mirror of https://github.com/stella-emu/stella.git
143 lines
3.8 KiB
C++
143 lines
3.8 KiB
C++
//============================================================================
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//
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// SSSS tt lll lll
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// SS SS tt ll ll
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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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//
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// Copyright (c) 1995-2016 by Bradford W. Mott, Stephen Anthony
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// and the Stella Team
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//
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// See the file "License.txt" for information on usage and redistribution of
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// this file, and for a DISCLAIMER OF ALL WARRANTIES.
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//
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// $Id$
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//============================================================================
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#include <cstring>
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#include "System.hxx"
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#include "Cart2K.hxx"
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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Cartridge2K::Cartridge2K(const uInt8* image, uInt32 size, const Settings& settings)
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: Cartridge(settings),
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myImage(nullptr)
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{
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// Size can be a maximum of 2K
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if(size > 2048) size = 2048;
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// Set image size to closest power-of-two for the given size
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mySize = 1;
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while(mySize < size)
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mySize <<= 1;
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// The smallest addressable area by Stella is 64 bytes
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// This should really be read from the System, but for now I'm going
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// to cheat a little and hard-code it to 64 (aka 2^6)
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if(mySize < 64)
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mySize = 64;
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// Initialize ROM with illegal 6502 opcode that causes a real 6502 to jam
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myImage = new uInt8[mySize];
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memset(myImage, 0x02, mySize);
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// Copy the ROM image into my buffer
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memcpy(myImage, image, size);
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createCodeAccessBase(mySize);
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// Set mask for accessing the image buffer
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// This is guaranteed to work, as mySize is a power of two
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myMask = mySize - 1;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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Cartridge2K::~Cartridge2K()
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{
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delete[] myImage;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void Cartridge2K::reset()
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{
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myBankChanged = true;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void Cartridge2K::install(System& system)
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{
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mySystem = &system;
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// Map ROM image into the system
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System::PageAccess access(this, System::PA_READ);
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for(uInt32 address = 0x1000; address < 0x2000; address += (1 << System::PAGE_SHIFT))
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{
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access.directPeekBase = &myImage[address & myMask];
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access.codeAccessBase = &myCodeAccessBase[address & myMask];
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mySystem->setPageAccess(address >> System::PAGE_SHIFT, access);
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}
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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uInt8 Cartridge2K::peek(uInt16 address)
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{
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return myImage[address & myMask];
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool Cartridge2K::poke(uInt16, uInt8)
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{
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// This is ROM so poking has no effect :-)
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return false;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool Cartridge2K::patch(uInt16 address, uInt8 value)
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{
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myImage[address & myMask] = value;
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return myBankChanged = true;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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const uInt8* Cartridge2K::getImage(int& size) const
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{
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size = mySize;
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return myImage;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool Cartridge2K::save(Serializer& out) const
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{
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try
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{
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out.putString(name());
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}
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catch(...)
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{
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cerr << "ERROR: Cartridge2K::save" << endl;
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return false;
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}
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return true;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool Cartridge2K::load(Serializer& in)
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{
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try
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{
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if(in.getString() != name())
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return false;
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}
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catch(...)
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{
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cerr << "ERROR: Cartridge2K::load" << endl;
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return false;
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}
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return true;
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}
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