dsp1emu.c

SFC游戏模拟器 snes9x 1.43 的原代码

//Copyright (C) 1997-2001 ZSNES Team ( [e-mail] / [e-mail] )
//
//This program is free software; you can redistribute it and/or
//modify it under the terms of the GNU General Public License
//as published by the Free Software Foundation; either
//version 2 of the License, or (at your option) any later
//version.
//
//This program 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 General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; if not, write to the Free Software
//Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

//#define __ZSNES__

#if (defined __ZSNES__ && __LINUX__)
#include "../gblhdr.h"
#else

#include <stdio.h>
#include <stdarg.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#endif
//#define DebugDSP1

// uncomment some lines to test
//#define printinfo
//#define debug06

#define __OPT__
#define __OPT06__

#ifdef DebugDSP1

FILE * LogFile = NULL;

void Log_Message (char *Message, ...)
{
	char Msg[400];
	va_list ap;

   va_start(ap,Message);
   vsprintf(Msg,Message,ap );
   va_end(ap);
	
   strcat(Msg,"\r\n\0");
   fwrite(Msg,strlen(Msg),1,LogFile);
   fflush (LogFile);
}

void Start_Log (void)
{
	char LogFileName[255];
//  [4/15/2001]	char *p;

   strcpy(LogFileName,"dsp1emu.log\0");
	
   LogFile = fopen(LogFileName,"wb");
}

void Stop_Log (void)
{
   if (LogFile)
   {
      fclose(LogFile);
      LogFile = NULL;
	}
}

