stella/src/emucore/CartF8.cxx

//============================================================================
//
//   SSSS    tt          lll  lll       
//  SS  SS   tt           ll   ll        
//  SS     tttttt  eeee   ll   ll   aaaa 
//   SSSS    tt   ee  ee  ll   ll      aa
//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
//  SS  SS   tt   ee      ll   ll  aa  aa
//   SSSS     ttt  eeeee llll llll  aaaaa
//
// Copyright (c) 1995-2016 by Bradford W. Mott, Stephen Anthony
// and the Stella Team
//
// See the file "License.txt" for information on usage and redistribution of
// this file, and for a DISCLAIMER OF ALL WARRANTIES.
//
// $Id$
//============================================================================

#include <cstring>

#include "System.hxx"
#include "CartF8.hxx"

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
CartridgeF8::CartridgeF8(const uInt8* image, uInt32 size, const string& md5,
                         const Settings& settings)
  : Cartridge(settings),
    myCurrentBank(0)
{
  // Copy the ROM image into my buffer
  memcpy(myImage, image, BSPF_min(8192u, size));
  createCodeAccessBase(8192);

  // Normally bank 1 is the reset bank, unless we're dealing with ROMs
  // that have been incorrectly created with banks in the opposite order
  myStartBank =
    (md5 == "bc24440b59092559a1ec26055fd1270e" ||  // Private Eye [a]
     md5 == "75ea60884c05ba496473c23a58edf12f" ||  // 8-in-1 Yars Revenge
     md5 == "75ee371ccfc4f43e7d9b8f24e1266b55" ||  // Snow White
     md5 == "74c8a6f20f8adaa7e05183f796eda796" ||  // Tricade Demo
     md5 == "9905f9f4706223dadee84f6867ede8e3")    // Challenge
    ? 0 : 1;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void CartridgeF8::reset()
{
  // Upon reset we switch to the reset bank
  bank(myStartBank);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void CartridgeF8::install(System& system)
{
  mySystem = &system;

  // Install pages for the startup bank
  bank(myStartBank);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
uInt8 CartridgeF8::peek(uInt16 address)
{
  address &= 0x0FFF;

  // Switch banks if necessary
  switch(address)
  {
    case 0x0FF8:
      // Set the current bank to the lower 4k bank
      bank(0);
      break;

    case 0x0FF9:
      // Set the current bank to the upper 4k bank
      bank(1);
      break;

    default:
      break;
  }

  return myImage[(myCurrentBank << 12) + address];
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeF8::poke(uInt16 address, uInt8)
{
  address &= 0x0FFF;

  // Switch banks if necessary
  switch(address)
  {
    case 0x0FF8:
      // Set the current bank to the lower 4k bank
      bank(0);
      break;

    case 0x0FF9:
      // Set the current bank to the upper 4k bank
      bank(1);
      break;

    default:
      break;
  }
  return false;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeF8::bank(uInt16 bank)
{ 
  if(bankLocked()) return false;

  // Remember what bank we're in
  myCurrentBank = bank;
  uInt16 offset = myCurrentBank << 12;

  System::PageAccess access(this, System::PA_READ);

  // Set the page accessing methods for the hot spots
  for(uInt32 i = (0x1FF8 & ~System::PAGE_MASK); i < 0x2000;
      i += (1 << System::PAGE_SHIFT))
  {
    access.codeAccessBase = &myCodeAccessBase[offset + (i & 0x0FFF)];
    mySystem->setPageAccess(i >> System::PAGE_SHIFT, access);
  }

  // Setup the page access methods for the current bank
  for(uInt32 address = 0x1000; address < (0x1FF8U & ~System::PAGE_MASK);
      address += (1 << System::PAGE_SHIFT))
  {
    access.directPeekBase = &myImage[offset + (address & 0x0FFF)];
    access.codeAccessBase = &myCodeAccessBase[offset + (address & 0x0FFF)];
    mySystem->setPageAccess(address >> System::PAGE_SHIFT, access);
  }
  return myBankChanged = true;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
uInt16 CartridgeF8::getBank() const
{
  return myCurrentBank;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
uInt16 CartridgeF8::bankCount() const
{
  return 2;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeF8::patch(uInt16 address, uInt8 value)
{
  myImage[(myCurrentBank << 12) + (address & 0x0FFF)] = value;
  return myBankChanged = true;
} 

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
const uInt8* CartridgeF8::getImage(int& size) const
{
  size = 8192;
  return myImage;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeF8::save(Serializer& out) const
{
  try
  {
    out.putString(name());
    out.putShort(myCurrentBank);
  }
  catch(...)
  {
    cerr << "ERROR: CartridgeF8::save" << endl;
    return false;
  }

  return true;
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeF8::load(Serializer& in)
{
  try
  {
    if(in.getString() != name())
      return false;

    myCurrentBank = in.getShort();
  }
  catch(...)
  {
    cerr << "ERROR: CartridgeF8SC::load" << endl;
    return false;
  }

  // Remember what bank we were in
  bank(myCurrentBank);

  return true;
}