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From: Noah Goldstein <nwg@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] x86: Remove strcspn-sse2.S and use the generic implementation Date: Fri, 25 Mar 2022 18:18:21 +0000 (GMT) [thread overview] Message-ID: <20220325181821.A533B389EC5F@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=fe28e7d9d9535ebab4081d195c553b4fbf39d9ae commit fe28e7d9d9535ebab4081d195c553b4fbf39d9ae Author: Noah Goldstein <goldstein.w.n@gmail.com> Date: Wed Mar 23 16:57:26 2022 -0500 x86: Remove strcspn-sse2.S and use the generic implementation The generic implementation is faster. geometric_mean(N=20) of all benchmarks New / Original: .678 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com> Diff: --- .../multiarch/{strcspn-sse2.S => strcspn-sse2.c} | 8 +- sysdeps/x86_64/strcspn.S | 119 --------------------- 2 files changed, 4 insertions(+), 123 deletions(-) diff --git a/sysdeps/x86_64/multiarch/strcspn-sse2.S b/sysdeps/x86_64/multiarch/strcspn-sse2.c similarity index 85% rename from sysdeps/x86_64/multiarch/strcspn-sse2.S rename to sysdeps/x86_64/multiarch/strcspn-sse2.c index f97e856e1f..3a04bb39fc 100644 --- a/sysdeps/x86_64/multiarch/strcspn-sse2.S +++ b/sysdeps/x86_64/multiarch/strcspn-sse2.c @@ -1,4 +1,4 @@ -/* strcspn optimized with SSE2. +/* strcspn. Copyright (C) 2017-2022 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -19,10 +19,10 @@ #if IS_IN (libc) # include <sysdep.h> -# define strcspn __strcspn_sse2 +# define STRCSPN __strcspn_sse2 # undef libc_hidden_builtin_def -# define libc_hidden_builtin_def(strcspn) +# define libc_hidden_builtin_def(STRCSPN) #endif -#include <sysdeps/x86_64/strcspn.S> +#include <string/strcspn.c> diff --git a/sysdeps/x86_64/strcspn.S b/sysdeps/x86_64/strcspn.S deleted file mode 100644 index f3cd86c606..0000000000 --- a/sysdeps/x86_64/strcspn.S +++ /dev/null @@ -1,119 +0,0 @@ -/* strcspn (str, ss) -- Return the length of the initial segment of STR - which contains no characters from SS. - For AMD x86-64. - Copyright (C) 1994-2022 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 - <https://www.gnu.org/licenses/>. */ - -#include <sysdep.h> -#include "asm-syntax.h" - - .text -ENTRY (strcspn) - - movq %rdi, %rdx /* Save SRC. */ - - /* First we create a table with flags for all possible characters. - For the ASCII (7bit/8bit) or ISO-8859-X character sets which are - supported by the C string functions we have 256 characters. - Before inserting marks for the stop characters we clear the whole - table. */ - movq %rdi, %r8 /* Save value. */ - subq $256, %rsp /* Make space for 256 bytes. */ - cfi_adjust_cfa_offset(256) - movl $32, %ecx /* 32*8 bytes = 256 bytes. */ - movq %rsp, %rdi - xorl %eax, %eax /* We store 0s. */ - cld - rep - stosq - - movq %rsi, %rax /* Setup skipset. */ - -/* For understanding the following code remember that %rcx == 0 now. - Although all the following instruction only modify %cl we always - have a correct zero-extended 64-bit value in %rcx. */ - - .p2align 4 -L(2): movb (%rax), %cl /* get byte from skipset */ - testb %cl, %cl /* is NUL char? */ - jz L(1) /* yes => start compare loop */ - movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ - - movb 1(%rax), %cl /* get byte from skipset */ - testb $0xff, %cl /* is NUL char? */ - jz L(1) /* yes => start compare loop */ - movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ - - movb 2(%rax), %cl /* get byte from skipset */ - testb $0xff, %cl /* is NUL char? */ - jz L(1) /* yes => start compare loop */ - movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ - - movb 3(%rax), %cl /* get byte from skipset */ - addq $4, %rax /* increment skipset pointer */ - movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ - testb $0xff, %cl /* is NUL char? */ - jnz L(2) /* no => process next dword from skipset */ - -L(1): leaq -4(%rdx), %rax /* prepare loop */ - - /* We use a neat trick for the following loop. Normally we would - have to test for two termination conditions - 1. a character in the skipset was found - and - 2. the end of the string was found - But as a sign that the character is in the skipset we store its - value in the table. But the value of NUL is NUL so the loop - terminates for NUL in every case. */ - - .p2align 4 -L(3): addq $4, %rax /* adjust pointer for full loop round */ - - movb (%rax), %cl /* get byte from string */ - cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ - je L(4) /* yes => return */ - - movb 1(%rax), %cl /* get byte from string */ - cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ - je L(5) /* yes => return */ - - movb 2(%rax), %cl /* get byte from string */ - cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ - jz L(6) /* yes => return */ - - movb 3(%rax), %cl /* get byte from string */ - cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ - jne L(3) /* no => start loop again */ - - incq %rax /* adjust pointer */ -L(6): incq %rax -L(5): incq %rax - -L(4): addq $256, %rsp /* remove skipset */ - cfi_adjust_cfa_offset(-256) -#ifdef USE_AS_STRPBRK - xorl %edx,%edx - orb %cl, %cl /* was last character NUL? */ - cmovzq %rdx, %rax /* Yes: return NULL */ -#else - subq %rdx, %rax /* we have to return the number of valid - characters, so compute distance to first - non-valid character */ -#endif - ret -END (strcspn) -libc_hidden_builtin_def (strcspn)
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