source: mainline/kernel/arch/ia32/include/cpuid.h@ 8ccd2ea

/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup ia32
 * @{
 */
/** @file
 */

#ifndef KERN_ia32_CPUID_H_
#define KERN_ia32_CPUID_H_

#include <arch/types.h>

typedef struct {
        uint32_t cpuid_eax;
        uint32_t cpuid_ebx;
        uint32_t cpuid_ecx;
        uint32_t cpuid_edx;
} __attribute__ ((packed)) cpu_info_t;

struct __cpuid_extended_feature_info {
        unsigned sse3 :  1;
        unsigned      : 31;
} __attribute__ ((packed));

typedef union cpuid_extended_feature_info {
        struct __cpuid_extended_feature_info bits;
        uint32_t word;
} cpuid_extended_feature_info;

struct __cpuid_feature_info {
        unsigned                        : 23;
        unsigned mmx  :  1;
        unsigned fxsr :  1;
        unsigned sse  :  1;
        unsigned sse2 :  1;
        unsigned      :  5;
} __attribute__ ((packed));

typedef union cpuid_feature_info {
        struct __cpuid_feature_info bits;
        uint32_t word;
} cpuid_feature_info;


static inline uint32_t has_cpuid(void)
{
        uint32_t val, ret;
        
        asm volatile (
                "pushf\n"               /* read flags */
                "popl %0\n"
                "movl %0, %1\n"
                
                "btcl $21, %1\n"        /* swap the ID bit */
                
                "pushl %1\n"            /* propagate the change into flags */
                "popf\n"
                "pushf\n"
                "popl %1\n"
                
                "andl $(1 << 21), %0\n" /* interrested only in ID bit */
                "andl $(1 << 21), %1\n"
                "xorl %1, %0\n"
                : "=r" (ret), "=r" (val)
        );
        
        return ret;
}

static inline void cpuid(uint32_t cmd, cpu_info_t *info)
{
        asm volatile (
                "cpuid\n"
                : "=a" (info->cpuid_eax), "=b" (info->cpuid_ebx), "=c" (info->cpuid_ecx), "=d" (info->cpuid_edx)
                : "a" (cmd)
        );
}

#endif

/** @}
 */