bsnes/supergameboy/common/adaptivesleep.cpp

57 lines
2.2 KiB
C++
Executable File

/***************************************************************************
* Copyright (C) 2008 by Sindre Aamås *
* aamas@stud.ntnu.no *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License version 2 as *
* published by the Free Software Foundation. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License version 2 for more details. *
* *
* You should have received a copy of the GNU General Public License *
* version 2 along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#include "adaptivesleep.h"
usec_t AdaptiveSleep::sleepUntil(usec_t base, usec_t inc) {
usec_t now = getusecs();
usec_t diff = now - base;
if (diff >= inc)
return diff - inc;
diff = inc - diff;
if (diff > oversleep + oversleepVar) {
diff -= oversleep + oversleepVar;
usecsleep(diff);
const usec_t ideal = now + diff;
now = getusecs();
{
usec_t curOversleep = now - ideal;
if (negate(curOversleep) < curOversleep)
curOversleep = 0;
oversleepVar = (oversleepVar * 15 + (curOversleep < oversleep ? oversleep - curOversleep : curOversleep - oversleep)) >> 4;
oversleep = (oversleep * 15 + curOversleep) >> 4;
}
noSleep = 60;
} else if (--noSleep == 0) {
noSleep = 60;
oversleep = oversleepVar = 0;
}
while (now - base < inc)
now = getusecs();
return 0;
}