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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#   AX_GCC_X86_CPUID_COUNT(OP, COUNT)
9#
10# DESCRIPTION
11#
12#   On Pentium and later x86 processors, with gcc or a compiler that has a
13#   compatible syntax for inline assembly instructions, run a small program
14#   that executes the cpuid instruction with input OP. This can be used to
15#   detect the CPU type. AX_GCC_X86_CPUID_COUNT takes an additional COUNT
16#   parameter that gets passed into register ECX before calling cpuid.
17#
18#   On output, the values of the eax, ebx, ecx, and edx registers are stored
19#   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
20#   ax_cv_gcc_x86_cpuid_OP.
21#
22#   If the cpuid instruction fails (because you are running a
23#   cross-compiler, or because you are not using gcc, or because you are on
24#   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
25#   is set to the string "unknown".
26#
27#   This macro mainly exists to be used in AX_GCC_ARCHFLAG.
28#
29# LICENSE
30#
31#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
32#   Copyright (c) 2008 Matteo Frigo
33#   Copyright (c) 2015 Michael Petch <mpetch@capp-sysware.com>
34#
35#   This program is free software: you can redistribute it and/or modify it
36#   under the terms of the GNU General Public License as published by the
37#   Free Software Foundation, either version 3 of the License, or (at your
38#   option) any later version.
39#
40#   This program is distributed in the hope that it will be useful, but
41#   WITHOUT ANY WARRANTY; without even the implied warranty of
42#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
43#   Public License for more details.
44#
45#   You should have received a copy of the GNU General Public License along
46#   with this program. If not, see <http://www.gnu.org/licenses/>.
47#
48#   As a special exception, the respective Autoconf Macro's copyright owner
49#   gives unlimited permission to copy, distribute and modify the configure
50#   scripts that are the output of Autoconf when processing the Macro. You
51#   need not follow the terms of the GNU General Public License when using
52#   or distributing such scripts, even though portions of the text of the
53#   Macro appear in them. The GNU General Public License (GPL) does govern
54#   all other use of the material that constitutes the Autoconf Macro.
55#
56#   This special exception to the GPL applies to versions of the Autoconf
57#   Macro released by the Autoconf Archive. When you make and distribute a
58#   modified version of the Autoconf Macro, you may extend this special
59#   exception to the GPL to apply to your modified version as well.
60
61#serial 8
62
63AC_DEFUN([AX_GCC_X86_CPUID],
64[AX_GCC_X86_CPUID_COUNT($1, 0)
65])
66
67AC_DEFUN([AX_GCC_X86_CPUID_COUNT],
68[AC_REQUIRE([AC_PROG_CC])
69AC_LANG_PUSH([C])
70AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
71 [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
72     int op = $1, level = $2, eax, ebx, ecx, edx;
73     FILE *f;
74      __asm__ __volatile__ ("cpuid"
75        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
76        : "a" (op), "2" (level));
77
78     f = fopen("conftest_cpuid", "w"); if (!f) return 1;
79     fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
80     fclose(f);
81     return 0;
82])],
83     [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
84     [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
85     [ax_cv_gcc_x86_cpuid_$1=unknown])])
86AC_LANG_POP([C])
87])
88