acinclude/ax_gcc_x86_cpuid.m4.htm
author Michael Sartain <mikesart@valvesoftware.com>
Thu, 11 Oct 2012 09:41:43 -0700
changeset 6570 45855398762c
parent 5029 5d7d48157be7
permissions -rw-r--r--
Add GLX_X_VISUAL_TYPE_EXT so created window will use DirectColor if available (instead of TrueColor).
Our new X11 window was being created with the TrueColor attribute, and trying to set the gamma
on that would fail. This change checks for the visual_info extension, and uses that to ask for
DirectColor if available.
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# ===========================================================================
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#     http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html
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# ===========================================================================
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#
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# SYNOPSIS
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#
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#   AX_GCC_X86_CPUID(OP)
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#
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# DESCRIPTION
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#
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#   On Pentium and later x86 processors, with gcc or a compiler that has a
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#   compatible syntax for inline assembly instructions, run a small program
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#   that executes the cpuid instruction with input OP. This can be used to
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#   detect the CPU type.
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#
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#   On output, the values of the eax, ebx, ecx, and edx registers are stored
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#   as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
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#   ax_cv_gcc_x86_cpuid_OP.
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#
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#   If the cpuid instruction fails (because you are running a
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#   cross-compiler, or because you are not using gcc, or because you are on
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#   a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
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#   is set to the string "unknown".
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#
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#   This macro mainly exists to be used in AX_GCC_ARCHFLAG.
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#
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# LICENSE
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#
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#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
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#   Copyright (c) 2008 Matteo Frigo
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#
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#   This program is free software: you can redistribute it and/or modify it
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#   under the terms of the GNU General Public License as published by the
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#   Free Software Foundation, either version 3 of the License, or (at your
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#   option) any later version.
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#
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#   This program is distributed in the hope that it will be useful, but
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#   WITHOUT ANY WARRANTY; without even the implied warranty of
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#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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#   Public License for more details.
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#
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#   You should have received a copy of the GNU General Public License along
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#   with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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#   As a special exception, the respective Autoconf Macro's copyright owner
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#   gives unlimited permission to copy, distribute and modify the configure
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#   scripts that are the output of Autoconf when processing the Macro. You
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#   need not follow the terms of the GNU General Public License when using
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#   or distributing such scripts, even though portions of the text of the
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#   Macro appear in them. The GNU General Public License (GPL) does govern
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#   all other use of the material that constitutes the Autoconf Macro.
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#
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#   This special exception to the GPL applies to versions of the Autoconf
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#   Macro released by the Autoconf Archive. When you make and distribute a
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#   modified version of the Autoconf Macro, you may extend this special
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#   exception to the GPL to apply to your modified version as well.
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#serial 7
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AC_DEFUN([AX_GCC_X86_CPUID],
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[AC_REQUIRE([AC_PROG_CC])
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AC_LANG_PUSH([C])
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AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
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 [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
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     int op = $1, eax, ebx, ecx, edx;
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     FILE *f;
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      __asm__("cpuid"
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        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
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        : "a" (op));
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     f = fopen("conftest_cpuid", "w"); if (!f) return 1;
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     fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
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     fclose(f);
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     return 0;
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])],
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     [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
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     [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
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     [ax_cv_gcc_x86_cpuid_$1=unknown])])
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AC_LANG_POP([C])
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])