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

# http://www.gnu.org/software/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.

#serial 7

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])

])