glibc/sysdeps/x86_64/memset.S
Adhemerval Zanella 9403b71ae9 x86_64: Remove bzero optimization
Both symbols are marked as legacy in POSIX.1-2001 and removed on
POSIX.1-2008, although the prototypes are defined for _GNU_SOURCE
or _DEFAULT_SOURCE.

GCC also replaces bcopy with a memmove and bzero with memset on default
configuration (to actually get a bzero libc call the code requires
to omit string.h inclusion and built with -fno-builtin), so it is
highly unlikely programs are actually calling libc bzero symbol.

On a recent Linux distro (Ubuntu 22.04), there is no bzero calls
by the installed binaries.

  $ cat count_bstring.sh
  #!/bin/bash

  files=`IFS=':';for i in $PATH; do test -d "$i" && find "$i" -maxdepth 1 -executable -type f; done`
  total=0
  for file in $files; do
    symbols=`objdump -R $file 2>&1`
    if [ $? -eq 0 ]; then
      ncalls=`echo $symbols | grep -w $1 | wc -l`
      ((total=total+ncalls))
      if [ $ncalls -gt 0 ]; then
        echo "$file: $ncalls"
      fi
    fi
  done
  echo "TOTAL=$total"
  $ ./count_bstring.sh bzero
  TOTAL=0

Checked on x86_64-linux-gnu.
2022-05-16 09:36:06 -03:00

70 lines
1.8 KiB
ArmAsm

/* memset -- set memory area to CH/0
Optimized version for x86-64.
Copyright (C) 2002-2022 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>
#define USE_WITH_SSE2 1
#define VEC_SIZE 16
#define MOV_SIZE 3
#define RET_SIZE 1
#define VEC(i) xmm##i
#define VMOVU movups
#define VMOVA movaps
# define MEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
movd d, %xmm0; \
movq r, %rax; \
punpcklbw %xmm0, %xmm0; \
punpcklwd %xmm0, %xmm0; \
pshufd $0, %xmm0, %xmm0
# define WMEMSET_SET_VEC0_AND_SET_RETURN(d, r) \
movd d, %xmm0; \
pshufd $0, %xmm0, %xmm0; \
movq r, %rax
# define MEMSET_VDUP_TO_VEC0_HIGH()
# define MEMSET_VDUP_TO_VEC0_LOW()
# define WMEMSET_VDUP_TO_VEC0_HIGH()
# define WMEMSET_VDUP_TO_VEC0_LOW()
#define SECTION(p) p
#ifndef MEMSET_SYMBOL
# define MEMSET_CHK_SYMBOL(p,s) p
# define MEMSET_SYMBOL(p,s) memset
#endif
#ifndef WMEMSET_SYMBOL
# define WMEMSET_CHK_SYMBOL(p,s) p
# define WMEMSET_SYMBOL(p,s) __wmemset
#endif
#include "multiarch/memset-vec-unaligned-erms.S"
libc_hidden_builtin_def (memset)
#if IS_IN (libc)
libc_hidden_def (__wmemset)
weak_alias (__wmemset, wmemset)
libc_hidden_weak (wmemset)
#endif