#endif

const unsigned short DSP1ROM[1024] = {
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0001,	0x0002,	0x0004,	0x0008,	0x0010,	0x0020,	
	0x0040,	0x0080,	0x0100,	0x0200,	0x0400,	0x0800,	0x1000,	0x2000,	
	0x4000,	0x7fff,	0x4000,	0x2000,	0x1000,	0x0800,	0x0400,	0x0200,	
	0x0100,	0x0080,	0x0040,	0x0020,	0x0001,	0x0008,	0x0004,	0x0002,	
	0x0001,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	0x0000,	
	0x0000,	0x0000,	0x8000,	0xffe5,	0x0100,	0x7fff,	0x7f02,	0x7e08,	
	0x7d12,	0x7c1f,	0x7b30,	0x7a45,	0x795d,	0x7878,	0x7797,	0x76ba,	
	0x75df,	0x7507,	0x7433,	0x7361,	0x7293,	0x71c7,	0x70fe,	0x7038,	
	0x6f75,	0x6eb4,	0x6df6,	0x6d3a,	0x6c81,	0x6bca,	0x6b16,	0x6a64,	
	0x69b4,	0x6907,	0x685b,	0x67b2,	0x670b,	0x6666,	0x65c4,	0x6523,	
	0x6484,	0x63e7,	0x634c,	0x62b3,	0x621c,	0x6186,	0x60f2,	0x6060,	
	0x5fd0,	0x5f41,	0x5eb5,	0x5e29,	0x5d9f,	0x5d17,	0x5c91,	0x5c0c,	
	0x5b88,	0x5b06,	0x5a85,	0x5a06,	0x5988,	0x590b,	0x5890,	0x5816,	
	0x579d,	0x5726,	0x56b0,	0x563b,	0x55c8,	0x5555,	0x54e4,	0x5474,	
	0x5405,	0x5398,	0x532b,	0x52bf,	0x5255,	0x51ec,	0x5183,	0x511c,	
	0x50b6,	0x5050,	0x4fec,	0x4f89,	0x4f26,	0x4ec5,	0x4e64,	0x4e05,	
	0x4da6,	0x4d48,	0x4cec,	0x4c90,	0x4c34,	0x4bda,	0x4b81,	0x4b28,	
	0x4ad0,	0x4a79,	0x4a23,	0x49cd,	0x4979,	0x4925,	0x48d1,	0x487f,	
	0x482d,	0x47dc,	0x478c,	0x473c,	0x46ed,	0x469f,	0x4651,	0x4604,	
	0x45b8,	0x456c,	0x4521,	0x44d7,	0x448d,	0x4444,	0x43fc,	0x43b4,	
	0x436d,	0x4326,	0x42e0,	0x429a,	0x4255,	0x4211,	0x41cd,	0x4189,	
	0x4146,	0x4104,	0x40c2,	0x4081,	0x4040,	0x3fff,	0x41f7,	0x43e1,	
	0x45bd,	0x478d,	0x4951,	0x4b0b,	0x4cbb,	0x4e61,	0x4fff,	0x5194,	
	0x5322,	0x54a9,	0x5628,	0x57a2,	0x5914,	0x5a81,	0x5be9,	0x5d4a,	
	0x5ea7,	0x5fff,	0x6152,	0x62a0,	0x63ea,	0x6530,	0x6672,	0x67b0,	
	0x68ea,	0x6a20,	0x6b53,	0x6c83,	0x6daf,	0x6ed9,	0x6fff,	0x7122,	
	0x7242,	0x735f,	0x747a,	0x7592,	0x76a7,	0x77ba,	0x78cb,	0x79d9,	
	0x7ae5,	0x7bee,	0x7cf5,	0x7dfa,	0x7efe,	0x7fff,	0x0000,	0x0324,	
	0x0647,	0x096a,	0x0c8b,	0x0fab,	0x12c8,	0x15e2,	0x18f8,	0x1c0b,	
	0x1f19,	0x2223,	0x2528,	0x2826,	0x2b1f,	0x2e11,	0x30fb,	0x33de,	
	0x36ba,	0x398c,	0x3c56,	0x3f17,	0x41ce,	0x447a,	0x471c,	0x49b4,	
