/*
 * Adplug - Replayer for many OPL2/OPL3 audio file formats.
 * Copyright (C) 1999 - 2007 Simon Peter, <dn.tlp@gmx.net>, et al.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * realopl.cpp - Real hardware OPL, by Simon Peter <dn.tlp@gmx.net>
 *             - Linux support by Tomas Pollak <tomas@forkhq.com>
 */

#ifdef _MSC_VER     // Microsoft Visual C++
  #if (_MSC_VER >= 1900) // VS2015+
  // _inp and _outp are no longer part of the C runtime from VS2015/Win8.1
  int INP(int dummy) { return 0; }
  void OUTP(int dummy, int dummy2) { return; }
  #else // _MSC_VER < 1900
  # include <conio.h>
  # define INP  _inp
  # define OUTP _outp
  #endif // _MSC_VER < 1900
#elif defined(__WATCOMC__)  // Watcom C/C++ and OpenWatcom
  # include <conio.h>
  # define INP  inp
  # define OUTP outp
#elif defined(WIN32) && defined(__MSVCRT__) && defined(__MINGW32__) // MinGW32
  # define INP    inb
  # define OUTP(reg, val) outb(val, reg)
#elif defined(DJGPP)    // DJGPP
  # include <pc.h>
  # define INP  inportb
  # define OUTP outportb
#elif defined(linux) && defined(HAVE_SYS_IO_H)
  # include <sys/io.h>
  # define INP inb
  # define OUTP(reg,val) outb(val,reg)
#else // no support on other platforms
  # define INP(reg)   0
  # define OUTP(reg, val)
#endif

#include "realopl.h"

#define SHORTDELAY  6   // short delay in I/O port-reads after OPL hardware output
#define LONGDELAY   35  // long delay in I/O port-reads after OPL hardware output

const unsigned char CRealopl::op_table[9] =
{0x00, 0x01, 0x02, 0x08, 0x09, 0x0a, 0x10, 0x11, 0x12};

#if defined(WIN32) && defined(__MINGW32__)
static __inline unsigned char inb(unsigned short int port) {
  unsigned char _v;

  __asm__ __volatile__ ("inb %w1,%0":"=a" (_v):"Nd" (port));
  return _v;
}

static __inline void outb(unsigned char value, unsigned short int port) {
  __asm__ __volatile__ ("outb %b0,%w1": :"a" (value), "Nd" (port));
}
#endif

CRealopl::CRealopl(unsigned short initport)
  : adlport(initport), hardvol(0), bequiet(false), nowrite(false) {
  for (int i = 0; i < 22; i++) {
    hardvols[0][i][0] = 0;
    hardvols[0][i][1] = 0;
    hardvols[1][i][0] = 0;
    hardvols[1][i][1] = 0;
  }

  currType = TYPE_OPL3;
}

bool CRealopl::harddetect() {
  unsigned char   stat1, stat2, i;
  unsigned short  adp = (currChip == 0 ? adlport : adlport + 2);

  hardwrite(4, 0x60); hardwrite(4, 0x80);
  stat1 = INP(adp);
  hardwrite(2, 0xff); hardwrite(4, 0x21);

  for (i = 0; i < 80; i++) // wait for adlib
    INP(adp);

  stat2 = INP(adp);
  hardwrite(4, 0x60); hardwrite(4, 0x80);

  if (((stat1 & 0xe0) == 0) && ((stat2 & 0xe0) == 0xc0))
    return true;
  else
    return false;
}

bool CRealopl::detect() {
  unsigned char stat;

  setchip(0);

  if (harddetect()) {
    // is at least OPL2, check for OPL3
    currType = TYPE_OPL2;

    stat = INP(adlport);

    if (stat & 6) {
      // not OPL3, try dual-OPL2
      setchip(1);

      if (harddetect())
        currType = TYPE_DUAL_OPL2;

    } else {
      currType = TYPE_OPL3;
    }

    setchip(0);
    return true;

  } else {
    return false;
  }
}

void CRealopl::setvolume(int volume) {
  int i, j;

  hardvol = volume;

  for (j = 0; j < 2; j++)
    for (i = 0; i < 9; i++) {
      hardwrite(0x43 + op_table[i], ((hardvols[j][op_table[i] + 3][0] & 63) + volume) > 63 ? 63 : hardvols[j][op_table[i] + 3][0] + volume);

      if (hardvols[j][i][1] & 1) // modulator too?
        hardwrite(0x40 + op_table[i], ((hardvols[j][op_table[i]][0] & 63) + volume) > 63 ? 63 : hardvols[j][op_table[i]][0] + volume);
    }
}

void CRealopl::setquiet(bool quiet) {
  bequiet = quiet;

  if (quiet) {
    oldvol = hardvol;
    setvolume(63);

  } else
    setvolume(oldvol);
}

void CRealopl::hardwrite(int reg, int val) {
  int i;
  unsigned short adp = (currChip == 0 ? adlport : adlport + 2);

  if (nowrite)
    return;

#if defined(linux) && defined(HAVE_SYS_IO_H) // see whether we can access the port
  if (!gotperms) {
    if ((ioperm(adlport, 2, 1) != 0) || (ioperm(adlport + 2, 2, 1) != 0)) {
      return;
    }
    gotperms = true;
  }
#endif

  OUTP(adp, reg);   // set register

  for (i = 0; i < SHORTDELAY; i++) // wait for adlib
    INP(adp);

  OUTP(adp + 1, val); // set value

  for (i = 0; i < LONGDELAY; i++) // wait for adlib
    INP(adp);
}

void CRealopl::write(int reg, int val) {
  int i;

  if (nowrite)
    return;

  if (currType == TYPE_OPL2 && currChip > 0)
    return;

  if (bequiet && (reg >= 0xb0 && reg <= 0xb8)) // filter all key-on commands
    val &= ~32;

  if (reg >= 0x40 && reg <= 0x55)   // cache volumes
    hardvols[currChip][reg - 0x40][0] = val;

  if (reg >= 0xc0 && reg <= 0xc8)
    hardvols[currChip][reg - 0xc0][1] = val;

  if (hardvol)        // reduce volume
    for (i = 0; i < 9; i++) {
      if (reg == 0x43 + op_table[i])
        val = ((val & 63) + hardvol) > 63 ? 63 : val + hardvol;
      else if ((reg == 0x40 + op_table[i]) && (hardvols[currChip][i][1] & 1))
        val = ((val & 63) + hardvol) > 63 ? 63 : val + hardvol;
    }

  hardwrite(reg, val);
}

void CRealopl::init() {
  int i, j;

  for (j = 0; j < 2; j++) {
    setchip(j);

    // set all registers to zero
    for (i = 0; i < 256; i++) {
      write(i, 0);
    }

    // stop instruments
    for (i = 0; i < 9; i++) {
      hardwrite(0xb0 + i, 0);               // key off
      hardwrite(0x80 + op_table[i], 0xff);  // fastest release
    }

    hardwrite(0xbd, 0); // clear misc. register
  }

  setchip(0);
}
