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1 | \r |
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2 | // This file is part of the PicoDrive Megadrive Emulator\r |
3 | \r |
c41b9b97 |
4 | // Copyright (c) 2011 FinalDave (emudave (at) gmail.com)\r |
5 | \r |
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6 | // This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r |
7 | // You can choose the license that has the most advantages for you.\r |
8 | \r |
9 | // SVN repository can be found at http://code.google.com/p/cyclone68000/\r |
10 | \r |
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11 | #include "PicoInt.h"\r |
12 | \r |
13 | #ifdef MSOUND\r |
14 | extern "C"\r |
15 | {\r |
16 | int YM2612UpdateReq(int) { return 0; }\r |
17 | void *errorlog=NULL;\r |
18 | }\r |
19 | #endif\r |
20 | \r |
21 | int PsndRate=0,PsndLen=0;\r |
22 | short *PsndOut=NULL;\r |
23 | \r |
24 | // An operator is a single sine wave generator\r |
25 | struct Operator\r |
26 | {\r |
27 | unsigned short angle; // 0-0xffff\r |
28 | unsigned short freq; // Converted frequency\r |
29 | unsigned char key;\r |
30 | unsigned char state; // 1=attack, 2=decay, 3=sustain, 4=release\r |
31 | int vol;\r |
32 | int delta; // Change in volume per sample\r |
33 | int limit; // Next volume limit\r |
34 | };\r |
35 | \r |
36 | struct Channel\r |
37 | {\r |
38 | struct Operator op[4]; // 4 operators for the channel\r |
39 | unsigned short note; // Written to 0xa4 and 0xa0\r |
40 | };\r |
41 | \r |
42 | static struct Channel Chan[8];\r |
43 | \r |
44 | unsigned char PicoSreg[0x200];\r |
45 | \r |
46 | static int WriteReg(int side,int a,int d)\r |
47 | {\r |
48 | struct Channel *pc=NULL;\r |
49 | \r |
50 | PicoSreg[(side<<8)|a]=(unsigned char)d;\r |
51 | \r |
52 | if (a==0x28)\r |
53 | {\r |
54 | pc=Chan+(d&7);\r |
55 | // Key On/Key Off\r |
56 | if (d&0xf0) pc->op[0].state=1; // Attack\r |
57 | else pc->op[0].state=4; // Release\r |
58 | \r |
59 | return 0;\r |
60 | }\r |
61 | \r |
62 | // Find channel:\r |
63 | pc=Chan+(a&3); if (side) pc+=4;\r |
64 | \r |
65 | if ((a&0xf0)==0xa0)\r |
66 | {\r |
67 | int n=0,f=0,mult=2455;\r |
68 | \r |
69 | if (PsndRate>0) mult=44100*2455/PsndRate;\r |
70 | \r |
71 | if (a&4) pc->note =(unsigned short)(d<<8);\r |
72 | else pc->note|=d;\r |
73 | \r |
74 | // Convert to an actual frequency:\r |
75 | n=pc->note; f=(n&0x7ff)<<((n>>11)&7);\r |
76 | \r |
77 | pc->op[0].freq=(unsigned short)((f*mult)>>16);\r |
78 | return 0;\r |
79 | }\r |
80 | \r |
81 | return 0;\r |
82 | }\r |
83 | \r |
84 | int PsndReset()\r |
85 | {\r |
86 | int i=0;\r |
87 | memset(&Chan,0,sizeof(Chan));\r |
88 | memset(PicoSreg,0,sizeof(PicoSreg));\r |
89 | \r |
90 | // Change Sine wave into a square wave\r |
91 | for (i=0x00; i<0x080; i++) Sine[i]= 0x2000;\r |
92 | for (i=0x80; i<0x100; i++) Sine[i]=-0x2000;\r |
93 | \r |
94 | return 0;\r |
95 | }\r |
96 | \r |
97 | int PsndFm(int a,int d)\r |
98 | {\r |
99 | int side=0;\r |
100 | \r |
101 | #ifdef MSOUND\r |
102 | YM2612Write(0,a&3,(unsigned char)d);\r |
103 | #endif\r |
104 | \r |
105 | a&=3; side=a>>1; // Which side: channels 0-2 or 3-5\r |
106 | \r |
107 | if (a&1) WriteReg(side,Pico.s.fmsel[side],d); // Write register\r |
108 | else Pico.s.fmsel[side]=(unsigned char)d; // Select register\r |
109 | \r |
110 | return 0;\r |
111 | }\r |
112 | \r |
113 | static void BlankSound(short *dest,int len)\r |
114 | {\r |
115 | short *end=NULL;\r |
116 | \r |
117 | end=dest+(len<<1);\r |
118 | \r |
