acinclude/ax_gcc_x86_cpuid.m4
changeset 12190 04650c2fe44e
parent 5029 5d7d48157be7
equal deleted inserted replaced
12189:bd18236f41b5 12190:04650c2fe44e
       
     1 # ===========================================================================
       
     2 #     http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html
       
     3 # ===========================================================================
       
     4 #
       
     5 # SYNOPSIS
       
     6 #
       
     7 #   AX_GCC_X86_CPUID(OP)
       
     8 #
       
     9 # DESCRIPTION
       
    10 #
       
    11 #   On Pentium and later x86 processors, with gcc or a compiler that has a
       
    12 #   compatible syntax for inline assembly instructions, run a small program
       
    13 #   that executes the cpuid instruction with input OP. This can be used to
       
    14 #   detect the CPU type.
       
    15 #
       
    16 #   On output, the values of the eax, ebx, ecx, and edx registers are stored
       
    17 #   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
       
    18 #   ax_cv_gcc_x86_cpuid_OP.
       
    19 #
       
    20 #   If the cpuid instruction fails (because you are running a
       
    21 #   cross-compiler, or because you are not using gcc, or because you are on
       
    22 #   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
       
    23 #   is set to the string "unknown".
       
    24 #
       
    25 #   This macro mainly exists to be used in AX_GCC_ARCHFLAG.
       
    26 #
       
    27 # LICENSE
       
    28 #
       
    29 #   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
       
    30 #   Copyright (c) 2008 Matteo Frigo
       
    31 #
       
    32 #   This program is free software: you can redistribute it and/or modify it
       
    33 #   under the terms of the GNU General Public License as published by the
       
    34 #   Free Software Foundation, either version 3 of the License, or (at your
       
    35 #   option) any later version.
       
    36 #
       
    37 #   This program is distributed in the hope that it will be useful, but
       
    38 #   WITHOUT ANY WARRANTY; without even the implied warranty of
       
    39 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
       
    40 #   Public License for more details.
       
    41 #
       
    42 #   You should have received a copy of the GNU General Public License along
       
    43 #   with this program. If not, see <http://www.gnu.org/licenses/>.
       
    44 #
       
    45 #   As a special exception, the respective Autoconf Macro's copyright owner
       
    46 #   gives unlimited permission to copy, distribute and modify the configure
       
    47 #   scripts that are the output of Autoconf when processing the Macro. You
       
    48 #   need not follow the terms of the GNU General Public License when using
       
    49 #   or distributing such scripts, even though portions of the text of the
       
    50 #   Macro appear in them. The GNU General Public License (GPL) does govern
       
    51 #   all other use of the material that constitutes the Autoconf Macro.
       
    52 #
       
    53 #   This special exception to the GPL applies to versions of the Autoconf
       
    54 #   Macro released by the Autoconf Archive. When you make and distribute a
       
    55 #   modified version of the Autoconf Macro, you may extend this special
       
    56 #   exception to the GPL to apply to your modified version as well.
       
    57 
       
    58 #serial 7
       
    59 
       
    60 AC_DEFUN([AX_GCC_X86_CPUID],
       
    61 [AC_REQUIRE([AC_PROG_CC])
       
    62 AC_LANG_PUSH([C])
       
    63 AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
       
    64  [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
       
    65      int op = $1, eax, ebx, ecx, edx;
       
    66      FILE *f;
       
    67       __asm__("cpuid"
       
    68         : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
       
    69         : "a" (op));
       
    70      f = fopen("conftest_cpuid", "w"); if (!f) return 1;
       
    71      fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
       
    72      fclose(f);
       
    73      return 0;
       
    74 ])],
       
    75      [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
       
    76      [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
       
    77      [ax_cv_gcc_x86_cpuid_$1=unknown])])
       
    78 AC_LANG_POP([C])
       
    79 ])