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