mirror of
https://github.com/TomHarte/CLK.git
synced 2024-12-11 15:49:38 +00:00
70 lines
1.7 KiB
C++
70 lines
1.7 KiB
C++
//
|
|
// CartridgeMNetwork.h
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 18/03/2017.
|
|
// Copyright 2017 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#ifndef Atari2600_CartridgeMNetwork_hpp
|
|
#define Atari2600_CartridgeMNetwork_hpp
|
|
|
|
#include "Cartridge.hpp"
|
|
|
|
namespace Atari2600 {
|
|
namespace Cartridge {
|
|
|
|
class MNetwork: public BusExtender {
|
|
public:
|
|
MNetwork(uint8_t *rom_base, std::size_t rom_size) :
|
|
BusExtender(rom_base, rom_size) {
|
|
rom_ptr_[0] = rom_base + rom_size_ - 4096;
|
|
rom_ptr_[1] = rom_ptr_[0] + 2048;
|
|
high_ram_ptr_ = high_ram_;
|
|
}
|
|
|
|
void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
|
|
address &= 0x1fff;
|
|
if(!(address & 0x1000)) return;
|
|
|
|
if(address >= 0x1fe0 && address <= 0x1fe6) {
|
|
rom_ptr_[0] = rom_base_ + (address - 0x1fe0) * 2048;
|
|
} else if(address == 0x1fe7) {
|
|
rom_ptr_[0] = nullptr;
|
|
} else if(address >= 0x1ff8 && address <= 0x1ffb) {
|
|
int offset = (address - 0x1ff8) * 256;
|
|
high_ram_ptr_ = &high_ram_[offset];
|
|
}
|
|
|
|
if(address & 0x800) {
|
|
if(address < 0x1900) {
|
|
high_ram_ptr_[address & 255] = *value;
|
|
} else if(address < 0x1a00) {
|
|
if(isReadOperation(operation)) *value = high_ram_ptr_[address & 255];
|
|
} else {
|
|
if(isReadOperation(operation)) *value = rom_ptr_[1][address & 2047];
|
|
}
|
|
} else {
|
|
if(rom_ptr_[0]) {
|
|
if(isReadOperation(operation)) *value = rom_ptr_[0][address & 2047];
|
|
} else {
|
|
if(address < 0x1400) {
|
|
low_ram_[address & 1023] = *value;
|
|
} else {
|
|
if(isReadOperation(operation)) *value = low_ram_[address & 1023];
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
private:
|
|
uint8_t *rom_ptr_[2];
|
|
uint8_t *high_ram_ptr_;
|
|
uint8_t low_ram_[1024], high_ram_[1024];
|
|
};
|
|
|
|
}
|
|
}
|
|
|
|
#endif /* Atari2600_CartridgeMNetwork_hpp */
|