stella/src/emucore/CartMDM.cxx

138 lines
4.2 KiB
C++

//============================================================================
//
// 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) 1995-2020 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.
//============================================================================
#include "System.hxx"
#include "CartMDM.hxx"
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
CartridgeMDM::CartridgeMDM(const ByteBuffer& image, size_t size,
const string& md5, const Settings& settings,
size_t bsSize)
: CartridgeEnhanced(image, size, md5, settings,
bsSize == 0 ? BSPF::nextPowerOfTwo(size) : bsSize)
{
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void CartridgeMDM::install(System& system)
{
CartridgeEnhanced::install(system);
// Get the page accessing methods for the hot spots since they overlap
// areas within the TIA we'll need to forward requests to the TIA
myHotSpotPageAccess[0] = mySystem->getPageAccess(0x0800);
myHotSpotPageAccess[1] = mySystem->getPageAccess(0x0900);
myHotSpotPageAccess[2] = mySystem->getPageAccess(0x0A00);
myHotSpotPageAccess[3] = mySystem->getPageAccess(0x0B00);
myHotSpotPageAccess[4] = mySystem->getPageAccess(0x0C00);
myHotSpotPageAccess[5] = mySystem->getPageAccess(0x0D00);
myHotSpotPageAccess[6] = mySystem->getPageAccess(0x0E00);
myHotSpotPageAccess[7] = mySystem->getPageAccess(0x0F00);
// Set the page accessing methods for the hot spots
System::PageAccess access(this, System::PageAccessType::READWRITE);
for(uInt16 addr = 0x0800; addr < 0x0BFF; addr += System::PAGE_SIZE)
mySystem->setPageAccess(addr, access);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeMDM::checkSwitchBank(uInt16 address, uInt8)
{
// Switch banks if necessary
if((address & 0x1C00) == 0x0800)
{
bank(address & 0x0FF);
return true;
}
return false;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
uInt8 CartridgeMDM::peek(uInt16 address)
{
// Because of the way we've set up accessing above, we can only
// get here when the addresses are from 0x800 - 0xBFF
checkSwitchBank(address);
int hotspot = ((address & 0x0F00) >> 8) - 8;
return myHotSpotPageAccess[hotspot].device->peek(address);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeMDM::poke(uInt16 address, uInt8 value)
{
// All possible addresses can appear here, but we only care
// about those below $1000
if(!(address & 0x1000))
{
checkSwitchBank(address);
int hotspot = ((address & 0x0F00) >> 8) - 8;
myHotSpotPageAccess[hotspot].device->poke(address, value);
}
return false;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeMDM::bank(uInt16 bank, uInt16)
{
if(bankLocked() || myBankingDisabled) return false;
CartridgeEnhanced::bank(bank);
// Accesses above bank 127 disable further bankswitching; we're only
// concerned with the lower byte
myBankingDisabled = myBankingDisabled || bank > 127;
return myBankChanged = true;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeMDM::save(Serializer& out) const
{
CartridgeEnhanced::save(out);
try
{
out.putBool(myBankingDisabled);
}
catch(...)
{
cerr << "ERROR: CartridgeMDM::save" << endl;
return false;
}
return true;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool CartridgeMDM::load(Serializer& in)
{
CartridgeEnhanced::load(in);
try
{
myBankingDisabled = in.getBool();
}
catch(...)
{
cerr << "ERROR: CartridgeMDM::load" << endl;
return false;
}
return true;
}