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/*
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* High-resolution timing routines (PIT reprogramming)
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*
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* This file is part of the Mateusz' DOS Routines (MDR): http://mdr.osdn.io
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* Published under the terms of the MIT License, as stated below.
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*
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* Copyright (C) 2014-2022 Mateusz Viste
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef MDR_TIMER_H
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#define MDR_TIMER_H
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/* reset the timer value, this can be used by the application to make sure
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* no timer wrap occurs during critical parts of the code flow */
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void timer_reset(void);
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/* This routine will stop the fast clock if it is going. It has void return
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* value so that it can be an exit procedure. */
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void timer_stop(void);
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/* This routine will start the fast clock rate by installing the
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* handle_clock routine as the interrupt service routine for the clock
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* interrupt and then setting the interrupt rate up to its higher speed
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* by programming the 8253 timer chip.
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* This routine does nothing if the clock rate is already set to
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* its higher rate, but then it returns -1 to indicate the error. */
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void timer_init(void);
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/* This routine will return the present value of the time, which is
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* read from the nowtime structure. Interrupts are disabled during this
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* time to prevent the clock from changing while it is being read. */
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void timer_read(unsigned long *res);
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#endif
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