src/mesa/x86/common_x86.c

   1 /* $Id: common_x86.c,v 1.14 2001/03/28 20:44:43 gareth Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  3.5
   6  *
   7  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27 /*
  28  * Check CPU capabilities & initialize optimized funtions for this particular
  29  * processor.
  30  *
  31  * Written by Holger Waechtler <holger@akaflieg.extern.tu-berlin.de>
  32  * Changed by Andre Werthmann <wertmann@cs.uni-potsdam.de> for using the
  33  * new Katmai functions.
  34  */
  35
  36 #include <stdlib.h>
  37 #include <stdio.h>
  38 #if defined(USE_KATMAI_ASM) && defined(__linux__)
  39 #include <signal.h>
  40 #endif
  41
  42 #include "context.h"
  43 #include "common_x86_asm.h"
  44
  45
  46 int _mesa_x86_cpu_features = 0;
  47
  48 /* No reason for this to be public.
  49  */
  50 extern int _mesa_identify_x86_cpu_features( void );
  51
  52
  53 static void message( const char *msg )
  54 {
  55    GLboolean debug;
  56 #ifdef DEBUG
  57    debug = GL_TRUE;
  58 #else
  59    if ( getenv( "MESA_DEBUG" ) ) {
  60       debug = GL_TRUE;
  61    } else {
  62       debug = GL_FALSE;
  63    }
  64 #endif
  65    if ( debug ) {
  66       fprintf( stderr, "%s", msg );
  67    }
  68 }
  69
  70 #if defined(USE_KATMAI_ASM)
  71 /*
  72  * We must verify that the Streaming SIMD Extensions are truly supported
  73  * on this processor before we go ahead and hook out the optimized code.
  74  * Unfortunately, the CPUID bit isn't enough, as the OS must set the
  75  * OSFXSR bit in CR4 if it supports the extended FPU save and restore
  76  * required to use SSE.  Unfortunately, we can't just go ahead and read
  77  * this register, as only the kernel can do that.  Similarly, we must
  78  * verify that the OSXMMEXCPT bit in CR4 has been set by the OS,
  79  * signifying that it supports unmasked SIMD FPU exceptions.  If we take
  80  * an unmasked exception and the OS doesn't correctly support them, the
  81  * best we'll get is a SIGILL and the worst we'll get is an infinite
  82  * loop in the signal delivery from the kernel as we can't interact with
  83  * the SIMD FPU state to clear the exception bits.  Either way, this is
  84  * not good.
  85  */
  86
  87 extern void _mesa_test_os_katmai_support( void );
  88 extern void _mesa_test_os_katmai_exception_support( void );
  89
  90 #if defined(__linux__) && defined(_POSIX_SOURCE)
  91 static void sigill_handler( int signal, struct sigcontext sc )
  92 {
  93    message( "SIGILL, " );
  94
  95    /* Both the "xorps %%xmm0,%%xmm0" and "divps %xmm0,%%xmm1"
  96     * instructions are 3 bytes long.  We must increment the instruction
  97     * pointer manually to avoid repeated execution of the offending
  98     * instruction.
  99     *
 100     * If the SIGILL is caused by a divide-by-zero when unmasked
 101     * exceptions aren't supported, the SIMD FPU status and control
 102     * word will be restored at the end of the test, so we don't need
 103     * to worry about doing it here.  Besides, we may not be able to...
 104     */
 105    sc.eip += 3;
 106
 107    _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 108 }
 109
 110 static void sigfpe_handler( int signal, struct sigcontext sc )
 111 {
 112    message( "SIGFPE, " );
 113
 114    if ( sc.fpstate->magic != 0xffff ) {
 115       /* Our signal context has the extended FPU state, so reset the
 116        * divide-by-zero exception mask and clear the divide-by-zero
 117        * exception bit.
 118        */
 119       sc.fpstate->mxcsr |= 0x00000200;
 120       sc.fpstate->mxcsr &= 0xfffffffb;
 121    } else {
 122       /* If we ever get here, we're completely hosed.
 123        */
 124       message( "\n\n" );
 125       _mesa_problem( NULL, "SSE enabling test failed badly!" );
 126    }
 127 }
 128 #endif /* __linux__ && _POSIX_SOURCE */
 129
 130 /* If we're running on a processor that can do SSE, let's see if we
 131  * are allowed to or not.  This will catch 2.4.0 or later kernels that
 132  * haven't been configured for a Pentium III but are running on one,
 133  * and RedHat patched 2.2 kernels that have broken exception handling
 134  * support for user space apps that do SSE.
 135  *
 136  * GH: Isn't this just awful?
 137  */
 138 static void check_os_katmai_support( void )
 139 {
 140 #if defined(__linux__)
 141 #if defined(_POSIX_SOURCE)
 142    struct sigaction saved_sigill;
 143    struct sigaction saved_sigfpe;
 144
 145    /* Save the original signal handlers.
 146     */
 147    sigaction( SIGILL, NULL, &saved_sigill );
 148    sigaction( SIGFPE, NULL, &saved_sigfpe );
 149
 150    signal( SIGILL, (void (*)(int))sigill_handler );
 151    signal( SIGFPE, (void (*)(int))sigfpe_handler );
 152
 153    /* Emulate test for OSFXSR in CR4.  The OS will set this bit if it
 154     * supports the extended FPU save and restore required for SSE.  If
 155     * we execute an SSE instruction on a PIII and get a SIGILL, the OS
 156     * doesn't support Streaming SIMD Exceptions, even if the processor
 157     * does.
