reactos/ntoskrnl/ke/i386/i386-mcount.S

   1 /* i386-specific implemetation of profiling support.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    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    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 /* We need a special version of the `mcount' function since for ix86 it
  22    must not clobber any register.  This has several reasons:
  23      - there is a bug in gcc as of version 2.7.2.2 which prohibits the
  24        use of profiling together with nested functions
  25      - the ELF `fixup' function uses GCC's regparm feature
  26      - some (future) systems might want to pass parameters in registers.  */
  27 /* dwelch: Altered for ReactOS to output the files to port 0xe9 for processing
  28         by bochs. */
  29
  30
  31 .globl _mcount
  32 _mcount:
  33         /* Save the caller-clobbered registers.  */
  34         pushl   %eax
  35         pushl   %ecx
  36         pushl   %edx
  37
  38         movw    $0xe9, %dx
  39         movl    4(%ebp), %eax
  40         outl    %eax, %dx
  41         movl    12(%esp), %eax
  42         outl    %eax, %dx
  43
  44         /* Pop the saved registers.  Please note that `mcount' has no
  45            return value.  */
  46         popl    %edx
  47         popl    %ecx
  48         popl    %eax
  49         ret
  50
  51
  52