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comparison src/timer/macos/SDL_MPWtimer.c @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children e8157fcb3114
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1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id$";
26 #endif
27
28 #include <Types.h>
29 #include <Timer.h>
30 #include <OSUtils.h>
31 #include <Gestalt.h>
32 #include <Processes.h>
33
34 #include <LowMem.h>
35
36 #include "SDL_timer.h"
37 #include "SDL_timer_c.h"
38
39 #define MS_PER_TICK (1000/60) /* MacOS tick = 1/60 second */
40
41 /* Note: This is only a step above the original 1/60s implementation.
42 * For a good implementation, see FastTimes.[ch], by Matt Slot.
43 */
44 #define USE_MICROSECONDS
45 #define WideTo64bit(w) (*(UInt64 *) &(w))
46
47 UInt64 start;
48
49 void SDL_StartTicks(void)
50 {
51 #ifdef USE_MICROSECONDS
52 UnsignedWide now;
53
54 Microseconds(&now);
55 start = WideTo64bit(now);
56 #else
57 /* FIXME: Should we implement a wrapping algorithm, like Win32? */
58 #endif
59 }
60
61 Uint32 SDL_GetTicks(void)
62 {
63 #ifdef USE_MICROSECONDS
64 UnsignedWide now;
65
66 Microseconds(&now);
67 return (Uint32)((WideTo64bit(now)-start)/1000);
68 #else
69 return(LMGetTicks()*MS_PER_TICK);
70 #endif
71 }
72
73 void SDL_Delay(Uint32 ms)
74 {
75 #ifdef USE_MICROSECONDS
76 Uint32 end_ms;
77
78 end_ms = SDL_GetTicks() + ms;
79 do {
80 /* FIXME: Yield CPU? */ ;
81 } while ( SDL_GetTicks() < end_ms );
82 #else
83 UInt32 unused; /* MJS */
84 Delay(ms/MS_PER_TICK, &unused);
85 #endif
86 }
87
88
89 /* Data to handle a single periodic alarm */
90 typedef struct _ExtendedTimerRec
91 {
92 TMTask tmTask;
93 ProcessSerialNumber taskPSN;
94 } ExtendedTimerRec, *ExtendedTimerPtr;
95
96 static ExtendedTimerRec gExtendedTimerRec;
97
98
99 int SDL_SYS_TimerInit(void)
100 {
101 /* We don't need a setup? */
102 return(0);
103 }
104
105 void SDL_SYS_TimerQuit(void)
106 {
107 /* We don't need a cleanup? */
108 return;
109 }
110
111 /* Our Stub routine to set up and then call the real routine. */
112 pascal void TimerCallbackProc(TMTaskPtr tmTaskPtr)
113 {
114 Uint32 ms;
115
116 WakeUpProcess(&((ExtendedTimerPtr) tmTaskPtr)->taskPSN);
117
118 ms = SDL_alarm_callback(SDL_alarm_interval);
119 if ( ms ) {
120 SDL_alarm_interval = ROUND_RESOLUTION(ms);
121 PrimeTime((QElemPtr)&gExtendedTimerRec.tmTask,
122 SDL_alarm_interval);
123 } else {
124 SDL_alarm_interval = 0;
125 }
126 }
127
128 int SDL_SYS_StartTimer(void)
129 {
130 /*
131 * Configure the global structure that stores the timing information.
132 */
133 gExtendedTimerRec.tmTask.qLink = NULL;
134 gExtendedTimerRec.tmTask.qType = 0;
135 gExtendedTimerRec.tmTask.tmAddr = NewTimerUPP(TimerCallbackProc);
136 gExtendedTimerRec.tmTask.tmCount = 0;
137 gExtendedTimerRec.tmTask.tmWakeUp = 0;
138 gExtendedTimerRec.tmTask.tmReserved = 0;
139 GetCurrentProcess(&gExtendedTimerRec.taskPSN);
140
141 /* Install the task record */
142 InsXTime((QElemPtr)&gExtendedTimerRec.tmTask);
143
144 /* Go! */
145 PrimeTime((QElemPtr)&gExtendedTimerRec.tmTask, SDL_alarm_interval);
146 return(0);
147 }
148
149 void SDL_SYS_StopTimer(void)
150 {
151 RmvTime((QElemPtr)&gExtendedTimerRec.tmTask);
152 }