/[svn]/linuxsampler/trunk/src/engines/common/Event.cpp
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Contents of /linuxsampler/trunk/src/engines/common/Event.cpp

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Revision 292 - (show annotations) (download)
Mon Oct 25 14:59:18 2004 UTC (19 years, 5 months ago) by schoenebeck
File size: 5000 byte(s)
encapsulated error message into quotation marks

1 /***************************************************************************
2 * *
3 * LinuxSampler - modular, streaming capable sampler *
4 * *
5 * Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6 * *
7 * This program is free software; you can redistribute it and/or modify *
8 * it under the terms of the GNU General Public License as published by *
9 * the Free Software Foundation; either version 2 of the License, or *
10 * (at your option) any later version. *
11 * *
12 * This program is distributed in the hope that it will be useful, *
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15 * GNU General Public License for more details. *
16 * *
17 * You should have received a copy of the GNU General Public License *
18 * along with this program; if not, write to the Free Software *
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20 * MA 02111-1307 USA *
21 ***************************************************************************/
22
23 #include "Event.h"
24
25 namespace LinuxSampler {
26
27 /**
28 * Create an EventGenerator.
29 *
30 * @param SampleRate - sample rate of the sampler engine's audio output
31 * signal (in Hz)
32 */
33 EventGenerator::EventGenerator(uint SampleRate) {
34 uiSampleRate = SampleRate;
35 uiSamplesProcessed = 0;
36 FragmentTime.end = CreateTimeStamp();
37 }
38
39 /**
40 * Updates the time stamps for the beginning and end of the current audio
41 * fragment. This is needed to be able to calculate the respective sample
42 * point later to which an event belongs to.
43 *
44 * @param SamplesToProcess - number of sample points to process in this
45 * audio fragment cycle
46 */
47 void EventGenerator::UpdateFragmentTime(uint SamplesToProcess) {
48 // update time stamp for this audio fragment cycle
49 FragmentTime.begin = FragmentTime.end;
50 FragmentTime.end = CreateTimeStamp();
51 // recalculate sample ratio for this audio fragment
52 time_stamp_t fragmentDuration = FragmentTime.end - FragmentTime.begin;
53 FragmentTime.sample_ratio = (float) uiSamplesProcessed / (float) fragmentDuration;
54 // store amount of samples to process for the next cycle
55 uiSamplesProcessed = SamplesToProcess;
56 }
57
58 /**
59 * Create a new event with the current time as time stamp.
60 */
61 Event EventGenerator::CreateEvent() {
62 return Event(this, CreateTimeStamp());
63 }
64
65 /**
66 * Creates a real time stamp for the current moment. Out of efficiency this
67 * is implemented in inline assembly for each CPU independently; we currently
68 * don't use a generic solution for CPUs that are not yet covered by the
69 * assembly code, instead an error message is prompted on compile time, forcing
70 * the user to contact us.
71 */
72 EventGenerator::time_stamp_t EventGenerator::CreateTimeStamp() {
73 #if defined(__i386__) || defined(__x86_64__)
74 uint64_t t;
75 __asm__ __volatile__ ("rdtsc" : "=A" (t));
76 return t >> 8;
77 #elif defined(__ia64__)
78 time_stamp_t t;
79 __asm__ __volatile__ ("mov %0=ar.itc" : "=r"(t));
80 return t;
81 #elif defined(__powerpc__)
82 time_stamp_t t;
83 __asm__ __volatile__ (
84 "98: mftb %0\n"
85 "99:\n"
86 ".section __ftr_fixup,\"a\"\n"
87 " .long %1\n"
88 " .long 0\n"
89 " .long 98b\n"
90 " .long 99b\n"
91 ".previous"
92 : "=r" (t) : "i" (0x00000100)
93 );
94 return t;
95 #elif defined(__alpha__)
96 time_stamp_t t;
97 __asm__ __volatile__ ("rpcc %0" : "=r"(t));
98 return t;
99 #else // we don't want to use a slow generic solution
100 # error "Sorry, LinuxSampler lacks time stamp code for your system."
101 # error "Please report this error and the CPU you are using to the LinuxSampler developers mailing list!"
102 #endif
103 }
104
105 /**
106 * Will be called by an EventGenerator to create a new Event.
107 */
108 Event::Event(EventGenerator* pGenerator, time_stamp_t Time) {
109 pEventGenerator = pGenerator;
110 TimeStamp = Time;
111 iFragmentPos = -1;
112 }
113
114 } // namespace LinuxSampler

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