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//============================================================================
//
// 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) 1995-2007 by Bradford W. Mott and the Stella team
//
// See the file "license" for information on usage and redistribution of
// this file, and for a DISCLAIMER OF ALL WARRANTIES.
//
// $Id: CartE7.hxx,v 1.10 2007/01/14 16:17:53 stephena Exp $
//============================================================================
#ifndef CARTRIDGEE7_HXX
#define CARTRIDGEE7_HXX
class System;
class Serializer;
class Deserializer;
#include "m6502/src/bspf/src/bspf.hxx"
#include "Cart.hxx"
#include "Random.hxx"
/**
This is the cartridge class for M-Network bankswitched games.
In this bankswitching scheme the 2600's 4K cartridge address
space is broken into two 2K segments.
Kevin Horton describes E7 as follows:
Only M-Network used this scheme. This has to be the
most complex method used in any cart! :-) It allows
for the capability of 2K of RAM; although it doesn't
have to be used (in fact, only one cart used it).
There are now 8 2K banks, instead of 4. The last 2K
in the cart always points to the last 2K of the ROM
image, while the first 2K is selectable. You access
1FE0 to 1FE6 to select which 2K bank. Note that you
cannot select the last 2K of the ROM image into the
lower 2K of the cart! Accessing 1FE7 selects 1K of
RAM at 1000-17FF instead of ROM! The 2K of RAM is
broken up into two 1K sections. One 1K section is
mapped in at 1000-17FF if 1FE7 has been accessed.
1000-13FF is the write port, while 1400-17FF is the
read port. The second 1K of RAM appears at 1800-19FF.
1800-18FF is the write port while 1900-19FF is the
read port. You select which 256 byte block appears
here by accessing 1FF8 to 1FFB.
@author Bradford W. Mott
@version $Id: CartE7.hxx,v 1.10 2007/01/14 16:17:53 stephena Exp $
*/
class CartridgeE7 : public Cartridge
{
public:
/**
Create a new cartridge using the specified image
@param image Pointer to the ROM image
@param rng A random number generator used to populate the initial extra RAM
*/
CartridgeE7(const uInt8* image, Random& rng);
/**
Destructor
*/
virtual ~CartridgeE7();
public:
/**
Get a null terminated string which is the device's name (i.e. "M6532")
@return The name of the device
*/
virtual const char* name() const;
/**
Reset device to its power-on state
*/
virtual void reset();
/**
Install cartridge in the specified system. Invoked by the system
when the cartridge is attached to it.
@param system The system the device should install itself in
*/
virtual void install(System& system);
/**
Saves the current state of this device to the given Serializer.
@param out The serializer device to save to.
@return The result of the save. True on success, false on failure.
*/
virtual bool save(Serializer& out);
/**
Loads the current state of this device from the given Deserializer.
@param in The deserializer device to load from.
@return The result of the load. True on success, false on failure.
*/
virtual bool load(Deserializer& in);
/**
Install pages for the specified bank in the system.
@param bank The bank that should be installed in the system
*/
virtual void bank(uInt16 bank);
/**
Get the current bank.
@return The current bank, or -1 if bankswitching not supported
*/
virtual int bank();
/**
Query the number of banks supported by the cartridge.
*/
virtual int bankCount();
/**
Patch the cartridge ROM.
@param address The ROM address to patch
@param value The value to place into the address
@return Success or failure of the patch operation
*/
virtual bool patch(uInt16 address, uInt8 value);
/**
Access the internal ROM image for this cartridge.
@param size Set to the size of the internal ROM image data
@return A pointer to the internal ROM image data
*/
virtual uInt8* getImage(int& size);
public:
/**
Get the byte at the specified address.
@return The byte at the specified address
*/
virtual uInt8 peek(uInt16 address);
/**
Change the byte at the specified address to the given value
@param address The address where the value should be stored
@param value The value to be stored at the address
*/
virtual void poke(uInt16 address, uInt8 value);
private:
/**
Install pages for the specified 256 byte bank of RAM
@param bank The bank that should be installed in the system
*/
void bankRAM(uInt16 bank);
private:
// Indicates which slice is in the segment
uInt16 myCurrentSlice[2];
// Indicates which 256 byte bank of RAM is being used
uInt16 myCurrentRAM;
// The 16K ROM image of the cartridge
uInt8 myImage[16384];
// The 2048 bytes of RAM
uInt8 myRAM[2048];
};
#endif