author Sam Lantinga <>
Tue, 18 Jan 2011 22:40:45 -0800
changeset 5029 5d7d48157be7
permissions -rw-r--r--
Greg Jandl to SDL I did some digging, and I think I've found a better solution. By including some additional .m4 macros in the acinclude directory (, and then using the patch below (same as previous patch + one line change to, SDL will build correctly out of the box. The arch can then be overridden by --with-gcc-arch=<arch> (most will probably want to build with i686 there for general distribution) or --without-gcc-arch, to disable setting the arch all together. On my Atom netbook, I get -march=PentiumPro by default, which works great, as does --with-gcc-arch=i686.

# ===========================================================================
# ===========================================================================
#   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.
#   Copyright (c) 2008 Steven G. Johnson <>
#   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
#   Public License for more details.
#   You should have received a copy of the GNU General Public License along
#   with this program. If not, see <>.
#   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_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;
        : "=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);
     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],