119 | // Init sound to silence:\r |
120 | do { *dest=0; dest++; } while (dest<end);\r |
121 | }\r |
122 | \r |
123 | // Add to output and clip:\r |
124 | static inline void AddClip(short *targ,int d)\r |
125 | {\r |
126 | int total=*targ+d;\r |
127 | if ((total+0x8000)&0xffff0000)\r |
128 | {\r |
129 | if (total>0) total=0x7fff; else total=-0x8000;\r |
130 | }\r |
131 | *targ=(short)total;\r |
132 | }\r |
133 | \r |
134 | static void OpNewState(int c)\r |
135 | {\r |
136 | struct Operator *op=Chan[c].op;\r |
137 | int off=0;\r |
138 | \r |
139 | off=((c&4)<<6)|(c&3);\r |
140 | \r |
141 | switch (op->state)\r |
142 | {\r |
143 | case 1:\r |
144 | {\r |
145 | // Attack:\r |
146 | int ar=PicoSreg[0x50|off];\r |
147 | ar&=0x1f; if (ar) ar+=0x10;\r |
148 | op->delta=ar<<7; op->limit=0x1000000; break;\r |
149 | }\r |
150 | case 2:\r |
151 | {\r |
152 | // Decay:\r |
153 | int d1r=PicoSreg[0x60|off];\r |
154 | d1r&=0x1f; if (d1r) d1r+=0x10;\r |
155 | op->delta=-(d1r<<5); op->limit=0;\r |
156 | }\r |
157 | break;\r |
158 | case 3:\r |
159 | {\r |
160 | // Sustain:\r |
161 | int d2r=0,rr=0;\r |
162 | \r |
163 | d2r=PicoSreg[0x70|off];\r |
164 | d2r&=0x1f; if (d2r) d2r+=0x10;\r |
165 | rr =PicoSreg[0x80|off];\r |
166 | rr>>=4;\r |
167 | \r |
168 | op->delta=-(d2r<<5); op->limit=rr<<20;\r |
169 | }\r |
170 | break;\r |
171 | case 4:\r |
172 | // Release:\r |
173 | int rr=PicoSreg[0x80|off];\r |
174 | rr&=0x0f; rr<<=1; rr+=0x10;\r |
175 | op->delta=-(rr<<5); op->limit=0;\r |
176 | break;\r |
177 | }\r |
178 | }\r |
179 | \r |
180 | // Merely adding this code in seems to bugger up the N-Gage???\r |
181 | static void UpdateOp(int c)\r |
182 | {\r |
183 | struct Operator *op=Chan[c].op;\r |
184 | \r |
185 | op->angle=(unsigned short)(op->angle+op->freq);\r |
186 | op->vol+=op->delta;\r |
187 | \r |
188 | switch (op->state)\r |
189 | {\r |
190 | case 1:\r |
191 | if (op->vol>=op->limit) { op->vol=op->limit; op->state++; OpNewState(c); }\r |
192 | break;\r |
193 | case 2: case 3: // Decay/Sustain\r |
194 | if (op->vol< op->limit) { op->vol=op->limit; op->state++; OpNewState(c); }\r |
195 | break;\r |
196 | case 4:\r |
197 | if (op->vol< op->limit) { op->vol=op->limit; }\r |
198 | break;\r |
199 | }\r |
200 | }\r |
201 | \r |
202 | static void AddChannel(int c,short *dest,int len)\r |
203 | {\r |
204 | struct Channel *pc=Chan+c;\r |
205 | struct Operator *op=pc->op;\r |
206 | short *end=NULL;\r |
207 | \r |
208 | // Work out volume delta for this operator:\r |
209 | OpNewState(c);\r |
210 | \r |
211 | end=dest+len;\r |
212 | do\r |
213 | {\r |
214 | int d=0;\r |
215 | d=Sine[(op->angle>>8)&0xff]>>2;\r |
216 | \r |
217 | d*=(op->vol>>8); d>>=16;\r |
218 | \r |
219 | // Add to output:\r |
220 | AddClip(dest,d);\r |
221 | UpdateOp(c);\r |
222 | \r |
223 | dest++;\r |
224 | }\r |
225 | while (dest<end);\r |
226 | }\r |
227 | \r |
228 | int PsndRender()\r |
229 | {\r |
230 | int i=0;\r |
231 | \r |
232 | if (PsndOut==NULL) return 1; // Not rendering sound\r |
233 | \r |
234 | #ifdef MSOUND\r |
235 | if (PicoOpt&1)\r |
236 | {\r |
237 | short *wave[2]={NULL,NULL};\r |
238 | wave[0]=PsndOut;\r |
239 | wave[1]=PsndOut+PsndLen;\r |
240 | YM2612UpdateOne(0,wave,PsndLen);\r |
241 | }\r |
242 | #endif\r |
243 | \r |
244 | if ((PicoOpt&1)==0)\r |
245 | {\r |
246 | BlankSound(PsndOut,PsndLen);\r |
247 | for (i=0;i<7;i++)\r |
248 | {\r |
249 | if (i!=3) AddChannel(i,PsndOut,PsndLen);\r |
250 | }\r |
251 | }\r |
252 | \r |
253 | return 0;\r |
254 | }\r |