SDL_systimer.c
2
3
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2006 Sam Lantinga
5
6
7
8
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
10
11
12
13
This library 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
Lesser General Public License for more details.
15
16
17
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19
20
Sam Lantinga
slouken@libsdl.org
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
*/
#include <Types.h>
#include <Timer.h>
#include <OSUtils.h>
#include <Gestalt.h>
#include <Processes.h>
#include <LowMem.h>
#include "SDL_timer.h"
#include "SDL_timer_c.h"
#include "FastTimes.h"
#define MS_PER_TICK (1000.0/60.0) /* MacOS tick = 1/60 second */
#define kTwoPower32 (4294967296.0) /* 2^32 */
static double start_tick;
static int is_fast_inited = 0;
void SDL_StartTicks(void)
{
if ( ! is_fast_inited ) // important to check or FastTime may hang machine!
SDL_SYS_TimerInit();
start_tick = FastMicroseconds();
}
Uint32 SDL_GetTicks(void)
{
if ( ! is_fast_inited )
SDL_SYS_TimerInit();
return FastMilliseconds();
}
void SDL_Delay(Uint32 ms)
{
Uint32 stop, now;
stop = SDL_GetTicks() + ms;
do {
SystemTask();
now = SDL_GetTicks();
} while ( stop > now );
}
/*
void SDL_StartTicks(void)
{
// FIXME: Should we implement a wrapping algorithm, like Win32?
}
Uint32 SDL_GetTicks(void)
{
UnsignedWide ms;
Microseconds (&ms);
return ( ms.lo / 1000 );
}
void SDL_Delay(Uint32 ms)
{
UnsignedWide microsecs;
UInt32 stop;
Microseconds (µsecs);
stop = microsecs.lo + (ms * 1000);
while ( stop > microsecs.lo ) {
SystemTask ();
Microseconds (µsecs);
}
}*/
/* Data to handle a single periodic alarm */
typedef struct _ExtendedTimerRec
{
TMTask tmTask;
ProcessSerialNumber taskPSN;
} ExtendedTimerRec, *ExtendedTimerPtr;
static ExtendedTimerRec gExtendedTimerRec;
int SDL_SYS_TimerInit(void)
{
FastInitialize ();
is_fast_inited = 1;
return(0);
}
void SDL_SYS_TimerQuit(void)
{
/* We don't need a cleanup? */
return;
}
/* Our Stub routine to set up and then call the real routine. */
pascal void TimerCallbackProc(TMTaskPtr tmTaskPtr)
{
Uint32 ms;
WakeUpProcess(&((ExtendedTimerPtr) tmTaskPtr)->taskPSN);
ms = SDL_alarm_callback(SDL_alarm_interval);
if ( ms ) {
SDL_alarm_interval = ROUND_RESOLUTION(ms);
PrimeTime((QElemPtr)&gExtendedTimerRec.tmTask,
SDL_alarm_interval);
} else {
SDL_alarm_interval = 0;
}
}
int SDL_SYS_StartTimer(void)
{
/*
* Configure the global structure that stores the timing information.
*/
gExtendedTimerRec.tmTask.qLink = NULL;
gExtendedTimerRec.tmTask.qType = 0;
gExtendedTimerRec.tmTask.tmAddr = NewTimerProc(TimerCallbackProc);
gExtendedTimerRec.tmTask.tmCount = 0;
gExtendedTimerRec.tmTask.tmWakeUp = 0;
gExtendedTimerRec.tmTask.tmReserved = 0;
GetCurrentProcess(&gExtendedTimerRec.taskPSN);
/* Install the task record */
InsXTime((QElemPtr)&gExtendedTimerRec.tmTask);
/* Go! */
PrimeTime((QElemPtr)&gExtendedTimerRec.tmTask, SDL_alarm_interval);
return(0);
}
void SDL_SYS_StopTimer(void)
{
RmvTime((QElemPtr)&gExtendedTimerRec.tmTask);
}