1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
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
|
/*
* AdPlug - Replayer for many OPL2/OPL3 audio file formats.
* Copyright (C) 1999 - 2005 Simon Peter <dn.tlp@gmx.net>, et al.
*
* 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.
*
* 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.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* emuopl.cpp - Emulated OPL, by Simon Peter <dn.tlp@gmx.net>
*/
#include "emuopl.h"
#define likely(x) __builtin_expect((x),1)
#define unlikely(x) __builtin_expect((x),0)
CEmuopl::CEmuopl(int rate, bool bit16, bool usestereo)
: use16bit(bit16), stereo(usestereo), mixbufSamples(0)
{
opl[0] = OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
opl[1] = OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
mixbuf0 = 0;
mixbuf1 = 0;
currType = TYPE_DUAL_OPL2;
init();
}
CEmuopl::~CEmuopl()
{
OPLDestroy(opl[0]); OPLDestroy(opl[1]);
delete [] mixbuf0;
delete [] mixbuf1;
}
void CEmuopl::update(short *buf, int samples)
{
int i;
//ensure that our mix buffers are adequately sized
if(unlikely (mixbufSamples < samples)) {
if (mixbuf0) {
delete[] mixbuf0;
mixbuf0 = 0;
}
if (mixbuf1) {
delete[] mixbuf1;
mixbuf1 = 0;
}
//*2 = make room for stereo, if we need it
mixbuf0 = new short[samples*2];
mixbuf1 = new short[samples*2];
}
mixbufSamples = samples;
//data should be rendered to outbuf
//tempbuf should be used as a temporary buffer
//if we are supposed to generate 16bit output,
//then outbuf may point directly to the actual waveform output "buf"
//if we are supposed to generate 8bit output,
//then outbuf cannot point to "buf" (because there will not be enough room)
//and so it must point to a mixbuf instead--
//it will be reduced to 8bit and put in "buf" later
short *outbuf;
if (likely (use16bit)) {
outbuf = buf;
}
else {
outbuf = mixbuf1;
}
//...there is a potentially confusing situation where mixbuf1 can be aliased.
//beware. it is a little loony.
//all of the following rendering code produces 16bit output
switch(currType) {
case TYPE_OPL2:
//for opl2 mode:
//render chip0 to the output buffer
YM3812UpdateOne(opl[0],outbuf,samples);
//if we are supposed to output stereo,
//then we need to dup the mono channel
if(unlikely (stereo)) {
for(i=samples-1;i>=0;i--) {
outbuf[i*2] = outbuf[i];
outbuf[i*2+1] = outbuf[i];
}
}
break;
case TYPE_OPL3: // unsupported
break;
case TYPE_DUAL_OPL2:
//for dual opl2 mode:
//render each chip to a different tempbuffer
YM3812UpdateOne(opl[0],mixbuf1,samples);
YM3812UpdateOne(opl[1],mixbuf0,samples);
//output stereo:
//then we need to interleave the two buffers
if(unlikely (stereo)){
//first, spread tempbuf's samples across left channel
for(i=0;i<samples;i++)
outbuf[i*2] = mixbuf1[i];
//next, insert the samples from tempbuf2 into right channel
for(i=0;i<samples;i++)
outbuf[i*2+1] = mixbuf0[i];
} else {
//output mono:
//then we need to mix the two buffers into buf
for(i=0;i<samples;i++) {
int sample = (int)mixbuf0[i] + (int)mixbuf1[i];
if (unlikely (sample > 32767)) {
sample = 32767;
}
else if (unlikely (sample < -32768)) {
sample = -32768;
}
outbuf[i] = (short)sample;
}
}
break;
}
//now reduce to 8bit if we need to
if(unlikely (!use16bit)) {
int smp = stereo ? samples*2 : samples;
for(i=0;i<smp;i++) {
((char *)buf)[i] = (outbuf[i] >> 8) ^ 0x80;
}
}
}
void CEmuopl::write(int reg, int val)
{
switch(currType){
case TYPE_DUAL_OPL2:
OPLWrite(opl[1], 0, reg);
OPLWrite(opl[1], 1, val);
case TYPE_OPL2:
OPLWrite(opl[0], 0, reg);
OPLWrite(opl[0], 1, val);
break;
case TYPE_OPL3: // unsupported
break;
}
}
void CEmuopl::init()
{
OPLResetChip(opl[0]); OPLResetChip(opl[1]);
currChip = 0;
}
void CEmuopl::settype(ChipType type)
{
currType = type;
}
|
