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//============================================================================
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// SS tttttt eeee ll ll aaaa
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// SSSS tt ee ee ll ll aa
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// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
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// SS SS tt ee ll ll aa aa
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// SSSS ttt eeeee llll llll aaaaa
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// Copyright (c) 1995-1998 by Bradford W. Mott
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// See the file "license" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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// $Id: CartE7.hxx,v 1.2 1998/07/15 20:30:56 bwmott Exp $
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//============================================================================
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#ifndef CARTRIDGEE7_HXX
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#define CARTRIDGEE7_HXX
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This is the cartridge class for M-Network bankswitched games.
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In this bankswitching scheme the 2600's 4K cartridge address
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space is broken into two 2K segments.
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Kevin Horton describes E7 as follows:
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Only M-Network used this scheme. This has to be the
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most complex method used in any cart! :-) It allows
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for the capability of 2K of RAM; although it doesn't
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have to be used (in fact, only one cart used it).
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There are now 8 2K banks, instead of 4. The last 2K
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in the cart always points to the last 2K of the ROM
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image, while the first 2K is selectable. You access
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1FE0 to 1FE6 to select which 2K bank. Note that you
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cannot select the last 2K of the ROM image into the
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lower 2K of the cart! Accessing 1FE7 selects 1K of
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RAM at 1000-17FF instead of ROM! The 2K of RAM is
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broken up into two 1K sections. One 1K section is
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mapped in at 1000-17FF if 1FE7 has been accessed.
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1000-13FF is the write port, while 1400-17FF is the
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read port. The second 1K of RAM appears at 1800-19FF.
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1800-18FF is the write port while 1900-19FF is the
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read port. You select which 256 byte block appears
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here by accessing 1FF8 to 1FFB.
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@author Bradford W. Mott
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@version $Id: CartE7.hxx,v 1.2 1998/07/15 20:30:56 bwmott Exp $
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class CartridgeE7 : public Cartridge
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Create a new cartridge using the specified image
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@param image Pointer to the ROM image
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CartridgeE7(const uInt8* image);
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virtual ~CartridgeE7();
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Get a null terminated string which is the device's name (i.e. "M6532")
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@return The name of the device
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virtual const char* name() const;
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Reset device to its power-on state
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Install cartridge in the specified system. Invoked by the system
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when the cartridge is attached to it.
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@param system The system the device should install itself in
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virtual void install(System& system);
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Get the byte at the specified address.
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@return The byte at the specified address
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virtual uInt8 peek(uInt16 address);
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Change the byte at the specified address to the given value
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@param address The address where the value should be stored
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@param value The value to be stored at the address
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virtual void poke(uInt16 address, uInt8 value);
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Map the specfied bank into the first segment
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@param bank The bank that should be installed in the system
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void bank(uInt16 bank);
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Install pages for the specified 256 byte bank of RAM
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@param bank The bank that should be installed in the system
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void bankRAM(uInt16 bank);
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// Indicates which slice is in the segment
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uInt16 myCurrentSlice[2];
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// Indicates which 256 byte bank of RAM is being used
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// The 16K ROM image of the cartridge
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uInt8 myImage[16384];
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// The 2048 bytes of RAM
added
removed
src/emucore/CartE7.hxx
