reactos/ntoskrnl/ke/i386/fpu.c

   1 /* $Id: fpu.c,v 1.12 2003/12/30 18:52:04 fireball Exp $
   2  *
   3  *  ReactOS kernel
   4  *  Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program 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
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 /*
  21  * PROJECT:         ReactOS kernel
  22  * FILE:            ntoskrnl/ke/i386/fpu.c
  23  * PURPOSE:         Handles the FPU
  24  * PROGRAMMER:      David Welch (welch@mcmail.com)
  25  * UPDATE HISTORY:
  26  *                  Created 22/05/98
  27  */
  28
  29 /* INCLUDES *****************************************************************/
  30
  31 #include <ddk/ntddk.h>
  32 #include <internal/ke.h>
  33 #include <internal/mm.h>
  34 #include <internal/ps.h>
  35
  36 #define NDEBUG
  37 #include <internal/debug.h>
  38
  39 /* GLOBALS *******************************************************************/
  40
  41 ULONG HardwareMathSupport;
  42
  43 /* FUNCTIONS *****************************************************************/
  44
  45 VOID INIT_FUNCTION
  46 KiCheckFPU(VOID)
  47 {
  48    unsigned short int status;
  49    int cr0_;
  50
  51    HardwareMathSupport = 0;
  52
  53 #if defined(__GNUC__)
  54    __asm__("movl %%cr0, %0\n\t" : "=a" (cr0_));
  55    /* Set NE and MP. */
  56    cr0_ = cr0_ | 0x22;
  57    /* Clear EM */
  58    cr0_ = cr0_ & (~0x4);
  59    __asm__("movl %0, %%cr0\n\t" : : "a" (cr0_));
  60
  61    __asm__("clts\n\t");
  62    __asm__("fninit\n\t");
  63    __asm__("fstsw %0\n\t" : "=a" (status));
  64    if (status != 0)
  65      {
  66         __asm__("movl %%cr0, %0\n\t" : "=a" (cr0_));
  67         /* Set the EM flag in CR0 so any FPU instructions cause a trap. */
  68         cr0_ = cr0_ | 0x4;
  69         __asm__("movl %0, %%cr0\n\t" :
  70                 : "a" (cr0_));
  71         return;
  72      }
  73    /* fsetpm for i287, ignored by i387 */
  74    __asm__(".byte 0xDB, 0xE4\n\t");
  75 #elif defined(_MSC_VER)
  76    __asm mov eax, cr0;
  77    __asm mov cr0_, eax;
  78    cr0_ |= 0x22;        /* Set NE and MP. */
  79    cr0_ &= ~0x4;        /* Clear EM */
  80    __asm
  81    {
  82            mov eax, cr0_;
  83            mov cr0, eax;
  84            clts;
  85            fninit;
  86            fstsw status
  87    }
  88    if (status != 0)
  89      {
  90         __asm mov eax, cr0_;
  91         __asm or eax, 4; /* Set the EM flag in CR0 so any FPU instructions cause a trap. */
  92         __asm mov cr0, eax;
  93         return;
  94      }
  95    /* fsetpm for i287, ignored by i387 */
  96    __asm _emit 0xDB __asm _emit 0xe4
  97 //   __asm fsetpm;
  98 //   __asm__(".byte 0xDB, 0xE4\n\t");
  99 #else
 100 #error Unknown compiler for inline assembler
 101 #endif
 102
 103    HardwareMathSupport = 1;
 104 }
 105
 106 /* This is a rather naive implementation of Ke(Save/Restore)FloatingPointState
 107    which will not work for WDM drivers. Please feel free to improve */
 108
 109 #define FPU_STATE_SIZE 108
 110
 111 NTSTATUS STDCALL
 112 KeSaveFloatingPointState(OUT PKFLOATING_SAVE Save)
 113 {
 114   char *FpState;
 115
 116   FpState = ExAllocatePool(PagedPool, FPU_STATE_SIZE);
 117   if (NULL == FpState)
 118     {
 119       return STATUS_INSUFFICIENT_RESOURCES;
 120     }
 121   *((PVOID *) Save) = FpState;
 122
 123 #if defined(__GNUC__)
 124   __asm__("fsave %0\n\t" : "=m" (*FpState));
 125 #elif defined(_MSC_VER)
 126   __asm mov eax, FpState;
 127   __asm fsave [eax];
 128 #else
 129 #error Unknown compiler for inline assembler
 130 #endif
 131
 132   return STATUS_SUCCESS;
 133 }
 134
 135 NTSTATUS STDCALL
 136 KeRestoreFloatingPointState(IN PKFLOATING_SAVE Save)
 137 {
 138   char *FpState = *((PVOID *) Save);
 139
 140 #if defined(__GNUC__)
 141   __asm__("frstor %0\n\t" : "=m" (*FpState));
 142 #elif defined(_MSC_VER)
 143   __asm mov eax, FpState;
 144   __asm frstor [eax];
 145 #else
 146 #error Unknown compiler for inline assembler
 147 #endif
 148
 149   ExFreePool(FpState);
 150
 151   return STATUS_SUCCESS;
 152 }