned words from s2. - This has, unfortunately, effectively pulled half of a loop - iteration out into the head and half into the tail, but it does - prevent nastiness from accumulating in the very thing we want - to run as fast as possible. - - On entry to this basic block: - t2 == the unshifted low-bits from the next s2 word. - t10 == ofs of last byte in s1 last word. - t11 == ofs of last byte in s2 last word. */ - .align 4 -$u_loop: - extql t2, a1, t3 # e0 : - ldq_u t2, 16(a1) # .. e1 : load next s2 high bits - ldq_u t0, 8(a0) # e0 : load next s1 word - addq a1, 8, a1 # .. e1 : - - addq a0, 8, a0 # e0 : - subq a3, 1, a3 # .. e1 : - extqh t2, a1, t1 # e0 : - cmpbge zero, t0, t7 # .. e1 : eos in current s1 word - - or t1, t3, t1 # e0 : - beq a2, $eoc # .. e1 : eoc in current s1 word - subq a2, 1, a2 # e0 : - cmpbge zero, t2, t4 # .. e1 : eos in s2[1] - - xor t0, t1, t3 # e0 : compare the words - ev6_unop - ev6_unop - bne t7, $eos # .. e1 : - - cmpeq a3, 0, t5 # e0 : eoc in s2[1] - ev6_unop - ev6_unop - bne t3, $wordcmp # .. e1 : - - or t4, t5, t4 # e0 : eos or eoc in s2[1]. - beq t4, $u_loop # .. e1 (zdb) - - /* We've found a zero in the low bits of the last s2 word. Get - the next s1 word and align them. */ - .align 3 -$u_final: - ldq_u t0, 8(a0) - extql t2, a1, t1 - cmpbge zero, t1, t7 - bne a2, $eos - - /* We've hit end of count. Zero everything after the count - and compare whats left. */ - .align 3 -$eoc: - mskql t0, t10, t0 - mskql t1, t10, t1 - cmpbge zero, t1, t7 - - /* We've found a zero somewhere in a word we just read. - On entry to this basic block: - t0 == s1 word - t1 == s2 word - t7 == cmpbge mask containing the zero. */ - .align 3 -$eos: - negq t7, t6 # create bytemask of valid data - and t6, t7, t8 - subq t8, 1, t6 - or t6, t8, t7 - zapnot t0, t7, t0 # kill the garbage - zapnot t1, t7, t1 - xor t0, t1, v0 # ... and compare - beq v0, $done - - /* Here we have two differing co-aligned words in t0 & t1. - Bytewise compare them and return (t0 > t1 ? 1 : -1). */ - .align 3 -$wordcmp: - cmpbge t0, t1, t2 # comparison yields bit mask of ge - cmpbge t1, t0, t3 - xor t2, t3, t0 # bits set iff t0/t1 bytes differ - negq t0, t1 # clear all but least bit - and t0, t1, t0 - lda v0, -1 - and t0, t2, t1 # was bit set in t0 > t1? - cmovne t1, 1, v0 -$done: - ret - - .align 3 -$zerolength: - clr v0 - ret - - END(strncmp) -libc_hidden_builtin_def (strncmp)