ax_gcc_x86_cpuid.m4.htm 3.2 KB

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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. #
  9. # DESCRIPTION
  10. #
  11. # On Pentium and later x86 processors, with gcc or a compiler that has a
  12. # compatible syntax for inline assembly instructions, run a small program
  13. # that executes the cpuid instruction with input OP. This can be used to
  14. # detect the CPU type.
  15. #
  16. # On output, the values of the eax, ebx, ecx, and edx registers are stored
  17. # as hexadecimal strings as "eax:ebx:ecx:edx" in the cache variable
  18. # ax_cv_gcc_x86_cpuid_OP.
  19. #
  20. # If the cpuid instruction fails (because you are running a
  21. # cross-compiler, or because you are not using gcc, or because you are on
  22. # a processor that doesn't have this instruction), ax_cv_gcc_x86_cpuid_OP
  23. # is set to the string "unknown".
  24. #
  25. # This macro mainly exists to be used in AX_GCC_ARCHFLAG.
  26. #
  27. # LICENSE
  28. #
  29. # Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
  30. # Copyright (c) 2008 Matteo Frigo
  31. #
  32. # This program is free software: you can redistribute it and/or modify it
  33. # under the terms of the GNU General Public License as published by the
  34. # Free Software Foundation, either version 3 of the License, or (at your
  35. # option) any later version.
  36. #
  37. # This program is distributed in the hope that it will be useful, but
  38. # WITHOUT ANY WARRANTY; without even the implied warranty of
  39. # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
  40. # Public License for more details.
  41. #
  42. # You should have received a copy of the GNU General Public License along
  43. # with this program. If not, see <http://www.gnu.org/licenses/>.
  44. #
  45. # As a special exception, the respective Autoconf Macro's copyright owner
  46. # gives unlimited permission to copy, distribute and modify the configure
  47. # scripts that are the output of Autoconf when processing the Macro. You
  48. # need not follow the terms of the GNU General Public License when using
  49. # or distributing such scripts, even though portions of the text of the
  50. # Macro appear in them. The GNU General Public License (GPL) does govern
  51. # all other use of the material that constitutes the Autoconf Macro.
  52. #
  53. # This special exception to the GPL applies to versions of the Autoconf
  54. # Macro released by the Autoconf Archive. When you make and distribute a
  55. # modified version of the Autoconf Macro, you may extend this special
  56. # exception to the GPL to apply to your modified version as well.
  57. #serial 7
  58. AC_DEFUN([AX_GCC_X86_CPUID],
  59. [AC_REQUIRE([AC_PROG_CC])
  60. AC_LANG_PUSH([C])
  61. AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1,
  62. [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [
  63. int op = $1, eax, ebx, ecx, edx;
  64. FILE *f;
  65. __asm__("cpuid"
  66. : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
  67. : "a" (op));
  68. f = fopen("conftest_cpuid", "w"); if (!f) return 1;
  69. fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx);
  70. fclose(f);
  71. return 0;
  72. ])],
  73. [ax_cv_gcc_x86_cpuid_$1=`cat conftest_cpuid`; rm -f conftest_cpuid],
  74. [ax_cv_gcc_x86_cpuid_$1=unknown; rm -f conftest_cpuid],
  75. [ax_cv_gcc_x86_cpuid_$1=unknown])])
  76. AC_LANG_POP([C])
  77. ])