79 lines
2.4 KiB
C
Executable File
79 lines
2.4 KiB
C
Executable File
// Windows-specific high resolution timer
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// Copyright (c) 2003 Jan Wassenberg
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// Contact info:
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// Jan.Wassenberg@stud.uni-karlsruhe.de
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// http://www.stud.uni-karlsruhe.de/~urkt/
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#include "types.h"
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// possible high resolution timers, in order of preference.
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// see source for timer properties + problems.
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// used as index into hrt_overrides.
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enum HRTImpl
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{
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// CPU timestamp counter
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HRT_TSC,
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// Windows QueryPerformanceCounter
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HRT_QPC,
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// Windows timeGetTime
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HRT_TGT,
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// there will always be a valid timer in use.
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// this is only used with hrt_override_impl.
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HRT_NONE,
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HRT_NUM_IMPLS
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};
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// while we do our best to work around timer problems or avoid them if unsafe,
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// future requirements and problems may be different:
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// allow the user or app to override our decisions (via hrt_override_impl)
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enum HRTOverride
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{
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// allow use of this implementation if available,
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// and we can work around its problems
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HRT_DEFAULT,
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// override our 'safe to use' recommendation
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// set by hrt_override_impl (via command line arg or console function)
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HRT_DISABLE,
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HRT_FORCE
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};
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// return ticks since first call.
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extern i64 hrt_ticks();
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// return seconds since first call.
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extern double hrt_time();
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// return seconds between start and end timestamps (returned by hrt_ticks).
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// negative if end comes before start.
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extern double hrt_delta_s(i64 start, i64 end);
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// return current timer implementation and its nominal (rated) frequency.
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// nominal_freq is never 0.
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// implementation only changes after hrt_override_impl.
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extern void hrt_query_impl(HRTImpl& impl, i64& nominal_freq);
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// override our 'safe to use' decision.
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// resets (and chooses another, if applicable) implementation;
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// the timer may jump after doing so.
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// call with HRT_DEFAULT, HRT_NONE to re-evaluate implementation choice
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// after system info becomes available.
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extern int hrt_override_impl(HRTOverride ovr, HRTImpl impl);
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