# ===========================================================================

#        http://www.nongnu.org/autoconf-archive/ax_gcc_x86_cpuid.html

# ===========================================================================

#

# SYNOPSIS

#

#   AX_GCC_X86_CPUID(OP)

#

# DESCRIPTION

#

#   On Pentium and later x86 processors, with gcc or a compiler that has a

#   compatible syntax for inline assembly instructions, run a small program

#   that executes the cpuid instruction with input OP. This can be used to

#   detect the CPU type.

#

#   On output, the values of the eax, ebx, ecx, and edx registers are stored

#   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable

#   ax_cv_gcc_x86_cpuid_OP.

#

#   If the cpuid instruction fails (because you are running a

#   cross-compiler, or because you are not using gcc, or because you are on

#   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP

#   is set to the string "unknown".

#

#   This macro mainly exists to be used in AX_GCC_ARCHFLAG.

#

# LICENSE

#

#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>

#   Copyright (c) 2008 Matteo Frigo

#

#   This program is free software: you can redistribute it and/or modify it

#   under the terms of the GNU General Public License as published by the

#   Free Software Foundation, either version 3 of the License, or (at your

#   option) any later version.

#

#   This program is distributed in the hope that it will be useful, but

#   WITHOUT ANY WARRANTY; without even the implied warranty of

#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

#   Public License for more details.

#

#   You should have received a copy of the GNU General Public License along

#   with this program. If not, see <http://www.gnu.org/licenses/>.

#

#   As a special exception, the respective Autoconf Macro's copyright owner

#   gives unlimited permission to copy, distribute and modify the configure

#   scripts that are the output of Autoconf when processing the Macro. You

#   need not follow the terms of the GNU General Public License when using

#   or distributing such scripts, even though portions of the text of the

#   Macro appear in them. The GNU General Public License (GPL) does govern

#   all other use of the material that constitutes the Autoconf Macro.

#

#   This special exception to the GPL applies to versions of the Autoconf

#   Macro released by the Autoconf Archive. When you make and distribute a

#   modified version of the Autoconf Macro, you may extend this special

#   exception to the GPL to apply to your modified version as well.

AC_DEFUN([AX_GCC_X86_CPUID],

[AC_REQUIRE([AC_PROG_CC])

AC_LANG_PUSH([C])

AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,

 [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [

     int op = $1, eax, ebx, ecx, edx;

     FILE *f;

      __asm__("cpuid"

        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)

        : "a" (op));

     f = fopen("conftest_cpuid", "w"); if (!f) return 1;

     fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);

     fclose(f);

     return 0;

])],

     [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],

     [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],

     [ax_cv_gcc_x86_cpuid_$1=unknown])])

AC_LANG_POP([C])

])