 158     */
 159    if ( cpu_has_xmm ) {
 160       message( "Testing OS support for SSE... " );
 161
 162       _mesa_test_os_katmai_support();
 163
 164       if ( cpu_has_xmm ) {
 165          message( "yes.\n" );
 166       } else {
 167          message( "no!\n" );
 168       }
 169    }
 170
 171    /* Emulate test for OSXMMEXCPT in CR4.  The OS will set this bit if
 172     * it supports unmasked SIMD FPU exceptions.  If we unmask the
 173     * exceptions, do a SIMD divide-by-zero and get a SIGILL, the OS
 174     * doesn't support unmasked SIMD FPU exceptions.  If we get a SIGFPE
 175     * as expected, we're okay but we need to clean up after it.
 176     *
 177     * Are we being too stringent in our requirement that the OS support
 178     * unmasked exceptions?  Certain RedHat 2.2 kernels enable SSE by
 179     * setting CR4.OSFXSR but don't support unmasked exceptions.  Win98
 180     * doesn't even support them.  We at least know the user-space SSE
 181     * support is good in kernels that do support unmasked exceptions,
 182     * and therefore to be safe I'm going to leave this test in here.
 183     */
 184    if ( cpu_has_xmm ) {
 185       message( "Testing OS support for SSE unmasked exceptions... " );
 186
 187       _mesa_test_os_katmai_exception_support();
 188
 189       if ( cpu_has_xmm ) {
 190          message( "yes.\n" );
 191       } else {
 192          message( "no!\n" );
 193       }
 194    }
 195
 196    /* Restore the original signal handlers.
 197     */
 198    sigaction( SIGILL, &saved_sigill, NULL );
 199    sigaction( SIGFPE, &saved_sigfpe, NULL );
 200
 201    /* If we've gotten to here and the XMM CPUID bit is still set, we're
 202     * safe to go ahead and hook out the SSE code throughout Mesa.
 203     */
 204    if ( cpu_has_xmm ) {
 205       message( "Tests of OS support for SSE passed.\n" );
 206    } else {
 207       message( "Tests of OS support for SSE failed!\n" );
 208    }
 209 #else
 210    /* We can't use POSIX signal handling to test the availability of
 211     * SSE, so we disable it by default.
 212     */
 213    message( "Cannot test OS support for SSE, disabling to be safe.\n" );
 214    _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 215 #endif /* _POSIX_SOURCE */
 216 #else
 217    /* Do nothing on non-Linux platforms for now.
 218     */
 219    message( "Not testing OS support for SSE, leaving enabled.\n" );
 220 #endif /* __linux__ */
 221 }
 222
 223 #endif /* USE_KATMAI_ASM */
 224
 225
 226 void _mesa_init_all_x86_transform_asm( void )
 227 {
 228 #ifdef USE_X86_ASM
 229    _mesa_x86_cpu_features = _mesa_identify_x86_cpu_features();
 230
 231    if ( getenv( "MESA_NO_ASM" ) ) {
 232       _mesa_x86_cpu_features = 0;
 233    }
 234
 235    if ( _mesa_x86_cpu_features ) {
 236       _mesa_init_x86_transform_asm();
 237    }
 238
 239 #ifdef USE_MMX_ASM
 240    if ( cpu_has_mmx ) {
 241       if ( getenv( "MESA_NO_MMX" ) == 0 ) {
 242          message( "MMX cpu detected.\n" );
 243       } else {
 244          _mesa_x86_cpu_features &= ~(X86_FEATURE_MMX);
 245       }
 246    }
 247 #endif
 248
 249 #ifdef USE_3DNOW_ASM
 250    if ( cpu_has_3dnow ) {
 251       if ( getenv( "MESA_NO_3DNOW" ) == 0 ) {
 252          message( "3DNow! cpu detected.\n" );
 253          _mesa_init_3dnow_transform_asm();
 254       } else {
 255          _mesa_x86_cpu_features &= ~(X86_FEATURE_3DNOW);
 256       }
 257    }
 258 #endif
 259
 260 #ifdef USE_KATMAI_ASM
 261    if ( cpu_has_xmm && getenv( "MESA_FORCE_KATMAI" ) == 0 ) {
 262       check_os_katmai_support();
 263    }
 264    if ( cpu_has_xmm ) {
 265       if ( getenv( "MESA_NO_KATMAI" ) == 0 ) {
 266          message( "Katmai cpu detected.\n" );
 267          _mesa_init_katmai_transform_asm();
 268       } else {
 269          _mesa_x86_cpu_features &= ~(X86_FEATURE_XMM);
 270       }
 271    }
 272 #endif
 273 #endif
 274 }
 275
 276 /* Note: the above function must be called before this one, so that
 277  * _mesa_x86_cpu_features gets correctly initialized.
 278  */
 279 void _mesa_init_all_x86_vertex_asm( void )
 280 {
 281 #ifdef USE_X86_ASM
 282    if ( _mesa_x86_cpu_features ) {
 283       _mesa_init_x86_vertex_asm();
 284    }
 285
 286 #ifdef USE_3DNOW_ASM
 287    if ( cpu_has_3dnow && getenv( "MESA_NO_3DNOW" ) == 0 ) {
 288       _mesa_init_3dnow_vertex_asm();
 289    }
 290 #endif
 291
 292 #ifdef USE_KATMAI_ASM
 293    if ( cpu_has_xmm && getenv( "MESA_NO_KATMAI" ) == 0 ) {
 294       _mesa_init_katmai_vertex_asm();
 295    }
 296 #endif
 297 #endif
 298 }