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260 lines
6.8 KiB
C++
260 lines
6.8 KiB
C++
//
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// MSX.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 24/11/2017.
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// Copyright © 2017 Thomas Harte. All rights reserved.
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//
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#include "MSX.hpp"
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#include "../../Processors/Z80/Z80.hpp"
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#include "../../Components/1770/1770.hpp"
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#include "../../Components/9918/9918.hpp"
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#include "../../Components/8255/i8255.hpp"
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#include "../../Components/AY38910/AY38910.hpp"
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#include "../CRTMachine.hpp"
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#include "../ConfigurationTarget.hpp"
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namespace MSX {
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struct AYPortHandler: public GI::AY38910::PortHandler {
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void set_port_output(bool port_b, uint8_t value) {
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printf("AY port %c output: %02x\n", port_b ? 'b' : 'a', value);
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}
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uint8_t get_port_input(bool port_b) {
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printf("AY port %c input\n", port_b ? 'b' : 'a');
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return 0xff;
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}
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};
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class ConcreteMachine:
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public Machine,
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public CPU::Z80::BusHandler,
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public CRTMachine::Machine,
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public ConfigurationTarget::Machine {
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public:
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ConcreteMachine():
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z80_(*this),
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i8255_(i8255_port_handler_),
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i8255_port_handler_(*this) {
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ay_.set_port_handler(&ay_port_handler_);
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set_clock_rate(3579545);
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std::memset(unpopulated_, 0xff, sizeof(unpopulated_));
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}
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void setup_output(float aspect_ratio) override {
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vdp_.reset(new TI::TMS9918(TI::TMS9918::TMS9918A));
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}
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void close_output() override {
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}
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std::shared_ptr<Outputs::CRT::CRT> get_crt() override {
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return vdp_->get_crt();
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}
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std::shared_ptr<Outputs::Speaker> get_speaker() override {
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return nullptr;
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}
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void run_for(const Cycles cycles) override {
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z80_.run_for(cycles);
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}
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void configure_as_target(const StaticAnalyser::Target &target) override {
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}
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bool insert_media(const StaticAnalyser::Media &media) override {
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return true;
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}
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void page_memory(uint8_t value) {
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for(size_t c = 0; c < 4; ++c) {
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read_pointers_[c] = slot_read_pointers_[value & 3][c];
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write_pointers_[c] = slot_write_pointers_[value & 3][c];
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value >>= 2;
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}
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}
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HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
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if(time_until_interrupt_ > 0) {
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time_until_interrupt_ -= cycle.length;
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if(time_until_interrupt_ <= HalfCycles(0)) {
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z80_.set_interrupt_line(true, time_until_interrupt_);
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}
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}
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uint16_t address = cycle.address ? *cycle.address : 0x0000;
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switch(cycle.operation) {
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case CPU::Z80::PartialMachineCycle::ReadOpcode:
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case CPU::Z80::PartialMachineCycle::Read:
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*cycle.value = read_pointers_[address >> 14][address & 16383];
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break;
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case CPU::Z80::PartialMachineCycle::Write:
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write_pointers_[address >> 14][address & 16383] = *cycle.value;
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break;
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case CPU::Z80::PartialMachineCycle::Input:
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switch(address & 0xff) {
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case 0x98: case 0x99:
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vdp_->run_for(time_since_vdp_update_);
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time_since_vdp_update_ = 0;
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*cycle.value = vdp_->get_register(address);
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z80_.set_interrupt_line(vdp_->get_interrupt_line());
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time_until_interrupt_ = vdp_->get_time_until_interrupt();
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break;
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case 0xa2:
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ay_.set_control_lines(static_cast<GI::AY38910::ControlLines>(GI::AY38910::BDIR | GI::AY38910::BC1));
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ay_.set_data_input(*cycle.value);
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break;
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case 0xa8: case 0xa9:
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case 0xaa: case 0xab:
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*cycle.value = i8255_.get_register(address);
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break;
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}
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break;
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case CPU::Z80::PartialMachineCycle::Output:
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switch(address & 0xff) {
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case 0x98: case 0x99:
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vdp_->run_for(time_since_vdp_update_);
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time_since_vdp_update_ = 0;
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vdp_->set_register(address, *cycle.value);
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z80_.set_interrupt_line(vdp_->get_interrupt_line());
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time_until_interrupt_ = vdp_->get_time_until_interrupt();
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break;
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case 0xa0:
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ay_.set_control_lines(static_cast<GI::AY38910::ControlLines>(GI::AY38910::BDIR | GI::AY38910::BC2 | GI::AY38910::BC1));
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ay_.set_data_input(*cycle.value);
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break;
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case 0xa1:
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ay_.set_control_lines(static_cast<GI::AY38910::ControlLines>(GI::AY38910::BDIR | GI::AY38910::BC2));
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ay_.set_data_input(*cycle.value);
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break;
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case 0xa8: case 0xa9:
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case 0xaa: case 0xab:
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i8255_.set_register(address, *cycle.value);
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break;
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}
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break;
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default: break;
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}
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// Per the best information I currently have, the MSX inserts an extra cycle into each opcode read,
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// but otherwise runs without pause.
