/* $Id: x86_cpuinfo.c,v 1.1 2004/05/22 20:59:58 mikpe Exp $

 * Copyright (C) 2004  Mikael Pettersson

 */

#include <string.h>

#include "x86_cpuinfo.h"

struct cpuid { /* The field order must not be changed. */

    unsigned int eax, ebx, edx, ecx;

};

#ifdef __x86_64__

static void get_cpuid(unsigned int op, struct cpuid *cpuid)

{

    __asm__("cpuid"

	    : "=a"(cpuid->eax),

	      "=b"(cpuid->ebx),

	      "=c"(cpuid->ecx),

	      "=d"(cpuid->edx)

	    : "0"(op));

}

#else

/* Many versions of gcc fail on x86 if an asm() clobbers %ebx when

   -fPIC is specified. So we do the cpuid in hand-written assembly code. */

extern void get_cpuid(unsigned int, struct cpuid*); /* x86_cpuid.S */

#endif

static const struct {

    const char vendor_string[12];

    unsigned int vendor_code;

} vendors[] = {

    { "GenuineIntel", X86_VENDOR_INTEL },

    { "AuthenticAMD", X86_VENDOR_AMD },

    { "CyrixInstead", X86_VENDOR_CYRIX },

    { "CentaurHauls", X86_VENDOR_CENTAUR },

};

static unsigned int check_vendor(const char cpuid_vendor[12])

{

    int i;

    for(i = 0; i < sizeof vendors / sizeof(vendors[0]); ++i)

        if (memcmp(cpuid_vendor, vendors[i].vendor_string, 12) == 0)

            return vendors[i].vendor_code;

    return X86_VENDOR_UNKNOWN;

}

void identify_cpu(struct cpuinfo *cpuinfo)

{

    struct cpuid cpuid[2];

    /* Skip EFLAGS.ID check. We will only get here if

       the kernel has created a perfctr state for us,

       and that will never happen on pre-CPUID CPUs. */

    get_cpuid(0, &cpuid[0]);

    /* Quirk for Intel A-step Pentium. */

    if ((cpuid[0].eax & 0xFFFFFF00) == 0x0500) {

	cpuinfo->vendor = X86_VENDOR_INTEL;

	cpuinfo->signature = cpuid[0].eax;

	cpuinfo->features = 0x1BF; /* CX8,MCE,MSR,TSC,PSE,DE,VME,FPU */

	return;

    }

    cpuinfo->vendor = check_vendor((const char*)&cpuid[0].ebx);

    if (cpuid[0].eax == 0) {

	cpuinfo->signature = 0;

	cpuinfo->features = 0;

    } else {

	get_cpuid(1, &cpuid[1]);

	cpuinfo->signature = cpuid[1].eax;

	cpuinfo->features = cpuid[1].edx;

    }

}