	0x4c3f,	0x4ebf,	0x5133,	0x539b,	0x55f5,	0x5842,	0x5a82,	0x5cb4,	
	0x5ed7,	0x60ec,	0x62f2,	0x64e8,	0x66cf,	0x68a6,	0x6a6d,	0x6c24,	
	0x6dca,	0x6f5f,	0x70e2,	0x7255,	0x73b5,	0x7504,	0x7641,	0x776c,	
	0x7884,	0x798a,	0x7a7d,	0x7b5d,	0x7c29,	0x7ce3,	0x7d8a,	0x7e1d,	
	0x7e9d,	0x7f09,	0x7f62,	0x7fa7,	0x7fd8,	0x7ff6,	0x7fff,	0x7ff6,	
	0x7fd8,	0x7fa7,	0x7f62,	0x7f09,	0x7e9d,	0x7e1d,	0x7d8a,	0x7ce3,	
	0x7c29,	0x7b5d,	0x7a7d,	0x798a,	0x7884,	0x776c,	0x7641,	0x7504,	
	0x73b5,	0x7255,	0x70e2,	0x6f5f,	0x6dca,	0x6c24,	0x6a6d,	0x68a6,	
	0x66cf,	0x64e8,	0x62f2,	0x60ec,	0x5ed7,	0x5cb4,	0x5a82,	0x5842,	
	0x55f5,	0x539b,	0x5133,	0x4ebf,	0x4c3f,	0x49b4,	0x471c,	0x447a,	
	0x41ce,	0x3f17,	0x3c56,	0x398c,	0x36ba,	0x33de,	0x30fb,	0x2e11,	
	0x2b1f,	0x2826,	0x2528,	0x2223,	0x1f19,	0x1c0b,	0x18f8,	0x15e2,	
	0x12c8,	0x0fab,	0x0c8b,	0x096a,	0x0647,	0x0324,	0x7fff,	0x7ff6,	
	0x7fd8,	0x7fa7,	0x7f62,	0x7f09,	0x7e9d,	0x7e1d,	0x7d8a,	0x7ce3,	
	0x7c29,	0x7b5d,	0x7a7d,	0x798a,	0x7884,	0x776c,	0x7641,	0x7504,	
	0x73b5,	0x7255,	0x70e2,	0x6f5f,	0x6dca,	0x6c24,	0x6a6d,	0x68a6,	
	0x66cf,	0x64e8,	0x62f2,	0x60ec,	0x5ed7,	0x5cb4,	0x5a82,	0x5842,	
	0x55f5,	0x539b,	0x5133,	0x4ebf,	0x4c3f,	0x49b4,	0x471c,	0x447a,	
	0x41ce,	0x3f17,	0x3c56,	0x398c,	0x36ba,	0x33de,	0x30fb,	0x2e11,	
	0x2b1f,	0x2826,	0x2528,	0x2223,	0x1f19,	0x1c0b,	0x18f8,	0x15e2,	
	0x12c8,	0x0fab,	0x0c8b,	0x096a,	0x0647,	0x0324,	0x0000,	0xfcdc,	
	0xf9b9,	0xf696,	0xf375,	0xf055,	0xed38,	0xea1e,	0xe708,	0xe3f5,	
	0xe0e7,	0xdddd,	0xdad8,	0xd7da,	0xd4e1,	0xd1ef,	0xcf05,	0xcc22,	
	0xc946,	0xc674,	0xc3aa,	0xc0e9,	0xbe32,	0xbb86,	0xb8e4,	0xb64c,	
	0xb3c1,	0xb141,	0xaecd,	0xac65,	0xaa0b,	0xa7be,	0xa57e,	0xa34c,	
	0xa129,	0x9f14,	0x9d0e,	0x9b18,	0x9931,	0x975a,	0x9593,	0x93dc,	
	0x9236,	0x90a1,	0x8f1e,	0x8dab,	0x8c4b,	0x8afc,	0x89bf,	0x8894,	
	0x877c,	0x8676,	0x8583,	0x84a3,	0x83d7,	0x831d,	0x8276,	0x81e3,	
	0x8163,	0x80f7,	0x809e,	0x8059,	0x8028,	0x800a,	0x6488,	0x0080,	
	0x03ff,	0x0116,	0x0002,	0x0080,	0x4000,	0x3fd7,	0x3faf,	0x3f86,	
	0x3f5d,	0x3f34,	0x3f0c,	0x3ee3,	0x3eba,	0x3e91,	0x3e68,	0x3e40,	
	0x3e17,	0x3dee,	0x3dc5,	0x3d9c,	0x3d74,	0x3d4b,	0x3d22,	0x3cf9,	
	0x3cd0,	0x3ca7,	0x3c7f,	0x3c56,	0x3c2d,	0x3c04,	0x3bdb,	0x3bb2,	
