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cpu_counter.h revision 1.8 
      1 /*	$NetBSD: cpu_counter.h,v 1.8 2008/04/28 20:23:24 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Bill Sommerfeld.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _I386_CPU_COUNTER_H_
     33 #define _I386_CPU_COUNTER_H_
     34 
     35 /*
     36  * Machine-specific support for CPU counter.
     37  */
     38 
     39 #include <machine/cpu.h>
     40 #include <machine/cpufunc.h>
     41 #include <machine/specialreg.h>
     42 
     43 #ifdef _KERNEL
     44 
     45 #include <x86/cpu_counter.h>
     46 
     47 static __inline int
     48 cpu_hascounter(void)
     49 {
     50 
     51 	/*
     52 	 * Note that:
     53 	 * 1) Intel documentation is very specific that code *must* test
     54 	 * the CPU feature flag, even if you "know" that a particular
     55 	 * rev of the hardware supports it.
     56 	 * 2) We know that the TSC is busted on some Cyrix CPU in that if
     57 	 * you execute "hlt" when in powersave mode, TSC stops counting,
     58 	 * even though the CPU clock crystal is still ticking (it always has to).
     59 	 */
     60 	return (cpu_feature & CPUID_TSC) != 0;
     61 }
     62 
     63 #endif /* _KERNEL */
     64 
     65 #endif /* !_I386_CPU_COUNTER_H_ */
     66