| 1 | \r |
| 2 | // This file is part of the PicoDrive Megadrive Emulator\r |
| 3 | \r |
| 4 | // Copyright (c) 2011 FinalDave (emudave (at) gmail.com)\r |
| 5 | \r |
| 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 |
| 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 |