FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/initcpu.c

     /*
      * Copyright (c) KATO Takenori, 1997, 1998.
      * 
      * All rights reserved.  Unpublished rights reserved under the copyright
      * laws of Japan.
      * 
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer as
     *    the first lines of this file unmodified.
     * 2. 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.
     * 
     * 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.
     *
     * $FreeBSD: releng/5.1/sys/amd64/amd64/initcpu.c 114349 2003-05-01 01:05:25Z peter $
     */
    
    #include "opt_cpu.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/systm.h>
    #include <sys/sysctl.h>
    
    #include <machine/cputypes.h>
    #include <machine/md_var.h>
    #include <machine/specialreg.h>
    
    void initializecpu(void);
    
    static int      hw_instruction_sse;
    SYSCTL_INT(_hw, OID_AUTO, instruction_sse, CTLFLAG_RD,
        &hw_instruction_sse, 0, "SIMD/MMX2 instructions available in CPU");
    
    int     cpu;                    /* Are we 386, 386sx, 486, etc? */
    u_int   cpu_feature;            /* Feature flags */
    u_int   cpu_high;               /* Highest arg to CPUID */
    u_int   cpu_id;                 /* Stepping ID */
    u_int   cpu_procinfo;           /* HyperThreading Info / Brand Index / CLFUSH */
    char    cpu_vendor[20];         /* CPU Origin code */
    u_int   cpu_fxsr;               /* SSE enabled */
    
    /*
     * Initialize CR4 (Control register 4) to enable SSE instructions.
     */
    void
    enable_sse(void)
    {
            if ((cpu_feature & CPUID_XMM) && (cpu_feature & CPUID_FXSR)) {
                    load_cr4(rcr4() | CR4_FXSR | CR4_XMM);
                    cpu_fxsr = hw_instruction_sse = 1;
            }
    }
    
    void
    initializecpu(void)
    {
    
            switch (cpu) {
            default:
                    break;
            }
            enable_sse();
    }

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