67 lines
1.9 KiB
C++
67 lines
1.9 KiB
C++
/*
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* timer.cpp
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*
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* Copyright (C) 1999-2006 Matt Ownby
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*
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* This file is part of DAPHNE, a laserdisc arcade game emulator
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*
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* DAPHNE is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* DAPHNE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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// by Matt Ownby, 11 August 1999
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// Purpose: To provide a way for our emulator to track very precise time
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// Second purpose: To keep this source code portable
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#include "timer.h"
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// returns the elapsed time (in milliseconds) since the current
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// time and previous_time (which is also in milliseconds)
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unsigned int elapsed_ms_time(unsigned int previous_time)
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{
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return(GET_TICKS() - previous_time);
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}
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unsigned int GetTicksFunc()
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{
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return GET_TICKS();
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}
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#ifdef GP2X
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unsigned int g_uLastTicks = 0;
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unsigned int g_uExtraMs = 0;
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unsigned int GP2X_GetTicks(unsigned int uMiniTicks)
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{
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// gp2x's mini ticks can be converted to ms by dividing by 7372.8, but we used 7373 for speed
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const unsigned int DIVIDER = 7373;
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// # of milliseconds in one cycle before 32-bit timer wraps around
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const unsigned int CYCLE_MS = 0xFFFFFFFF / DIVIDER;
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unsigned int uTicks = uMiniTicks / DIVIDER;
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// has wraparound occurred?
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if (uMiniTicks < g_uLastTicks)
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{
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g_uExtraMs += CYCLE_MS; // add one cycle to the extra
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}
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g_uLastTicks = uTicks;
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uTicks += g_uExtraMs; // add whatever extra we've accumulated
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return uTicks;
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}
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#endif // GP2X
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