	0x3b89,	0x3b60,	0x3b37,	0x3b0e,	0x3ae5,	0x3abc,	0x3a93,	0x3a69,	
	0x3a40,	0x3a17,	0x39ee,	0x39c5,	0x399c,	0x3972,	0x3949,	0x3920,	
	0x38f6,	0x38cd,	0x38a4,	0x387a,	0x3851,	0x3827,	0x37fe,	0x37d4,	
	0x37aa,	0x3781,	0x3757,	0x372d,	0x3704,	0x36da,	0x36b0,	0x3686,	
	0x365c,	0x3632,	0x3609,	0x35df,	0x35b4,	0x358a,	0x3560,	0x3536,	
	0x350c,	0x34e1,	0x34b7,	0x348d,	0x3462,	0x3438,	0x340d,	0x33e3,	
	0x33b8,	0x338d,	0x3363,	0x3338,	0x330d,	0x32e2,	0x32b7,	0x328c,	
	0x3261,	0x3236,	0x320b,	0x31df,	0x31b4,	0x3188,	0x315d,	0x3131,	
	0x3106,	0x30da,	0x30ae,	0x3083,	0x3057,	0x302b,	0x2fff,	0x2fd2,	
	0x2fa6,	0x2f7a,	0x2f4d,	0x2f21,	0x2ef4,	0x2ec8,	0x2e9b,	0x2e6e,	
	0x2e41,	0x2e14,	0x2de7,	0x2dba,	0x2d8d,	0x2d60,	0x2d32,	0x2d05,	
	0x2cd7,	0x2ca9,	0x2c7b,	0x2c4d,	0x2c1f,	0x2bf1,	0x2bc3,	0x2b94,	
	0x2b66,	0x2b37,	0x2b09,	0x2ada,	0x2aab,	0x2a7c,	0x2a4c,	0x2a1d,	
	0x29ed,	0x29be,	0x298e,	0x295e,	0x292e,	0x28fe,	0x28ce,	0x289d,	
	0x286d,	0x283c,	0x280b,	0x27da,	0x27a9,	0x2777,	0x2746,	0x2714,	
	0x26e2,	0x26b0,	0x267e,	0x264c,	0x2619,	0x25e7,	0x25b4,	0x2581,	
	0x254d,	0x251a,	0x24e6,	0x24b2,	0x247e,	0x244a,	0x2415,	0x23e1,	
	0x23ac,	0x2376,	0x2341,	0x230b,	0x22d6,	0x229f,	0x2269,	0x2232,	
	0x21fc,	0x21c4,	0x218d,	0x2155,	0x211d,	0x20e5,	0x20ad,	0x2074,	
	0x203b,	0x2001,	0x1fc7,	0x1f8d,	0x1f53,	0x1f18,	0x1edd,	0x1ea1,	
	0x1e66,	0x1e29,	0x1ded,	0x1db0,	0x1d72,	0x1d35,	0x1cf6,	0x1cb8,	
	0x1c79,	0x1c39,	0x1bf9,	0x1bb8,	0x1b77,	0x1b36,	0x1af4,	0x1ab1,	
	0x1a6e,	0x1a2a,	0x19e6,	0x19a1,	0x195c,	0x1915,	0x18ce,	0x1887,	
	0x183f,	0x17f5,	0x17ac,	0x1761,	0x1715,	0x16c9,	0x167c,	0x162e,	
	0x15df,	0x158e,	0x153d,	0x14eb,	0x1497,	0x1442,	0x13ec,	0x1395,	
	0x133c,	0x12e2,	0x1286,	0x1228,	0x11c9,	0x1167,	0x1104,	0x109e,	
	0x1036,	0x0fcc,	0x0f5f,	0x0eef,	0x0e7b,	0x0e04,	0x0d89,	0x0d0a,	
	0x0c86,	0x0bfd,	0x0b6d,	0x0ad6,	0x0a36,	0x098d,	0x08d7,	0x0811,	
	0x0736,	0x063e,	0x0519,	0x039a,	0x0000,	0x7fff,	0x0100,	0x0080,	
	0x021d,	0x00c8,	0x00ce,	0x0048,	0x0a26,	0x277a,	0x00ce,	0x6488,	
	0x14ac,	0x0001,	0x00f9,	0x00fc,	0x00ff,	0x00fc,	0x00f9,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	
	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff,	0xffff};

