arch/i386-all/stdc/sse.c

   1 /*-
   2  * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/lib/msun/i387/fenv.c,v 1.3 2007/01/05 07:15:26 das Exp $
  27  */
  28
  29 #include "fenv.h"
  30
  31 enum __sse_support __has_sse =
  32 #ifdef __SSE__
  33         __SSE_YES;
  34 #else
  35         __SSE_UNK;
  36 #endif
  37
  38 #define getfl(x)        __asm __volatile("pushfl\n\tpopl %0" : "=mr" (*(x)))
  39 #define setfl(x)        __asm __volatile("pushl %0\n\tpopfl" : : "g" (x))
  40 #define cpuid_dx(x)     __asm __volatile("pushl %%ebx\n\tmovl $1, %%eax\n\t"  \
  41                                          "cpuid\n\tpopl %%ebx"                \
  42                                         : "=d" (*(x)) : : "eax", "ecx")
  43
  44 /*
  45  * Test for SSE support on this processor.  We need to do this because
  46  * we need to use ldmxcsr/stmxcsr to get correct results if any part
  47  * of the program was compiled to use SSE floating-point, but we can't
  48  * use SSE on older processors.
  49  */
  50 int
  51 __test_sse(void)
  52 {
  53 #if (0)
  54     struct StdCIntBase *StdCBase =
  55         (struct StdCIntBase *)__aros_getbase_StdCBase();
  56 #endif
  57         int flag, nflag;
  58         int dx_features;
  59
  60         /* Am I a 486? */
  61         getfl(&flag);
  62         nflag = flag ^ 0x200000;
  63         setfl(nflag);
  64         getfl(&nflag);
  65         if (flag != nflag) {
  66                 /* Not a 486, so CPUID should work. */
  67                 cpuid_dx(&dx_features);
  68                 if (dx_features & 0x2000000) {
  69                         __has_sse = __SSE_YES;
  70                         return (1);
  71                 }
  72         }
  73         __has_sse = __SSE_NO;
  74         return (0);
  75 }