license info added to Pico directory

[cyclone68000.git] / Pico / Psnd.cpp

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// This file is part of the PicoDrive Megadrive Emulator\r
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// This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r
// You can choose the license that has the most advantages for you.\r
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// SVN repository can be found at http://code.google.com/p/cyclone68000/\r
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#include "PicoInt.h"\r
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#ifdef MSOUND\r
extern "C"\r
{\r
int YM2612UpdateReq(int) { return 0; }\r
void *errorlog=NULL;\r
}\r
#endif\r
\r
int PsndRate=0,PsndLen=0;\r
short *PsndOut=NULL;\r
\r
// An operator is a single sine wave generator\r
struct Operator\r
{\r
  unsigned short angle; // 0-0xffff\r
  unsigned short freq; // Converted frequency\r
  unsigned char key;\r
  unsigned char state; // 1=attack, 2=decay, 3=sustain, 4=release\r
  int vol;\r
  int delta; // Change in volume per sample\r
  int limit; // Next volume limit\r
};\r
\r
struct Channel\r
{\r
  struct Operator op[4]; // 4 operators for the channel\r
  unsigned short note; // Written to 0xa4 and 0xa0\r
};\r
\r
static struct Channel Chan[8];\r
\r
unsigned char PicoSreg[0x200];\r
\r
static int WriteReg(int side,int a,int d)\r
{\r
  struct Channel *pc=NULL;\r
\r
  PicoSreg[(side<<8)|a]=(unsigned char)d;\r
\r
  if (a==0x28)\r
  {\r
    pc=Chan+(d&7);\r
    // Key On/Key Off\r
    if (d&0xf0) pc->op[0].state=1; // Attack\r
    else        pc->op[0].state=4; // Release\r
\r
    return 0;\r
  }\r
\r
  // Find channel:\r
  pc=Chan+(a&3); if (side) pc+=4;\r
\r
  if ((a&0xf0)==0xa0)\r
  {\r
    int n=0,f=0,mult=2455;\r
\r
    if (PsndRate>0) mult=44100*2455/PsndRate;\r
\r
    if (a&4) pc->note =(unsigned short)(d<<8);\r
    else     pc->note|=d;\r
\r
    // Convert to an actual frequency:\r
    n=pc->note; f=(n&0x7ff)<<((n>>11)&7);\r
\r
    pc->op[0].freq=(unsigned short)((f*mult)>>16);\r
    return 0;\r
  }\r
\r
  return 0;\r
}\r
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int PsndReset()\r
{\r
  int i=0;\r
  memset(&Chan,0,sizeof(Chan));\r
  memset(PicoSreg,0,sizeof(PicoSreg));\r
\r
// Change Sine wave into a square wave\r
  for (i=0x00; i<0x080; i++) Sine[i]= 0x2000;\r
  for (i=0x80; i<0x100; i++) Sine[i]=-0x2000;\r
\r
  return 0;\r
}\r
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int PsndFm(int a,int d)\r
{\r
  int side=0;\r
\r
#ifdef MSOUND\r
  YM2612Write(0,a&3,(unsigned char)d);\r
#endif\r
\r
  a&=3; side=a>>1; // Which side: channels 0-2 or 3-5\r
\r
  if (a&1) WriteReg(side,Pico.s.fmsel[side],d); // Write register\r
  else     Pico.s.fmsel[side]=(unsigned char)d; // Select register\r
\r
  return 0;\r
}\r
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static void BlankSound(short *dest,int len)\r
{\r
  short *end=NULL;\r
\r
  end=dest+(len<<1);\r
\r
  // Init sound to silence:\r
  do { *dest=0; dest++; } while (dest<end);\r
}\r
\r
// Add to output and clip:\r
static inline void AddClip(short *targ,int d)\r
{\r
  int total=*targ+d;\r
  if ((total+0x8000)&0xffff0000)\r
  {\r
    if (total>0) total=0x7fff; else total=-0x8000;\r
  }\r
  *targ=(short)total;\r
}\r
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static void OpNewState(int c)\r
{\r
  struct Operator *op=Chan[c].op;\r
  int off=0;\r
\r
  off=((c&4)<<6)|(c&3);\r
\r
  switch (op->state)\r
  {\r
    case 1:\r
    {\r
      // Attack:\r
      int ar=PicoSreg[0x50|off];\r
      ar&=0x1f; if (ar) ar+=0x10;\r
      op->delta=ar<<7; op->limit=0x1000000; break;\r
    }\r
    case 2:\r
    {\r
      // Decay:\r
      int d1r=PicoSreg[0x60|off];\r
      d1r&=0x1f; if (d1r) d1r+=0x10;\r
      op->delta=-(d1r<<5); op->limit=0;\r
    }\r
    break;\r
    case 3:\r
    {\r
      // Sustain:\r
      int d2r=0,rr=0;\r
      \r
      d2r=PicoSreg[0x70|off];\r
      d2r&=0x1f; if (d2r) d2r+=0x10;\r
      rr =PicoSreg[0x80|off];\r
      rr>>=4;\r
\r
      op->delta=-(d2r<<5); op->limit=rr<<20;\r
    }\r
    break;\r
    case 4:\r
      // Release:\r
      int rr=PicoSreg[0x80|off];\r
      rr&=0x0f; rr<<=1; rr+=0x10;\r
      op->delta=-(rr<<5); op->limit=0;\r
    break;\r
  }\r
}\r
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// Merely adding this code in seems to bugger up the N-Gage???\r
static void UpdateOp(int c)\r
{\r
  struct Operator *op=Chan[c].op;\r
\r
  op->angle=(unsigned short)(op->angle+op->freq);\r
  op->vol+=op->delta;\r
\r
  switch (op->state)\r
  {\r
    case 1:\r
      if (op->vol>=op->limit) { op->vol=op->limit; op->state++; OpNewState(c); }\r
    break;\r
    case 2: case 3: // Decay/Sustain\r
      if (op->vol< op->limit) { op->vol=op->limit; op->state++; OpNewState(c); }\r
    break;\r
    case 4:\r
      if (op->vol< op->limit) { op->vol=op->limit; }\r
    break;\r
  }\r
}\r
\r
static void AddChannel(int c,short *dest,int len)\r
{\r
  struct Channel *pc=Chan+c;\r
  struct Operator *op=pc->op;\r
  short *end=NULL;\r
\r
  // Work out volume delta for this operator:\r
  OpNewState(c);\r
\r
  end=dest+len;\r
  do\r
  {\r
    int d=0;\r
    d=Sine[(op->angle>>8)&0xff]>>2;\r
\r
    d*=(op->vol>>8); d>>=16;\r
\r
    // Add to output:\r
    AddClip(dest,d);\r
    UpdateOp(c);\r
\r
    dest++;\r
  }\r
  while (dest<end);\r
}\r
\r
int PsndRender()\r
{\r
  int i=0;\r
\r
  if (PsndOut==NULL) return 1; // Not rendering sound\r
\r
#ifdef MSOUND\r
  if (PicoOpt&1)\r
  {\r
    short *wave[2]={NULL,NULL};\r
    wave[0]=PsndOut;\r
    wave[1]=PsndOut+PsndLen;\r
    YM2612UpdateOne(0,wave,PsndLen);\r
  }\r
#endif\r
\r
  if ((PicoOpt&1)==0)\r
  {\r
    BlankSound(PsndOut,PsndLen);\r
    for (i=0;i<7;i++)\r
    {\r
      if (i!=3) AddChannel(i,PsndOut,PsndLen);\r
    }\r
  }\r
\r
  return 0;\r
}\r