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HalfCycles addition((cycle.operation == CPU::Z80::PartialMachineCycle::ReadOpcode) ? 2 : 0);
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time_since_vdp_update_ += cycle.length + addition;
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return addition;
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}
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void flush() {
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vdp_->run_for(time_since_vdp_update_);
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time_since_vdp_update_ = 0;
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}
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// Obtains the system ROMs.
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bool set_rom_fetcher(const std::function<std::vector<std::unique_ptr<std::vector<uint8_t>>>(const std::string &machine, const std::vector<std::string> &names)> &roms_with_names) override {
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auto roms = roms_with_names(
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"MSX",
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{
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"basic.rom",
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"main_msx1.rom"
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});
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if(!roms[0] || !roms[1]) return false;
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basic_ = std::move(*roms[0]);
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basic_.resize(16384);
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main_ = std::move(*roms[1]);
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main_.resize(16384);
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for(size_t c = 0; c < 4; ++c) {
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for(size_t slot = 0; slot < 3; ++slot) {
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slot_read_pointers_[slot][c] = unpopulated_;
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slot_write_pointers_[slot][c] = scratch_;
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}
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slot_read_pointers_[3][c] =
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slot_write_pointers_[3][c] = &ram_[c * 16384];
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}
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slot_read_pointers_[0][0] = main_.data();
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slot_read_pointers_[0][1] = basic_.data();
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for(size_t c = 0; c < 4; ++c) {
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read_pointers_[c] = slot_read_pointers_[0][c];
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write_pointers_[c] = slot_write_pointers_[0][c];
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}
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return true;
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}
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private:
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class i8255PortHandler: public Intel::i8255::PortHandler {
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public:
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i8255PortHandler(ConcreteMachine &machine) : machine_(machine) {}
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void set_value(int port, uint8_t value) {
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switch(port) {
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case 0: machine_.page_memory(value); break;
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case 2:
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printf("?? Select keyboard row, etc: %02x\n", value);
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break;
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default: break;
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}
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}
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uint8_t get_value(int port) {
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if(port == 1) {
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printf("?? Read keyboard\n");
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} else printf("What what?\n");
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return 0xff;
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}
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private:
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ConcreteMachine &machine_;
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};
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CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
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std::unique_ptr<TI::TMS9918> vdp_;
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Intel::i8255::i8255<i8255PortHandler> i8255_;
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GI::AY38910::AY38910 ay_;
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i8255PortHandler i8255_port_handler_;
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AYPortHandler ay_port_handler_;
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uint8_t *read_pointers_[4];
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uint8_t *write_pointers_[4];
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uint8_t *slot_read_pointers_[4][4];
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uint8_t *slot_write_pointers_[4][4];
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uint8_t ram_[65536];
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uint8_t scratch_[16384];
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uint8_t unpopulated_[16384];
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std::vector<uint8_t> basic_, main_;
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HalfCycles time_since_vdp_update_;
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HalfCycles time_until_interrupt_;
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};
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}
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using namespace MSX;
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Machine *Machine::MSX() {
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return new ConcreteMachine;
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}
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Machine::~Machine() {}
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