sysdeps/x86_64/rtld-memset.S

   1 /* memset implementation for the dynamic linker.  This is separate from the
   2    libc implementation to avoid writing to SSE registers.
   3    Copyright (C) 2013-2014 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <sysdep.h>
  21 #include "asm-syntax.h"
  22
  23
  24         .text
  25 /* void *memset (void *dest, char c, size_t count)
  26    dest  => %rdi
  27    c     => %rsi
  28    count => %rdx  */
  29 ENTRY (memset)
  30         mov     %rdx, %rcx
  31         movzbl  %sil, %eax
  32         mov     %rdi, %rdx
  33         rep     stosb
  34         mov     %rdx, %rax
  35         ret
  36 END (memset)
  37 libc_hidden_builtin_def (memset)