mirror of https://github.com/stella-emu/stella.git
176 lines
4.7 KiB
C++
176 lines
4.7 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) 1995-2010 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 <cassert>
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#include <cstring>
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#include "System.hxx"
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#include "CartFE.hxx"
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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CartridgeFE::CartridgeFE(const uInt8* image)
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: myLastAddress1(0),
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myLastAddress2(0),
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myLastAddressChanged(false)
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{
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// Copy the ROM image into my buffer
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memcpy(myImage, image, 8192);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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CartridgeFE::~CartridgeFE()
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{
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void CartridgeFE::reset()
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{
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void CartridgeFE::install(System& system)
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{
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mySystem = &system;
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uInt16 shift = mySystem->pageShift();
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uInt16 mask = mySystem->pageMask();
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// Make sure the system we're being installed in has a page size that'll work
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assert((0x1000 & mask) == 0);
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// Map all of the accesses to call peek and poke
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System::PageAccess access;
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access.directPeekBase = 0;
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access.directPokeBase = 0;
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access.device = this;
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access.type = System::PA_READ;
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for(uInt32 i = 0x1000; i < 0x2000; i += (1 << shift))
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mySystem->setPageAccess(i >> shift, access);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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uInt8 CartridgeFE::peek(uInt16 address)
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{
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// The bank is determined by A13 of the processor
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// We keep track of the two most recent accesses to determine which bank
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// we're in, and when the values actually changed
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myLastAddress2 = myLastAddress1;
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myLastAddress1 = address;
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myLastAddressChanged = true;
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return myImage[(address & 0x0FFF) + (((address & 0x2000) == 0) ? 4096 : 0)];
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool CartridgeFE::poke(uInt16, uInt8)
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{
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return false;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void CartridgeFE::bank(uInt16 b)
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{
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// Doesn't support bankswitching in the normal sense
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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uInt16 CartridgeFE::bank() const
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{
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// The current bank depends on the last address accessed
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return ((myLastAddress1 & 0x2000) == 0) ? 1 : 0;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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uInt16 CartridgeFE::bankCount() const
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{
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return 2;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool CartridgeFE::bankChanged()
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{
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if(myLastAddressChanged)
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{
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// A bankswitch occurs when the addresses transition from state to another
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bool a1 = ((myLastAddress1 & 0x2000) == 0),
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a2 = ((myLastAddress2 & 0x2000) == 0);
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myBankChanged = (a1 && !a2) || (a2 && !a1);
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myLastAddressChanged = false;
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}
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else
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{
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myBankChanged = false;
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}
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// In any event, let the base class know about it
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return Cartridge::bankChanged();
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool CartridgeFE::patch(uInt16 address, uInt8 value)
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{
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myImage[(address & 0x0FFF) + (((address & 0x2000) == 0) ? 4096 : 0)] = value;
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return myBankChanged = true;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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const uInt8* CartridgeFE::getImage(int& size) const
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{
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size = 8192;
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return myImage;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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bool CartridgeFE::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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out.putInt(myLastAddress1);
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out.putInt(myLastAddress2);
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}
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catch(const char* msg)
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{
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cerr << "ERROR: CartridgeFE::save" << endl << " " << msg << 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 CartridgeFE::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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myLastAddress1 = (uInt16)in.getInt();
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myLastAddress2 = (uInt16)in.getInt();
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}
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catch(const char* msg)
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{
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cerr << "ERROR: CartridgeF8SC::load" << endl << " " << msg << 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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