sysdeps/i386/i686/memcpy.S

   1 /* Copy memory block and return pointer to beginning of destination block
   2    For Intel 80x86, x>=6.
   3    This file is part of the GNU C Library.
   4    Copyright (C) 1999, 2000, 2003 Free Software Foundation, Inc.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.
   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, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #include <sysdep.h>
  23 #include "asm-syntax.h"
  24 #include "bp-sym.h"
  25 #include "bp-asm.h"
  26
  27 #define PARMS   LINKAGE         /* no space for saved regs */
  28 #define RTN     PARMS
  29 #define DEST    RTN+RTN_SIZE
  30 #define SRC     DEST+PTR_SIZE
  31 #define LEN     SRC+PTR_SIZE
  32
  33         .text
  34 ENTRY (BP_SYM (memcpy))
  35         ENTER
  36
  37         movl    LEN(%esp), %ecx
  38         movl    %edi, %eax
  39         movl    DEST(%esp), %edi
  40         movl    %esi, %edx
  41         movl    SRC(%esp), %esi
  42         CHECK_BOUNDS_BOTH_WIDE (%edi, DEST(%esp), %ecx)
  43         CHECK_BOUNDS_BOTH_WIDE (%esi, SRC(%esp), %ecx)
  44
  45         cld
  46         shrl    $1, %ecx
  47         jnc     1f
  48         movsb
  49 1:      shrl    $1, %ecx
  50         jnc     2f
  51         movsw
  52 2:      rep
  53         movsl
  54         movl    %eax, %edi
  55         movl    %edx, %esi
  56         movl    DEST(%esp), %eax
  57         RETURN_BOUNDED_POINTER (DEST(%esp))
  58
  59         LEAVE
  60         RET_PTR
  61 END (BP_SYM (memcpy))
  62 libc_hidden_builtin_def (memcpy)