stella/src/emucore/Cart3E.cxx

91 lines
2.7 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 "TIA.hxx"
#include "Cart3E.hxx"
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Cartridge3E::Cartridge3E(const ByteBuffer& image, size_t size,
const string& md5, const Settings& settings,
size_t bsSize)
: CartridgeEnhanced(image, size, md5, settings,
bsSize == 0 ? BSPF::nextMultipleOf(size, 2_KB) : bsSize)
{
myBankShift = BANK_SHIFT;
myRamSize = RAM_SIZE;
myRamBankCount = RAM_BANKS;
myRamWpHigh = RAM_HIGH_WP;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void Cartridge3E::install(System& system)
{
CartridgeEnhanced::install(system);
System::PageAccess access(this, System::PageAccessType::WRITE);
// The hotspots ($3E and $3F) are in TIA address space, so we claim it here
for(uInt16 addr = 0x00; addr < 0x40; addr += System::PAGE_SIZE)
mySystem->setPageAccess(addr, access);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool Cartridge3E::checkSwitchBank(uInt16 address, uInt8 value)
{
// Switch banks if necessary
if(address == 0x003F) {
// Switch ROM bank into segment 0
bank(value);
return true;
}
else if(address == 0x003E)
{
// Switch RAM bank into segment 0
bank(value + romBankCount());
return true;
}
return false;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
uInt8 Cartridge3E::peek(uInt16 address)
{
uInt16 peekAddress = address;
address &= ROM_MASK;
if(address < 0x0040) // TIA access
return mySystem->tia().peek(address);
return CartridgeEnhanced::peek(peekAddress);
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool Cartridge3E::poke(uInt16 address, uInt8 value)
{
uInt16 pokeAddress = address;
address &= ROM_MASK;
if(address < 0x0040) // TIA access
{
checkSwitchBank(address, value);
return mySystem->tia().poke(address, value);
}
return CartridgeEnhanced::poke(pokeAddress, value);
}