furnace/src/engine/platform/fmshared_OPN.h

/**
 * Furnace Tracker - multi-system chiptune tracker
 * Copyright (C) 2021-2022 tildearrow and contributors
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _FMSHARED_OPN_H
#define _FMSHARED_OPN_H

#include "fmsharedbase.h"

#define CHIP_FREQBASE fmFreqBase
#define CHIP_DIVIDER fmDivBase

#define PLEASE_HELP_ME(_targetChan) \
  int boundaryBottom=parent->calcBaseFreq(chipClock,CHIP_FREQBASE,0,false); \
  int boundaryTop=parent->calcBaseFreq(chipClock,CHIP_FREQBASE,12,false); \
  int destFreq=NOTE_FNUM_BLOCK(c.value2,11); \
  int newFreq; \
  bool return2=false; \
  if (_targetChan.portaPause) { \
    if (parent->song.oldOctaveBoundary) { \
      if ((_targetChan.portaPauseFreq&0xf800)>(_targetChan.baseFreq&0xf800)) { \
        _targetChan.baseFreq=((_targetChan.baseFreq&0x7ff)>>1)|(_targetChan.portaPauseFreq&0xf800); \
      } else { \
        _targetChan.baseFreq=((_targetChan.baseFreq&0x7ff)<<1)|(_targetChan.portaPauseFreq&0xf800); \
      } \
      c.value*=2; \
    } else { \
      _targetChan.baseFreq=_targetChan.portaPauseFreq; \
    } \
  } \
  if (destFreq>_targetChan.baseFreq) { \
    newFreq=_targetChan.baseFreq+c.value; \
    if (newFreq>=destFreq) { \
      newFreq=destFreq; \
      return2=true; \
    } \
  } else { \
    newFreq=_targetChan.baseFreq-c.value; \
    if (newFreq<=destFreq) { \
      newFreq=destFreq; \
      return2=true; \
    } \
  } \
  /* check for octave boundary */ \
  /* what the heck! */ \
  if (!_targetChan.portaPause) { \
    if ((newFreq&0x7ff)>boundaryTop && (newFreq&0xf800)<0x3800) { \
      if (parent->song.fbPortaPause) { \
        _targetChan.portaPauseFreq=(boundaryBottom)|((newFreq+0x800)&0xf800); \
        _targetChan.portaPause=true; \
        break; \
      } else { \
        newFreq=((newFreq&0x7ff)>>1)|((newFreq+0x800)&0xf800); \
      } \
    } \
    if ((newFreq&0x7ff)<boundaryBottom && (newFreq&0xf800)>0) { \
      if (parent->song.fbPortaPause) { \
        _targetChan.portaPauseFreq=newFreq=(boundaryTop-1)|((newFreq-0x800)&0xf800); \
        _targetChan.portaPause=true; \
        break; \
      } else { \
        newFreq=((newFreq&0x7ff)<<1)|((newFreq-0x800)&0xf800); \
      } \
    } \
  } \
  _targetChan.portaPause=false; \
  _targetChan.freqChanged=true; \
  _targetChan.baseFreq=newFreq; \
  if (return2) { \
    _targetChan.inPorta=false; \
    return 2; \
  }

class DivPlatformOPNBase: public DivPlatformFMBase {
  protected:
    const unsigned char ADDR_MULT_DT=0x30;
    const unsigned char ADDR_TL=0x40;
    const unsigned char ADDR_RS_AR=0x50;
    const unsigned char ADDR_AM_DR=0x60;
    const unsigned char ADDR_DT2_D2R=0x70;
    const unsigned char ADDR_SL_RR=0x80;
    const unsigned char ADDR_SSG=0x90;
    const unsigned char ADDR_FREQ=0xa0;
    const unsigned char ADDR_FREQH=0xa4;
    const unsigned char ADDR_FB_ALG=0xb0;
    const unsigned char ADDR_LRAF=0xb4;

    const unsigned short opOffs[4]={
      0x00, 0x04, 0x08, 0x0c
    };

    const double fmFreqBase;
    const double fmDivBase;
    const unsigned char ayDiv;

    DivPlatformOPNBase(double f=9440540.0, double d=72, unsigned char a=32):
      DivPlatformFMBase(),
      fmFreqBase(f),
      fmDivBase(d),
      ayDiv(a) {}

};

#endif