reactos/lib/rtl/i386/ftol_asm.s

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS kernel
   4  * PURPOSE:           Run-Time Library
   5  * FILE:              lib/rtl/i386/ftol.S
   6  * PROGRAMER:         Alex Ionescu (alex@relsoft.net)
   7  *                    Eric Kohl (ekohl@rz-online.de)
   8  *
   9  * Copyright (C) 2002 Michael Ringgaard.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  *
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. Neither the name of the project nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES// LOSS OF USE, DATA, OR PROFITS// OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  */
  37
  38 .globl __ftol
  39
  40 .intel_syntax noprefix
  41
  42 /* FUNCTIONS ***************************************************************/
  43
  44 /*
  45  * This routine is called by MSVC-generated code to convert from floating point
  46  * to integer representation. The floating point number to be converted is
  47  * on the top of the floating point stack.
  48  */
  49 __ftol:
  50     /* Set up stack frame */
  51     push ebp
  52     mov ebp, esp
  53
  54     /* Set "round towards zero" mode */
  55     fstcw [ebp-2]
  56     wait
  57     mov ax, [ebp-2]
  58     or ah, 0xC
  59     mov [ebp-4], ax
  60     fldcw [ebp-4]
  61
  62     /* Do the conversion */
  63     fistp qword ptr [ebp-12]
  64
  65     /* Restore rounding mode */
  66     fldcw [ebp-2]
  67
  68     /* Return value */
  69     mov eax, [ebp-12]
  70     mov edx, [ebp-8]
  71
  72     /* Remove stack frame and return*/
  73     leave
  74     ret