gcc/config/i386/driver-i386.c

   1 /* Subroutines for the gcc driver.
   2    Copyright (C) 2006 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC 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, or (at your option)
   9 any later version.
  10
  11 GCC 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 GCC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  19 Boston, MA 02110-1301, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include <stdlib.h>
  24
  25 const char *host_detect_local_cpu (int argc, const char **argv);
  26
  27 #ifdef GCC_VERSION
  28 #define cpuid(num,a,b,c,d) \
  29   asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \
  30                 : "=a" (a), "=r" (b), "=c" (c), "=d" (d)  \
  31                 : "0" (num))
  32
  33 #define bit_CMPXCHG8B (1 << 8)
  34 #define bit_CMOV (1 << 15)
  35 #define bit_MMX (1 << 23)
  36 #define bit_SSE (1 << 25)
  37 #define bit_SSE2 (1 << 26)
  38
  39 #define bit_SSE3 (1 << 0)
  40 #define bit_CMPXCHG16B (1 << 13)
  41
  42 #define bit_3DNOW (1 << 31)
  43 #define bit_3DNOWP (1 << 30)
  44 #define bit_LM (1 << 29)
  45
  46 /* This will be called by the spec parser in gcc.c when it sees
  47    a %:local_cpu_detect(args) construct.  Currently it will be called
  48    with either "arch" or "tune" as argument depending on if -march=native
  49    or -mtune=native is to be substituted.
  50
  51    It returns a string containing new command line parameters to be
  52    put at the place of the above two options, depending on what CPU
  53    this is executed.  E.g. "-march=k8" on an AMD64 machine
  54    for -march=native.
  55
  56    ARGC and ARGV are set depending on the actual arguments given
  57    in the spec.  */
  58 const char *host_detect_local_cpu (int argc, const char **argv)
  59 {
  60   const char *cpu = "i386";
  61   unsigned int eax, ebx, ecx, edx;
  62   unsigned int max_level;
  63   unsigned int vendor;
  64   unsigned int ext_level;
  65   unsigned char has_mmx = 0, has_3dnow = 0, has_3dnowp = 0, has_sse = 0;
  66   unsigned char has_sse2 = 0, has_sse3 = 0, has_cmov = 0;
  67   unsigned char has_longmode = 0;
  68   unsigned char is_amd = 0;
  69   unsigned int family = 0;
  70   if (argc < 1
  71       || (strcmp (argv[0], "arch")
  72           && strcmp (argv[0], "tune")))
  73     return NULL;
  74
  75 #ifndef __x86_64__
  76   /* See if we can use cpuid.  */
  77   asm volatile ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;"
  78                 "pushl %0; popfl; pushfl; popl %0; popfl"
  79                 : "=&r" (eax), "=&r" (ebx)
  80                 : "i" (0x00200000));
  81
  82   if (((eax ^ ebx) & 0x00200000) == 0)
  83     goto done;
  84 #endif
  85
  86   cpu = "i586";
  87
  88   /* Check the highest input value for eax.  */
  89   cpuid (0, eax, ebx, ecx, edx);
  90   max_level = eax;
  91   /* We only look at the first four characters.  */
  92   vendor = ebx;
  93   if (max_level == 0)
  94     goto done;
  95
  96   cpuid (1, eax, ebx, ecx, edx);
  97   has_cmov = !!(edx & bit_CMOV);
  98   has_mmx = !!(edx & bit_MMX);
  99   has_sse = !!(edx & bit_SSE);
 100   has_sse2 = !!(edx & bit_SSE2);
 101   has_sse3 = !!(ecx & bit_SSE3);
 102   /* We don't care for extended family.  */
 103   family = (eax >> 8) & ~(1 << 4);
 104
 105   cpuid (0x80000000, eax, ebx, ecx, edx);
 106   ext_level = eax;
 107   if (ext_level >= 0x80000000)
 108     {
 109       cpuid (0x80000001, eax, ebx, ecx, edx);
 110       has_3dnow = !!(edx & bit_3DNOW);
 111       has_3dnowp = !!(edx & bit_3DNOWP);
 112       has_longmode = !!(edx & bit_LM);
 113     }
 114
 115   is_amd = vendor == *(unsigned int*)"Auth";
 116
 117   if (is_amd)
 118     {
 119       if (has_mmx)
 120         cpu = "k6";
 121       if (has_3dnow)
 122         cpu = "k6-3";
 123       if (has_3dnowp)
 124         cpu = "athlon";
 125       if (has_sse)
 126         cpu = "athlon-4";
 127       if (has_sse2 || has_longmode)
 128         cpu = "k8";
 129     }
 130   else
 131     {
 132       if (family == 5)
 133         {
 134           if (has_mmx)
 135             cpu = "pentium-mmx";
 136         }
 137       else if (has_mmx)
 138         cpu = "pentium2";
 139       if (has_sse)
 140         cpu = "pentium3";
 141       if (has_sse2)
 142         {
 143           if (family == 6)
 144             /* It's a pentiumpro with sse2 --> pentium-m */
 145             cpu = "pentium-m";
 146           else
 147             /* Would have to look at extended family, but it's at least
 148                an pentium4 core.  */
 149             cpu = "pentium4";
 150         }
 151       if (has_sse3)
 152         {
 153           if (has_longmode)
 154             cpu = "nocona";
 155           else
 156             cpu = "prescott";
 157         }
 158     }
 159
 160 done:
 161   return concat ("-m", argv[0], "=", cpu, NULL);
 162 }
 163 #else
 164 /* If we aren't compiling with GCC we just provide a minimal
 165    default value.  */
 166 const char *host_detect_local_cpu (int argc, const char **argv)
 167 {
 168   return concat ("-m", argv[0], "=i386", NULL);
 169 }
 170 #endif /* GCC_VERSION */