/***************************************************************************\
*  Math tables                                                              *
\***************************************************************************/

#define INCR 2048
#define Angle(x) (((x)/(65536/INCR)) & (INCR-1))
#define Cos(x) ((double) CosTable2[x])
#define Sin(x) ((double) SinTable2[x])
#ifdef PI
#undef PI
#endif
#define PI 3.1415926535897932384626433832795
double CosTable2[INCR];
double SinTable2[INCR];


double Atan(double x)
{
	if ((x>=1) || (x<=1)) 
		return (x/(1+0.28*x*x));
	else
		return (PI/2 - Atan(1/x));
}

#ifdef __ZSNES__
/***************************************************************************\
*  C4 C code                                                                *
\***************************************************************************/

short C4WFXVal;
short C4WFYVal;
short C4WFZVal;
short C4WFX2Val;
short C4WFY2Val;
short C4WFDist;
short C4WFScale;
double tanval;
double c4x,c4y,c4z;
double c4x2,c4y2,c4z2;

void C4TransfWireFrame()
{
  c4x=(double)C4WFXVal;
  c4y=(double)C4WFYVal;
  c4z=(double)C4WFZVal-0x95;

  // Rotate X
  tanval=-(double)C4WFX2Val*PI*2/128;
  c4y2=c4y*cos(tanval)-c4z*sin(tanval);
  c4z2=c4y*sin(tanval)+c4z*cos(tanval);

  // Rotate Y
  tanval=-(double)C4WFY2Val*PI*2/128;
  c4x2=c4x*cos(tanval)+c4z2*sin(tanval);
  c4z=c4x*-sin(tanval)+c4z2*cos(tanval);

  // Rotate Z
  tanval=-(double)C4WFDist*PI*2/128;
  c4x=c4x2*cos(tanval)-c4y2*sin(tanval);
  c4y=c4x2*sin(tanval)+c4y2*cos(tanval);

  // Scale
  C4WFXVal=(short)(c4x*C4WFScale/(0x90*(c4z+0x95))*0x95);
  C4WFYVal=(short)(c4y*C4WFScale/(0x90*(c4z+0x95))*0x95);
}

void C4TransfWireFrame2()
{
  c4x=(double)C4WFXVal;
  c4y=(double)C4WFYVal;
  c4z=(double)C4WFZVal;

  // Rotate X
  tanval=-(double)C4WFX2Val*PI*2/128;
  c4y2=c4y*cos(tanval)-c4z*sin(tanval);
  c4z2=c4y*sin(tanval)+c4z*cos(tanval);

  // Rotate Y
  tanval=-(double)C4WFY2Val*PI*2/128;
  c4x2=c4x*cos(tanval)+c4z2*sin(tanval);
  c4z=c4x*-sin(tanval)+c4z2*cos(tanval);

  // Rotate Z
  tanval=-(double)C4WFDist*PI*2/128;
  c4x=c4x2*cos(tanval)-c4y2*sin(tanval);
  c4y=c4x2*sin(tanval)+c4y2*cos(tanval);

  // Scale
  C4WFXVal=(short)(c4x*C4WFScale/0x100);
  C4WFYVal=(short)(c4y*C4WFScale/0x100);
}

void C4CalcWireFrame()
{
  C4WFXVal=C4WFX2Val-C4WFXVal;
  C4WFYVal=C4WFY2Val-C4WFYVal;
  if (abs(C4WFXVal)>abs(C4WFYVal)){
    C4WFDist=abs(C4WFXVal)+1;
    C4WFYVal=(256*(long)C4WFYVal)/abs(C4WFXVal);
    if (C4WFXVal<0) C4WFXVal=-256;
    else C4WFXVal=256;
  }
  else
  if (C4WFYVal!=0) {
    C4WFDist=abs(C4WFYVal)+1;
    C4WFXVal=(256*(long)C4WFXVal)/abs(C4WFYVal);
    if (C4WFYVal<0) C4WFYVal=-256;
    else C4WFYVal=256;
  }
  else C4WFDist=0;
}

short C41FXVal;
short C41FYVal;
short C41FAngleRes;
short C41FDist;
short C41FDistVal;

void C4Op1F()
{
  if (C41FXVal == 0) {
    if (C41FYVal>0) C41FAngleRes=0x80;
      else C41FAngleRes=0x180;
  }
  else {
    tanval = ((double)C41FYVal)/((double)C41FXVal);
    C41FAngleRes=(short)(atan(tanval)/(PI*2)*512);
    C41FAngleRes=C41FAngleRes;
    if (C41FXVal<0) C41FAngleRes+=0x100;
    C41FAngleRes&=0x1FF;
  }
}

