mirror of
https://github.com/bsnes-emu/bsnes.git
synced 2025-02-22 06:02:28 +01:00
76a8ecd32a
byuu says: Changelog: - moved Thread, Scheduler, Cheat functionality into emulator/ for all cores - start of actual Mega Drive emulation (two 68K instructions) I'm going to be rather terse on MD emulation, as it's too early for any meaningful dialogue here.
80 lines
2.2 KiB
C++
80 lines
2.2 KiB
C++
//Memory
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auto Memory::size() const -> uint { return 0; }
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//StaticRAM
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StaticRAM::StaticRAM(uint size) : _size(size) { _data = new uint8[_size]; }
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StaticRAM::~StaticRAM() { delete[] _data; }
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auto StaticRAM::data() -> uint8* { return _data; }
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auto StaticRAM::size() const -> uint { return _size; }
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auto StaticRAM::read(uint24 addr, uint8) -> uint8 { return _data[addr]; }
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auto StaticRAM::write(uint24 addr, uint8 data) -> void { _data[addr] = data; }
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auto StaticRAM::operator[](uint24 addr) -> uint8& { return _data[addr]; }
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auto StaticRAM::operator[](uint24 addr) const -> const uint8& { return _data[addr]; }
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//MappedRAM
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auto MappedRAM::reset() -> void {
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delete[] _data;
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_data = nullptr;
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_size = 0;
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_writeProtect = false;
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}
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auto MappedRAM::allocate(uint size) -> void {
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reset();
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_data = new uint8[_size = size];
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memory::fill(_data, _size, 0xff);
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}
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auto MappedRAM::writeProtect(bool writeProtect) -> void { _writeProtect = writeProtect; }
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auto MappedRAM::data() -> uint8* { return _data; }
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auto MappedRAM::size() const -> uint { return _size; }
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auto MappedRAM::read(uint24 addr, uint8) -> uint8 { return _data[addr]; }
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auto MappedRAM::write(uint24 addr, uint8 data) -> void { if(!_writeProtect) _data[addr] = data; }
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auto MappedRAM::operator[](uint24 addr) const -> const uint8& { return _data[addr]; }
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//Bus
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auto Bus::mirror(uint addr, uint size) -> uint {
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if(size == 0) return 0;
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uint base = 0;
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uint mask = 1 << 23;
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while(addr >= size) {
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while(!(addr & mask)) mask >>= 1;
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addr -= mask;
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if(size > mask) {
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size -= mask;
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base += mask;
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}
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mask >>= 1;
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}
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return base + addr;
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}
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auto Bus::reduce(uint addr, uint mask) -> uint {
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while(mask) {
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uint bits = (mask & -mask) - 1;
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addr = ((addr >> 1) & ~bits) | (addr & bits);
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mask = (mask & (mask - 1)) >> 1;
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}
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return addr;
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}
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auto Bus::read(uint24 addr, uint8 data) -> uint8 {
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data = reader[lookup[addr]](target[addr], data);
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if(cheat) {
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if(!(addr & 0x40e000)) addr = 0x7e0000 | (addr & 0x1fff); //de-mirror WRAM
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if(auto result = cheat.find(addr, data)) return result();
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}
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return data;
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}
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auto Bus::write(uint24 addr, uint8 data) -> void {
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return writer[lookup[addr]](target[addr], data);
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}
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