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46 lines
1.7 KiB
Plaintext
46 lines
1.7 KiB
Plaintext
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dnl @synopsis AX_GCC_X86_CPUID(OP)
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dnl
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dnl @summary run x86 cpuid instruction OP using gcc inline assembler
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dnl
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dnl On Pentium and later x86 processors, with gcc or a compiler that
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dnl has a compatible syntax for inline assembly instructions, run a
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dnl small program that executes the cpuid instruction with input OP.
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dnl This can be used to detect the CPU type.
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dnl
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dnl On output, the values of the eax, ebx, ecx, and edx registers are
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dnl stored as hexadecimal strings as "eax:ebx:ecx:edx" in the cache
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dnl variable ax_cv_gcc_x86_cpuid_OP.
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dnl
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dnl If the cpuid instruction fails (because you are running a
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dnl cross-compiler, or because you are not using gcc, or because you
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dnl are on a processor that doesn't have this instruction),
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dnl ax_cv_gcc_x86_cpuid_OP is set to the string "unknown".
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dnl
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dnl This macro mainly exists to be used in AX_GCC_ARCHFLAG.
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dnl
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dnl @category Misc
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dnl @author Steven G. Johnson <stevenj@alum.mit.edu> and Matteo Frigo.
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dnl @version 2005-05-30
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dnl @license GPLWithACException
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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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])
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