67 lines
2.7 KiB
C
67 lines
2.7 KiB
C
/* $NetBSD: clockreg.h,v 1.5 1996/04/01 05:16:52 scottr Exp $ */
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/*-
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* Copyright (C) 1993 Allen K. Briggs, Chris P. Caputo,
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* Michael L. Finch, Bradley A. Grantham, and
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* Lawrence A. Kesteloot
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the Alice Group.
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* 4. The names of the Alice Group or any of its members may not be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE ALICE GROUP ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE ALICE GROUP BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/*
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* Clock defines and things.
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* MacII clock characteristics used.
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*/
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#define CLK_SPEED 0.0000012766 /* time to complete a clock (3 MHz) */
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/*
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* Calculate clocks needed to hit HZ ticks/sec.
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*
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* The VIA clock speed is 1.2766us, so the timer value needed is:
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*
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* 1 1,000,000us 1
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* CLK_INTERVAL = -------- * ----------- * ------
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* 1.2766us 1s HZ
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*
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* While it may be tempting to simplify the following further, we can run
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* into integer overflow problems. Also note: do *not* define HZ to be
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* less than 12; overflow will occur, yielding invalid results.
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*/
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#define CLK_INTERVAL ((int)((((100000000L / HZ) * 100) / 12766)))
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#define CLK_INTH ((CLK_INTERVAL >> 8) & 0xff) /* high byte */
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#define CLK_INTL (CLK_INTERVAL & 0xff) /* low byte */
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#if !defined(PRF_INTERVAL)
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#define PRF_INTERVAL CLK_INTERVAL
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#endif
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#define SECYR 31536000
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