c62d2810 |
1 | /* FCE Ultra - NES/Famicom Emulator |
2 | * |
3 | * Copyright notice for this file: |
4 | * Copyright (C) 2002 Ben Parnell |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify |
7 | * it under the terms of the GNU General Public License as published by |
8 | * the Free Software Foundation; either version 2 of the License, or |
9 | * (at your option) any later version. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | * GNU General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public License |
17 | * along with this program; if not, write to the Free Software |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
19 | */ |
20 | |
21 | static uint64 tmethod,tfreq; |
22 | static uint64 desiredfps; |
23 | |
24 | static void RefreshThrottleFPS(void) |
25 | { |
26 | desiredfps=FCEUI_GetDesiredFPS()>>8; |
27 | } |
28 | |
29 | static uint64 GetCurTime(void) |
30 | { |
31 | if(tmethod) |
32 | { |
33 | uint64 tmp; |
34 | |
35 | /* Practically, LARGE_INTEGER and uint64 differ only by signness and name. */ |
36 | QueryPerformanceCounter((LARGE_INTEGER*)&tmp); |
37 | |
38 | return(tmp); |
39 | } |
40 | else |
41 | return((uint64)GetTickCount()); |
42 | |
43 | } |
44 | |
45 | static void InitSpeedThrottle(void) |
46 | { |
47 | tmethod=0; |
48 | if(QueryPerformanceFrequency((LARGE_INTEGER*)&tfreq)) |
49 | { |
50 | tmethod=1; |
51 | } |
52 | else |
53 | tfreq=1000; |
54 | tfreq<<=16; /* Adjustment for fps returned from FCEUI_GetDesiredFPS(). */ |
55 | } |
56 | |
57 | |
58 | static void SpeedThrottle(void) |
59 | { |
60 | static uint64 ttime,ltime; |
61 | |
62 | waiter: |
63 | |
64 | ttime=GetCurTime(); |
65 | |
66 | |
67 | if( (ttime-ltime) < (tfreq/desiredfps) ) |
68 | goto waiter; |
69 | if( (ttime-ltime) >= (tfreq*4/desiredfps)) |
70 | ltime=ttime; |
71 | else |
72 | ltime+=tfreq/desiredfps; |
73 | } |