Mercurial > sdl-ios-xcode
annotate src/timer/macos/SDL_MPWtimer.c @ 968:4675910b0b7b
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
From: Hannu Savolainen
Subject: Re: SDL uses obsolete OSS features
I did some work on getting OSS to work better with SDL. There have been
some problems with select which should be fixed now.
I'm having some problems in understanding what is the purpose of the
DSP_WaitAudio() routine. I added a return to the very beginning of this
routine and commendted out the define for USE_BLOCKING_WRITES. At least
lbreakout2 seems to work as well as earlier. The latencies are the same.
An ordinary blocking write does exactly the same thing than DSP_WaitAudio
does. So I would recommend using the USE_BLOCKING_WRITES approach and
removing everything from the DSP_WaitAudio routine. Also enabling
USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because
you don't need to handle the partial writes (the do-while loop).
Attached is a patch against SDL-1.2.7. After these changes SDL will use
OSS as it's designed to be used (make it as simple as possible). This code
should work with all OSS implementations because it uses only the very
fundamental features that have been there since the jurassic times.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Fri, 12 Nov 2004 21:39:04 +0000 |
| parents | b8d311d90021 |
| children | c9b51268668f |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
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b8d311d90021
Updated copyright information for 2004 (Happy New Year!)
Sam Lantinga <slouken@libsdl.org>
parents:
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changeset
|
3 Copyright (C) 1997-2004 Sam Lantinga |
| 0 | 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 | |
|
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e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
parents:
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|
20 slouken@libsdl.org |
| 0 | 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 } |