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kc3-lang/libffi/m4/ax_gcc_x86_cpuid.m4

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  • Author : Anthony Green
    Date : 2018-03-18 13:32:03
    Hash : 81d345b2
    Message : Update autoconf archive macros

  • m4/ax_gcc_x86_cpuid.m4
  • # ===========================================================================
    #     https://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html
    # ===========================================================================
    #
    # SYNOPSIS
    #
    #   AX_GCC_X86_CPUID(OP)
    #   AX_GCC_X86_CPUID_COUNT(OP, COUNT)
    #
    # 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. AX_GCC_X86_CPUID_COUNT takes an additional COUNT
    #   parameter that gets passed into register ECX before calling cpuid.
    #
    #   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
    #   Copyright (c) 2015 Michael Petch <mpetch@capp-sysware.com>
    #
    #   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 <https://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 10
    
    AC_DEFUN([AX_GCC_X86_CPUID],
    [AX_GCC_X86_CPUID_COUNT($1, 0)
    ])
    
    AC_DEFUN([AX_GCC_X86_CPUID_COUNT],
    [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, level = $2, eax, ebx, ecx, edx;
         FILE *f;
          __asm__ __volatile__ ("xchg %%ebx, %1\n"
            "cpuid\n"
            "xchg %%ebx, %1\n"
            : "=a" (eax), "=r" (ebx), "=c" (ecx), "=d" (edx)
            : "a" (op), "2" (level));
    
         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])
    ])