From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by sourceware.org (Postfix) with ESMTPS id 5D6083857821 for ; Mon, 19 Apr 2021 23:39:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 5D6083857821 Received: by mail-pj1-x1033.google.com with SMTP id cu16so16824427pjb.4 for ; Mon, 19 Apr 2021 16:39:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lFXa8acIpbaAIqu2TwuauvnqE6lRcAPTyxOsC6uJwiE=; b=c19yi7rEGyKOFJNbu2iHFgIar8128A+5h324caysGo49iz02Ki8pUy5mGE7T3b2lWd 5656CPh0so/MAAQvptXJS5xJ5FUx4o/wGs7T+UEiGWZLpj5nbD7fr3+LyrnAHVDm3tkq FVRXudBpJWhfu88UN42uTI57Wn5R4vcAGGgoijugggUt/bJ2F2bPbGo3zQypOzEda2UC M2Xv2UavuLgWQD/9Ni0cuXV4KnRFEhPWDCRDFV5ffHXiGErk+JCpPkU89oF6zz2o1dQO DHMGdB2+0pTNljbHylSskWFAnWDLRxKqEAhBgsAJJWd0hshULg3goi379/F7rN7qUG3s UpVg== X-Gm-Message-State: AOAM533YHzFJ+c0vQl9BjDWP2Zc7LKaeVMfrLea59XrDOwVb9Bfew832 M4kfhMfVMAt1VSFy4G/IXJPVB5ndQsSFHxi1peI= X-Google-Smtp-Source: ABdhPJxuZsr3gBBYII5ihYQ0nY25up3WOKc3h18sbifyY27vs/5XiIDppEc03GOhe7dVtvkzK8F08EuFXL7Q35oFjXU= X-Received: by 2002:a17:90a:8b97:: with SMTP id z23mr1566221pjn.131.1618875545329; Mon, 19 Apr 2021 16:39:05 -0700 (PDT) MIME-Version: 1.0 References: <20210419184345.2576413-1-goldstein.w.n@gmail.com> In-Reply-To: From: Noah Goldstein Date: Mon, 19 Apr 2021 19:38:54 -0400 Message-ID: Subject: Re: [PATCH v4 1/2] x86: Optimize strlen-evex.S To: "H.J. Lu" Cc: GNU C Library , "Carlos O'Donell" Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-10.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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-List-Received-Date: Mon, 19 Apr 2021 23:39:09 -0000 On Mon, Apr 19, 2021 at 6:16 PM H.J. Lu wrote: > > On Mon, Apr 19, 2021 at 02:43:44PM -0400, Noah Goldstein wrote: > > No bug. This commit optimizes strlen-evex.S. The > > optimizations are mostly small things but they add up to roughly > > 10-30% performance improvement for strlen. The results for strnlen are > > bit more ambiguous. test-strlen, test-strnlen, test-wcslen, and > > test-wcsnlen are all passing. > > > > Signed-off-by: Noah Goldstein > > --- > > sysdeps/x86_64/multiarch/strlen-evex.S | 584 ++++++++++++++----------- > > 1 file changed, 320 insertions(+), 264 deletions(-) > > > > diff --git a/sysdeps/x86_64/multiarch/strlen-evex.S b/sysdeps/x86_64/multiarch/strlen-evex.S > > index 0583819078..36b28198c8 100644 > > --- a/sysdeps/x86_64/multiarch/strlen-evex.S > > +++ b/sysdeps/x86_64/multiarch/strlen-evex.S > > @@ -29,11 +29,13 @@ > > # ifdef USE_AS_WCSLEN > > # define VPCMP vpcmpd > > # define VPMINU vpminud > > -# define SHIFT_REG r9d > > +# define SHIFT_REG ecx > > +# define CHAR_SIZE 4 > > # else > > # define VPCMP vpcmpb > > # define VPMINU vpminub > > -# define SHIFT_REG ecx > > +# define SHIFT_REG edx > > +# define CHAR_SIZE 1 > > # endif > > > > # define XMMZERO xmm16 > > @@ -46,132 +48,168 @@ > > # define YMM6 ymm22 > > > > # define VEC_SIZE 32 > > +# define PAGE_SIZE 4096 > > +# define LOG_PAGE_SIZE 12 > > +# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE) > > > > .section .text.evex,"ax",@progbits > > ENTRY (STRLEN) > > # ifdef USE_AS_STRNLEN > > - /* Check for zero length. */ > > + /* Check zero length. */ > > test %RSI_LP, %RSI_LP > > jz L(zero) > > -# ifdef USE_AS_WCSLEN > > - shl $2, %RSI_LP > > -# elif defined __ILP32__ > > +# ifdef __ILP32__ > > /* Clear the upper 32 bits. */ > > movl %esi, %esi > > # endif > > mov %RSI_LP, %R8_LP > > # endif > > - movl %edi, %ecx > > - movq %rdi, %rdx > > + movl %edi, %eax > > vpxorq %XMMZERO, %XMMZERO, %XMMZERO > > - > > + /* Shift left eax to clear all bits not relevant to page cross > > + check. This saves 2 bytes of code as opposed to using andl with > > + PAGE_SIZE - 1. Then compare with PAGE_SIZE - VEC_SIZE shifted > > + left by the same amount (an imm32 either way). */ > > + sall $(32 - LOG_PAGE_SIZE), %eax > > I prefer AND over SAL for better throughput. Done. > > > H.J. > --- > > /* Check if we may cross page boundary with one vector load. */ > > - andl $(2 * VEC_SIZE - 1), %ecx > > - cmpl $VEC_SIZE, %ecx > > - ja L(cros_page_boundary) > > + cmpl $((PAGE_SIZE - VEC_SIZE) << (32 - LOG_PAGE_SIZE)), %eax > > + ja L(cross_page_boundary) > > > > /* Check the first VEC_SIZE bytes. Each bit in K0 represents a > > null byte. */ > > VPCMP $0, (%rdi), %YMMZERO, %k0 > > kmovd %k0, %eax > > - testl %eax, %eax > > - > > # ifdef USE_AS_STRNLEN > > - jnz L(first_vec_x0_check) > > - /* Adjust length and check the end of data. */ > > - subq $VEC_SIZE, %rsi > > - jbe L(max) > > -# else > > - jnz L(first_vec_x0) > > + /* If length < CHAR_PER_VEC handle special. */ > > + cmpq $CHAR_PER_VEC, %rsi > > + jbe L(first_vec_x0) > > # endif > > - > > - /* Align data for aligned loads in the loop. */ > > - addq $VEC_SIZE, %rdi > > - andl $(VEC_SIZE - 1), %ecx > > - andq $-VEC_SIZE, %rdi > > - > > + testl %eax, %eax > > + jz L(aligned_more) > > + tzcntl %eax, %eax > > + ret > > # ifdef USE_AS_STRNLEN > > - /* Adjust length. */ > > - addq %rcx, %rsi > > +L(zero): > > + xorl %eax, %eax > > + ret > > > > - subq $(VEC_SIZE * 4), %rsi > > - jbe L(last_4x_vec_or_less) > > + .p2align 4 > > +L(first_vec_x0): > > + /* Set bit for max len so that tzcnt will return min of max len > > + and position of first match. */ > > + btsq %rsi, %rax > > + tzcntl %eax, %eax > > + ret > > # endif > > - jmp L(more_4x_vec) > > > > .p2align 4 > > -L(cros_page_boundary): > > - andl $(VEC_SIZE - 1), %ecx > > - andq $-VEC_SIZE, %rdi > > - > > -# ifdef USE_AS_WCSLEN > > - /* NB: Divide shift count by 4 since each bit in K0 represent 4 > > - bytes. */ > > - movl %ecx, %SHIFT_REG > > - sarl $2, %SHIFT_REG > > +L(first_vec_x1): > > + tzcntl %eax, %eax > > + /* Safe to use 32 bit instructions as these are only called for > > + size = [1, 159]. */ > > +# ifdef USE_AS_STRNLEN > > + /* Use ecx which was computed earlier to compute correct value. > > + */ > > + leal -(CHAR_PER_VEC * 4 + 1)(%rcx, %rax), %eax > > +# else > > + subl %edx, %edi > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarl $2, %edi > > +# endif > > + leal CHAR_PER_VEC(%rdi, %rax), %eax > > # endif > > - VPCMP $0, (%rdi), %YMMZERO, %k0 > > - kmovd %k0, %eax > > + ret > > > > - /* Remove the leading bytes. */ > > - sarxl %SHIFT_REG, %eax, %eax > > - testl %eax, %eax > > - jz L(aligned_more) > > + .p2align 4 > > +L(first_vec_x2): > > tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > + /* Safe to use 32 bit instructions as these are only called for > > + size = [1, 159]. */ > > # ifdef USE_AS_STRNLEN > > - /* Check the end of data. */ > > - cmpq %rax, %rsi > > - jbe L(max) > > -# endif > > - addq %rdi, %rax > > - addq %rcx, %rax > > - subq %rdx, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* Use ecx which was computed earlier to compute correct value. > > + */ > > + leal -(CHAR_PER_VEC * 3 + 1)(%rcx, %rax), %eax > > +# else > > + subl %edx, %edi > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarl $2, %edi > > +# endif > > + leal (CHAR_PER_VEC * 2)(%rdi, %rax), %eax > > # endif > > ret > > > > .p2align 4 > > -L(aligned_more): > > +L(first_vec_x3): > > + tzcntl %eax, %eax > > + /* Safe to use 32 bit instructions as these are only called for > > + size = [1, 159]. */ > > # ifdef USE_AS_STRNLEN > > - /* "rcx" is less than VEC_SIZE. Calculate "rdx + rcx - VEC_SIZE" > > - with "rdx - (VEC_SIZE - rcx)" instead of "(rdx + rcx) - VEC_SIZE" > > - to void possible addition overflow. */ > > - negq %rcx > > - addq $VEC_SIZE, %rcx > > - > > - /* Check the end of data. */ > > - subq %rcx, %rsi > > - jbe L(max) > > + /* Use ecx which was computed earlier to compute correct value. > > + */ > > + leal -(CHAR_PER_VEC * 2 + 1)(%rcx, %rax), %eax > > +# else > > + subl %edx, %edi > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarl $2, %edi > > +# endif > > + leal (CHAR_PER_VEC * 3)(%rdi, %rax), %eax > > # endif > > + ret > > > > - addq $VEC_SIZE, %rdi > > - > > + .p2align 4 > > +L(first_vec_x4): > > + tzcntl %eax, %eax > > + /* Safe to use 32 bit instructions as these are only called for > > + size = [1, 159]. */ > > # ifdef USE_AS_STRNLEN > > - subq $(VEC_SIZE * 4), %rsi > > - jbe L(last_4x_vec_or_less) > > + /* Use ecx which was computed earlier to compute correct value. > > + */ > > + leal -(CHAR_PER_VEC + 1)(%rcx, %rax), %eax > > +# else > > + subl %edx, %edi > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarl $2, %edi > > +# endif > > + leal (CHAR_PER_VEC * 4)(%rdi, %rax), %eax > > # endif > > + ret > > > > -L(more_4x_vec): > > + .p2align 5 > > +L(aligned_more): > > + movq %rdi, %rdx > > + /* Align data to VEC_SIZE. */ > > + andq $-(VEC_SIZE), %rdi > > +L(cross_page_continue): > > /* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time > > since data is only aligned to VEC_SIZE. */ > > - VPCMP $0, (%rdi), %YMMZERO, %k0 > > - kmovd %k0, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x0) > > - > > +# ifdef USE_AS_STRNLEN > > + /* + CHAR_SIZE because it simplies the logic in > > + last_4x_vec_or_less. */ > > + leaq (VEC_SIZE * 5 + CHAR_SIZE)(%rdi), %rcx > > + subq %rdx, %rcx > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarl $2, %ecx > > +# endif > > +# endif > > + /* Load first VEC regardless. */ > > VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0 > > +# ifdef USE_AS_STRNLEN > > + /* Adjust length. If near end handle specially. */ > > + subq %rcx, %rsi > > + jb L(last_4x_vec_or_less) > > +# endif > > kmovd %k0, %eax > > testl %eax, %eax > > jnz L(first_vec_x1) > > > > VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0 > > kmovd %k0, %eax > > - testl %eax, %eax > > + test %eax, %eax > > jnz L(first_vec_x2) > > > > VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0 > > @@ -179,258 +217,276 @@ L(more_4x_vec): > > testl %eax, %eax > > jnz L(first_vec_x3) > > > > - addq $(VEC_SIZE * 4), %rdi > > - > > -# ifdef USE_AS_STRNLEN > > - subq $(VEC_SIZE * 4), %rsi > > - jbe L(last_4x_vec_or_less) > > -# endif > > - > > - /* Align data to 4 * VEC_SIZE. */ > > - movq %rdi, %rcx > > - andl $(4 * VEC_SIZE - 1), %ecx > > - andq $-(4 * VEC_SIZE), %rdi > > + VPCMP $0, (VEC_SIZE * 4)(%rdi), %YMMZERO, %k0 > > + kmovd %k0, %eax > > + testl %eax, %eax > > + jnz L(first_vec_x4) > > > > + addq $VEC_SIZE, %rdi > > # ifdef USE_AS_STRNLEN > > - /* Adjust length. */ > > + /* Check if at last VEC_SIZE * 4 length. */ > > + cmpq $(CHAR_PER_VEC * 4 - 1), %rsi > > + jbe L(last_4x_vec_or_less_load) > > + movl %edi, %ecx > > + andl $(VEC_SIZE * 4 - 1), %ecx > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarl $2, %ecx > > +# endif > > + /* Readjust length. */ > > addq %rcx, %rsi > > # endif > > + /* Align data to VEC_SIZE * 4. */ > > + andq $-(VEC_SIZE * 4), %rdi > > > > + /* Compare 4 * VEC at a time forward. */ > > .p2align 4 > > L(loop_4x_vec): > > - /* Compare 4 * VEC at a time forward. */ > > - VMOVA (%rdi), %YMM1 > > - VMOVA VEC_SIZE(%rdi), %YMM2 > > - VMOVA (VEC_SIZE * 2)(%rdi), %YMM3 > > - VMOVA (VEC_SIZE * 3)(%rdi), %YMM4 > > - > > - VPMINU %YMM1, %YMM2, %YMM5 > > - VPMINU %YMM3, %YMM4, %YMM6 > > + /* Load first VEC regardless. */ > > + VMOVA (VEC_SIZE * 4)(%rdi), %YMM1 > > +# ifdef USE_AS_STRNLEN > > + /* Break if at end of length. */ > > + subq $(CHAR_PER_VEC * 4), %rsi > > + jb L(last_4x_vec_or_less_cmpeq) > > +# endif > > + /* Save some code size by microfusing VPMINU with the load. Since > > + the matches in ymm2/ymm4 can only be returned if there where no > > + matches in ymm1/ymm3 respectively there is no issue with overlap. > > + */ > > + VPMINU (VEC_SIZE * 5)(%rdi), %YMM1, %YMM2 > > + VMOVA (VEC_SIZE * 6)(%rdi), %YMM3 > > + VPMINU (VEC_SIZE * 7)(%rdi), %YMM3, %YMM4 > > + > > + VPCMP $0, %YMM2, %YMMZERO, %k0 > > + VPCMP $0, %YMM4, %YMMZERO, %k1 > > + subq $-(VEC_SIZE * 4), %rdi > > + kortestd %k0, %k1 > > + jz L(loop_4x_vec) > > + > > + /* Check if end was in first half. */ > > + kmovd %k0, %eax > > + subq %rdx, %rdi > > +# ifdef USE_AS_WCSLEN > > + shrq $2, %rdi > > +# endif > > + testl %eax, %eax > > + jz L(second_vec_return) > > > > - VPMINU %YMM5, %YMM6, %YMM5 > > - VPCMP $0, %YMM5, %YMMZERO, %k0 > > - ktestd %k0, %k0 > > - jnz L(4x_vec_end) > > + VPCMP $0, %YMM1, %YMMZERO, %k2 > > + kmovd %k2, %edx > > + /* Combine VEC1 matches (edx) with VEC2 matches (eax). */ > > +# ifdef USE_AS_WCSLEN > > + sall $CHAR_PER_VEC, %eax > > + orl %edx, %eax > > + tzcntl %eax, %eax > > +# else > > + salq $CHAR_PER_VEC, %rax > > + orq %rdx, %rax > > + tzcntq %rax, %rax > > +# endif > > + addq %rdi, %rax > > + ret > > > > - addq $(VEC_SIZE * 4), %rdi > > > > -# ifndef USE_AS_STRNLEN > > - jmp L(loop_4x_vec) > > -# else > > - subq $(VEC_SIZE * 4), %rsi > > - ja L(loop_4x_vec) > > +# ifdef USE_AS_STRNLEN > > > > +L(last_4x_vec_or_less_load): > > + /* Depending on entry adjust rdi / prepare first VEC in YMM1. */ > > + VMOVA (VEC_SIZE * 4)(%rdi), %YMM1 > > +L(last_4x_vec_or_less_cmpeq): > > + VPCMP $0, %YMM1, %YMMZERO, %k0 > > + addq $(VEC_SIZE * 3), %rdi > > L(last_4x_vec_or_less): > > - /* Less than 4 * VEC and aligned to VEC_SIZE. */ > > - addl $(VEC_SIZE * 2), %esi > > - jle L(last_2x_vec) > > - > > - VPCMP $0, (%rdi), %YMMZERO, %k0 > > kmovd %k0, %eax > > + /* If remaining length > VEC_SIZE * 2. This works if esi is off by > > + VEC_SIZE * 4. */ > > + testl $(CHAR_PER_VEC * 2), %esi > > + jnz L(last_4x_vec) > > + > > + /* length may have been negative or positive by an offset of > > + CHAR_PER_VEC * 4 depending on where this was called from. This > > + fixes that. */ > > + andl $(CHAR_PER_VEC * 4 - 1), %esi > > testl %eax, %eax > > - jnz L(first_vec_x0) > > + jnz L(last_vec_x1_check) > > > > - VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0 > > - kmovd %k0, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x1) > > + /* Check the end of data. */ > > + subl $CHAR_PER_VEC, %esi > > + jb L(max) > > > > VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0 > > kmovd %k0, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x2_check) > > - subl $VEC_SIZE, %esi > > - jle L(max) > > + tzcntl %eax, %eax > > + /* Check the end of data. */ > > + cmpl %eax, %esi > > + jb L(max) > > > > - VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0 > > - kmovd %k0, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x3_check) > > + subq %rdx, %rdi > > +# ifdef USE_AS_WCSLEN > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarq $2, %rdi > > +# endif > > + leaq (CHAR_PER_VEC * 2)(%rdi, %rax), %rax > > + ret > > +L(max): > > movq %r8, %rax > > + ret > > +# endif > > + > > + /* Placed here in strnlen so that the jcc L(last_4x_vec_or_less) > > + in the 4x VEC loop can use 2 byte encoding. */ > > + .p2align 4 > > +L(second_vec_return): > > + VPCMP $0, %YMM3, %YMMZERO, %k0 > > + /* Combine YMM3 matches (k0) with YMM4 matches (k1). */ > > +# ifdef USE_AS_WCSLEN > > + kunpckbw %k0, %k1, %k0 > > + kmovd %k0, %eax > > + tzcntl %eax, %eax > > +# else > > + kunpckdq %k0, %k1, %k0 > > + kmovq %k0, %rax > > + tzcntq %rax, %rax > > +# endif > > + leaq (CHAR_PER_VEC * 2)(%rdi, %rax), %rax > > + ret > > + > > + > > +# ifdef USE_AS_STRNLEN > > +L(last_vec_x1_check): > > + tzcntl %eax, %eax > > + /* Check the end of data. */ > > + cmpl %eax, %esi > > + jb L(max) > > + subq %rdx, %rdi > > # ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarq $2, %rdi > > # endif > > + leaq (CHAR_PER_VEC)(%rdi, %rax), %rax > > ret > > > > .p2align 4 > > -L(last_2x_vec): > > - addl $(VEC_SIZE * 2), %esi > > +L(last_4x_vec): > > + /* Test first 2x VEC normally. */ > > + testl %eax, %eax > > + jnz L(last_vec_x1) > > > > - VPCMP $0, (%rdi), %YMMZERO, %k0 > > + VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0 > > kmovd %k0, %eax > > testl %eax, %eax > > - jnz L(first_vec_x0_check) > > - subl $VEC_SIZE, %esi > > - jle L(max) > > + jnz L(last_vec_x2) > > > > - VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0 > > + /* Normalize length. */ > > + andl $(CHAR_PER_VEC * 4 - 1), %esi > > + VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0 > > kmovd %k0, %eax > > testl %eax, %eax > > - jnz L(first_vec_x1_check) > > - movq %r8, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > -# endif > > - ret > > + jnz L(last_vec_x3) > > > > - .p2align 4 > > -L(first_vec_x0_check): > > + /* Check the end of data. */ > > + subl $(CHAR_PER_VEC * 3), %esi > > + jb L(max) > > + > > + VPCMP $0, (VEC_SIZE * 4)(%rdi), %YMMZERO, %k0 > > + kmovd %k0, %eax > > tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > /* Check the end of data. */ > > - cmpq %rax, %rsi > > - jbe L(max) > > - addq %rdi, %rax > > - subq %rdx, %rax > > + cmpl %eax, %esi > > + jb L(max_end) > > + > > + subq %rdx, %rdi > > # ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarq $2, %rdi > > # endif > > + leaq (CHAR_PER_VEC * 4)(%rdi, %rax), %rax > > ret > > > > .p2align 4 > > -L(first_vec_x1_check): > > +L(last_vec_x1): > > tzcntl %eax, %eax > > + subq %rdx, %rdi > > # ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > - /* Check the end of data. */ > > - cmpq %rax, %rsi > > - jbe L(max) > > - addq $VEC_SIZE, %rax > > - addq %rdi, %rax > > - subq %rdx, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarq $2, %rdi > > # endif > > + leaq (CHAR_PER_VEC)(%rdi, %rax), %rax > > ret > > > > .p2align 4 > > -L(first_vec_x2_check): > > +L(last_vec_x2): > > tzcntl %eax, %eax > > + subq %rdx, %rdi > > # ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > - /* Check the end of data. */ > > - cmpq %rax, %rsi > > - jbe L(max) > > - addq $(VEC_SIZE * 2), %rax > > - addq %rdi, %rax > > - subq %rdx, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarq $2, %rdi > > # endif > > + leaq (CHAR_PER_VEC * 2)(%rdi, %rax), %rax > > ret > > > > .p2align 4 > > -L(first_vec_x3_check): > > +L(last_vec_x3): > > tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > + subl $(CHAR_PER_VEC * 2), %esi > > /* Check the end of data. */ > > - cmpq %rax, %rsi > > - jbe L(max) > > - addq $(VEC_SIZE * 3), %rax > > - addq %rdi, %rax > > - subq %rdx, %rax > > + cmpl %eax, %esi > > + jb L(max_end) > > + subq %rdx, %rdi > > # ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* NB: Divide bytes by 4 to get the wchar_t count. */ > > + sarq $2, %rdi > > # endif > > + leaq (CHAR_PER_VEC * 3)(%rdi, %rax), %rax > > ret > > - > > - .p2align 4 > > -L(max): > > +L(max_end): > > movq %r8, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > -# endif > > - ret > > - > > - .p2align 4 > > -L(zero): > > - xorl %eax, %eax > > ret > > # endif > > > > + /* Cold case for crossing page with first load. */ > > .p2align 4 > > -L(first_vec_x0): > > - tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > - addq %rdi, %rax > > - subq %rdx, %rax > > +L(cross_page_boundary): > > + movq %rdi, %rdx > > + /* Align data to VEC_SIZE. */ > > + andq $-VEC_SIZE, %rdi > > + VPCMP $0, (%rdi), %YMMZERO, %k0 > > + kmovd %k0, %eax > > + /* Remove the leading bytes. */ > > # ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > + /* NB: Divide shift count by 4 since each bit in K0 represent 4 > > + bytes. */ > > + movl %edx, %ecx > > + shrl $2, %ecx > > + andl $(CHAR_PER_VEC - 1), %ecx > > # endif > > - ret > > - > > - .p2align 4 > > -L(first_vec_x1): > > + /* SHIFT_REG is ecx for USE_AS_WCSLEN and edx otherwise. */ > > + sarxl %SHIFT_REG, %eax, %eax > > + testl %eax, %eax > > +# ifndef USE_AS_STRNLEN > > + jz L(cross_page_continue) > > tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > - addq $VEC_SIZE, %rax > > - addq %rdi, %rax > > - subq %rdx, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > -# endif > > ret > > - > > - .p2align 4 > > -L(first_vec_x2): > > - tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > - addq $(VEC_SIZE * 2), %rax > > - addq %rdi, %rax > > - subq %rdx, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > -# endif > > +# else > > + jnz L(cross_page_less_vec) > > +# ifndef USE_AS_WCSLEN > > + movl %edx, %ecx > > + andl $(CHAR_PER_VEC - 1), %ecx > > +# endif > > + movl $CHAR_PER_VEC, %eax > > + subl %ecx, %eax > > + /* Check the end of data. */ > > + cmpq %rax, %rsi > > + ja L(cross_page_continue) > > + movl %esi, %eax > > ret > > - > > - .p2align 4 > > -L(4x_vec_end): > > - VPCMP $0, %YMM1, %YMMZERO, %k0 > > - kmovd %k0, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x0) > > - VPCMP $0, %YMM2, %YMMZERO, %k1 > > - kmovd %k1, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x1) > > - VPCMP $0, %YMM3, %YMMZERO, %k2 > > - kmovd %k2, %eax > > - testl %eax, %eax > > - jnz L(first_vec_x2) > > - VPCMP $0, %YMM4, %YMMZERO, %k3 > > - kmovd %k3, %eax > > -L(first_vec_x3): > > +L(cross_page_less_vec): > > tzcntl %eax, %eax > > -# ifdef USE_AS_WCSLEN > > - /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ > > - sall $2, %eax > > -# endif > > - addq $(VEC_SIZE * 3), %rax > > - addq %rdi, %rax > > - subq %rdx, %rax > > -# ifdef USE_AS_WCSLEN > > - shrq $2, %rax > > -# endif > > + /* Select min of length and position of first null. */ > > + cmpq %rax, %rsi > > + cmovb %esi, %eax > > ret > > +# endif > > > > END (STRLEN) > > #endif > > -- > > 2.29.2 > >