1//============================================================================
2//
3// SSSS tt lll lll
4// SS SS tt ll ll
5// SS tttttt eeee ll ll aaaa
6// SSSS tt ee ee ll ll aa
7// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
8// SS SS tt ee ll ll aa aa
9// SSSS ttt eeeee llll llll aaaaa
10//
11// Copyright (c) 1995-2019 by Bradford W. Mott, Stephen Anthony
12// and the Stella Team
13//
14// See the file "License.txt" for information on usage and redistribution of
15// this file, and for a DISCLAIMER OF ALL WARRANTIES.
16//============================================================================
17
18#include "System.hxx"
19#include "CartMDM.hxx"
20
21// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
22CartridgeMDM::CartridgeMDM(const ByteBuffer& image, size_t size,
23 const string& md5, const Settings& settings)
24 : Cartridge(settings, md5),
25 mySize(size),
26 myBankOffset(0),
27 myBankingDisabled(false)
28{
29 // Allocate array for the ROM image
30 myImage = make_unique<uInt8[]>(mySize);
31
32 // Copy the ROM image into my buffer
33 std::copy_n(image.get(), mySize, myImage.get());
34 createCodeAccessBase(mySize);
35}
36
37// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
38void CartridgeMDM::reset()
39{
40 initializeStartBank(0);
41
42 // Upon reset we switch to the startup bank
43 bank(startBank());
44}
45
46// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
47void CartridgeMDM::install(System& system)
48{
49 mySystem = &system;
50
51 // Get the page accessing methods for the hot spots since they overlap
52 // areas within the TIA we'll need to forward requests to the TIA
53 myHotSpotPageAccess[0] = mySystem->getPageAccess(0x0800);
54 myHotSpotPageAccess[1] = mySystem->getPageAccess(0x0900);
55 myHotSpotPageAccess[2] = mySystem->getPageAccess(0x0A00);
56 myHotSpotPageAccess[3] = mySystem->getPageAccess(0x0B00);
57 myHotSpotPageAccess[4] = mySystem->getPageAccess(0x0C00);
58 myHotSpotPageAccess[5] = mySystem->getPageAccess(0x0D00);
59 myHotSpotPageAccess[6] = mySystem->getPageAccess(0x0E00);
60 myHotSpotPageAccess[7] = mySystem->getPageAccess(0x0F00);
61
62 // Set the page accessing methods for the hot spots
63 System::PageAccess access(this, System::PageAccessType::READWRITE);
64 for(uInt16 addr = 0x0800; addr < 0x0BFF; addr += System::PAGE_SIZE)
65 mySystem->setPageAccess(addr, access);
66
67 // Install pages for bank 0
68 bank(startBank());
69}
70
71// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
72uInt8 CartridgeMDM::peek(uInt16 address)
73{
74 // Because of the way we've set up accessing above, we can only
75 // get here when the addresses are from 0x800 - 0xBFF
76 if((address & 0x1C00) == 0x0800)
77 bank(address & 0x0FF);
78
79 int hotspot = ((address & 0x0F00) >> 8) - 8;
80 return myHotSpotPageAccess[hotspot].device->peek(address);
81}
82
83// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
84bool CartridgeMDM::poke(uInt16 address, uInt8 value)
85{
86 // All possible addresses can appear here, but we only care
87 // about those below $1000
88 if(!(address & 0x1000))
89 {
90 if((address & 0x1C00) == 0x0800)
91 bank(address & 0x0FF);
92
93 int hotspot = ((address & 0x0F00) >> 8) - 8;
94 myHotSpotPageAccess[hotspot].device->poke(address, value);
95 }
96
97 return false;
98}
99
100// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
101bool CartridgeMDM::bank(uInt16 bank)
102{
103 if(bankLocked() || myBankingDisabled) return false;
104
105 // Remember what bank we're in
106 // Wrap around to a valid bank number if necessary
107 myBankOffset = (bank % bankCount()) << 12;
108
109 // Setup the page access methods for the current bank
110 System::PageAccess access(this, System::PageAccessType::READ);
111
112 // Map ROM image into the system
113 for(uInt16 addr = 0x1000; addr < 0x2000; addr += System::PAGE_SIZE)
114 {
115 access.directPeekBase = &myImage[myBankOffset + (addr & 0x0FFF)];
116 access.codeAccessBase = &myCodeAccessBase[myBankOffset + (addr & 0x0FFF)];
117 mySystem->setPageAccess(addr, access);
118 }
119
120 // Accesses above bank 127 disable further bankswitching; we're only
121 // concerned with the lower byte
122 myBankingDisabled = myBankingDisabled || bank > 127;
123 return myBankChanged = true;
124}
125
126// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
127uInt16 CartridgeMDM::getBank(uInt16) const
128{
129 return myBankOffset >> 12;
130}
131
132// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
133uInt16 CartridgeMDM::bankCount() const
134{
135 return uInt16(mySize >> 12);
136}
137
138// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
139bool CartridgeMDM::patch(uInt16 address, uInt8 value)
140{
141 myImage[myBankOffset + (address & 0x0FFF)] = value;
142 return myBankChanged = true;
143}
144
145// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
146const uInt8* CartridgeMDM::getImage(size_t& size) const
147{
148 size = mySize;
149 return myImage.get();
150}
151
152// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
153bool CartridgeMDM::save(Serializer& out) const
154{
155 try
156 {
157 out.putInt(myBankOffset);
158 }
159 catch(...)
160 {
161 cerr << "ERROR: CartridgeMDM::save" << endl;
162 return false;
163 }
164
165 return true;
166}
167
168// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
169bool CartridgeMDM::load(Serializer& in)
170{
171 try
172 {
173 myBankOffset = in.getInt();
174 }
175 catch(...)
176 {
177 cerr << "ERROR: CartridgeMDM::load" << endl;
178 return false;
179 }
180
181 // Remember what bank we were in
182 bank(myBankOffset >> 12);
183
184 return true;
185}
186