void C4Op15()
{
  tanval=sqrt(((double)C41FYVal)*((double)C41FYVal)+((double)C41FXVal)*
    ((double)C41FXVal));
  C41FDist=(short)tanval;
}

void C4Op0D()
{
  tanval=sqrt(((double)C41FYVal)*((double)C41FYVal)+((double)C41FXVal)*
    ((double)C41FXVal));
  tanval=(double)C41FDistVal/tanval;
  C41FYVal=(short)(((double)C41FYVal*tanval)*0.99);
  C41FXVal=(short)(((double)C41FXVal*tanval)*0.98);
}
#endif

/***************************************************************************\
*  DSP1 code                                                                *
\***************************************************************************/

void InitDSP(void)
{
#ifdef __OPT__
        unsigned int i;
	for (i=0; i<INCR; i++){
		CosTable2[i] = (cos((double)(2*PI*i/INCR)));
		SinTable2[i] = (sin((double)(2*PI*i/INCR)));
	}
#endif
#ifdef DebugDSP1
	Start_Log();
#endif
}


short Op00Multiplicand;
short Op00Multiplier;
short Op00Result;

void DSPOp00()
{
   Op00Result= Op00Multiplicand * Op00Multiplier >> 15;

   #ifdef DebugDSP1
      Log_Message("OP00 MULT %d*%d/32768=%d",Op00Multiplicand,Op00Multiplier,Op00Result);
   #endif
}

short Op20Multiplicand;
short Op20Multiplier;
short Op20Result;

void DSPOp20()
{
   Op20Result= Op20Multiplicand * Op20Multiplier >> 15;
   Op20Result++;

   #ifdef DebugDSP1
      Log_Message("OP20 MULT %d*%d/32768=%d",Op20Multiplicand,Op20Multiplier,Op20Result);
   #endif
}

signed short Op10Coefficient;
signed short Op10Exponent;
signed short Op10CoefficientR;
signed short Op10ExponentR;

void DSP1_Inverse(short Coefficient, short Exponent, short *iCoefficient, short *iExponent)
{
	// Step One: Division by Zero
	if (Coefficient == 0x0000)
	{
		*iCoefficient = 0x7fff;
		*iExponent = 0x002f;
	}
	else
	{
		short Sign = 1;

		// Step Two: Remove Sign
		if (Coefficient < 0)
		{		
			if (Coefficient < -32767) Coefficient = -32767;
			Coefficient = -Coefficient;
			Sign = -1;
		}
		
		// Step Three: Normalize
		while (Coefficient < 0x4000)
		{
			Coefficient <<= 1;
			Exponent--;
		}

		// Step Four: Special Case
		if (Coefficient == 0x4000)
			if (Sign == 1) *iCoefficient = 0x7fff;
			else  {
				*iCoefficient = -0x4000;
				Exponent--;
			}
		else {
			// Step Five: Initial Guess
			short i = DSP1ROM[((Coefficient - 0x4000) >> 7) + 0x0065];

			// Step Six: Iterate "estimated" Newton's Method
			i = (i + (-i * (Coefficient * i >> 15) >> 15)) << 1;
			i = (i + (-i * (Coefficient * i >> 15) >> 15)) << 1;

			*iCoefficient = i * Sign;
		}

		*iExponent = 1 - Exponent;
	}
}

void DSPOp10()
{
	DSP1_Inverse(Op10Coefficient, Op10Exponent, &Op10CoefficientR, &Op10ExponentR);
	#ifdef DebugDSP1
        Log_Message("OP10 INV %d*2^%d = %d*2^%d", Op10Coefficient, Op10Exponent, Op10CoefficientR, Op10ExponentR);
	#endif
}

short Op04Angle;