sysdeps/i386/i686/mempcpy.S

   1 /* Copy memory block and return pointer to following byte.
   2    For Intel 80x86, x>=6.
   3    This file is part of the GNU C Library.
   4    Copyright (C) 1998-2019 Free Software Foundation, Inc.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <https://www.gnu.org/licenses/>.  */
  20
  21 #include <sysdep.h>
  22 #include "asm-syntax.h"
  23
  24 #define PARMS   4               /* no space for saved regs */
  25 #define RTN     PARMS
  26 #define DEST    RTN
  27 #define SRC     DEST+4
  28 #define LEN     SRC+4
  29
  30         .text
  31 #if defined PIC && IS_IN (libc)
  32 ENTRY_CHK (__mempcpy_chk)
  33         movl    12(%esp), %eax
  34         cmpl    %eax, 16(%esp)
  35         jb      HIDDEN_JUMPTARGET (__chk_fail)
  36 END_CHK (__mempcpy_chk)
  37 #endif
  38 ENTRY (__mempcpy)
  39
  40         movl    LEN(%esp), %ecx
  41         movl    %edi, %eax
  42         cfi_register (edi, eax)
  43         movl    DEST(%esp), %edi
  44         movl    %esi, %edx
  45         cfi_register (esi, edx)
  46         movl    SRC(%esp), %esi
  47         cld
  48         shrl    $1, %ecx
  49         jnc     1f
  50         movsb
  51 1:      shrl    $1, %ecx
  52         jnc     2f
  53         movsw
  54 2:      rep
  55         movsl
  56         xchgl   %edi, %eax
  57         cfi_restore (edi)
  58         movl    %edx, %esi
  59         cfi_restore (esi)
  60
  61         ret
  62 END (__mempcpy)
  63 libc_hidden_def (__mempcpy)
  64 weak_alias (__mempcpy, mempcpy)
  65 libc_hidden_builtin_def (mempcpy)