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a30eeaab6a
They can be optional, and chained together in AND or OR combinations. A central catalogue knows the definitions of all ROMs.
503 lines
16 KiB
C++
503 lines
16 KiB
C++
//
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// ZX8081.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 04/06/2017.
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// Copyright 2017 Thomas Harte. All rights reserved.
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//
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#include "ZX8081.hpp"
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#include "../../MachineTypes.hpp"
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#include "../../../Components/AY38910/AY38910.hpp"
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#include "../../../Processors/Z80/Z80.hpp"
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#include "../../../Storage/Tape/Tape.hpp"
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#include "../../../Storage/Tape/Parsers/ZX8081.hpp"
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#include "../../../ClockReceiver/ForceInline.hpp"
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#include "../../Utility/MemoryFuzzer.hpp"
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#include "../../Utility/Typer.hpp"
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#include "../../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
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#include "../../../Analyser/Static/ZX8081/Target.hpp"
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#include "../Keyboard/Keyboard.hpp"
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#include "Video.hpp"
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#include <cstdint>
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#include <cstring>
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#include <memory>
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#include <vector>
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namespace {
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// The clock rate is 3.25Mhz.
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constexpr unsigned int ZX8081ClockRate = 3250000;
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}
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// TODO:
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// Quiksilva sound support:
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// 7FFFh.W PSG index
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// 7FFEh.R/W PSG data
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namespace Sinclair {
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namespace ZX8081 {
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enum ROMType: uint8_t {
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ZX80 = 0, ZX81
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};
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using CharacterMapper = Sinclair::ZX::Keyboard::CharacterMapper;
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template<bool is_zx81> class ConcreteMachine:
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public MachineTypes::TimedMachine,
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public MachineTypes::ScanProducer,
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public MachineTypes::AudioProducer,
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public MachineTypes::MediaTarget,
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public MachineTypes::MappedKeyboardMachine,
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public Configurable::Device,
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public Utility::TypeRecipient<CharacterMapper>,
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public CPU::Z80::BusHandler,
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public Machine {
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public:
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ConcreteMachine(const Analyser::Static::ZX8081::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
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Utility::TypeRecipient<CharacterMapper>(keyboard_machine()),
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z80_(*this),
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keyboard_(keyboard_machine()),
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keyboard_mapper_(keyboard_machine()),
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tape_player_(ZX8081ClockRate),
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ay_(GI::AY38910::Personality::AY38910, audio_queue_),
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speaker_(ay_) {
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set_clock_rate(ZX8081ClockRate);
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speaker_.set_input_rate(float(ZX8081ClockRate) / 2.0f);
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const bool use_zx81_rom = target.is_ZX81 || target.ZX80_uses_ZX81_ROM;
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const ROM::Name rom_name = use_zx81_rom ? ROM::Name::ZX81 : ROM::Name::ZX80;
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const ROM::Request request(rom_name);
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auto roms = rom_fetcher(request);
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if(!request.validate(roms)) {
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throw ROMMachine::Error::MissingROMs;
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}
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rom_ = std::move(roms.find(rom_name)->second);
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rom_mask_ = uint16_t(rom_.size() - 1);
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switch(target.memory_model) {
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case Analyser::Static::ZX8081::Target::MemoryModel::Unexpanded:
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ram_.resize(1024);
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ram_base_ = 16384;
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ram_mask_ = 1023;
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break;
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case Analyser::Static::ZX8081::Target::MemoryModel::SixteenKB:
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ram_.resize(16384);
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ram_base_ = 16384;
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ram_mask_ = 16383;
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break;
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case Analyser::Static::ZX8081::Target::MemoryModel::SixtyFourKB:
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ram_.resize(65536);
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ram_base_ = 8192;
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ram_mask_ = 65535;
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break;
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}
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Memory::Fuzz(ram_);
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// Ensure valid initial key state.
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clear_all_keys();
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if(!target.loading_command.empty()) {
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type_string(target.loading_command);
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should_autorun_ = true;
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}
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insert_media(target.media);
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}
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~ConcreteMachine() {
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audio_queue_.flush();
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}
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forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
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const HalfCycles previous_counter = horizontal_counter_;
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horizontal_counter_ += cycle.length;
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time_since_ay_update_ += cycle.length;
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if(previous_counter < vsync_start_ && horizontal_counter_ >= vsync_start_) {
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video_.run_for(vsync_start_ - previous_counter);
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set_hsync(true);
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line_counter_ = (line_counter_ + 1) & 7;
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if(nmi_is_enabled_) {
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z80_.set_non_maskable_interrupt_line(true);
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}
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video_.run_for(horizontal_counter_ - vsync_start_);
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} else if(previous_counter < vsync_end_ && horizontal_counter_ >= vsync_end_) {
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video_.run_for(vsync_end_ - previous_counter);
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set_hsync(false);
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if(nmi_is_enabled_) {
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z80_.set_non_maskable_interrupt_line(false);
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z80_.set_wait_line(false);
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}
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video_.run_for(horizontal_counter_ - vsync_end_);
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} else {
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video_.run_for(cycle.length);
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}
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if constexpr (is_zx81) horizontal_counter_ %= HalfCycles(Cycles(207));
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if(!tape_advance_delay_) {
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tape_player_.run_for(cycle.length);
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} else {
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tape_advance_delay_ = std::max(tape_advance_delay_ - cycle.length, HalfCycles(0));
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}
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if(nmi_is_enabled_ && !z80_.get_halt_line() && z80_.get_non_maskable_interrupt_line()) {
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z80_.set_wait_line(true);
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}
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if(!cycle.is_terminal()) {
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return Cycles(0);
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}
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const uint16_t address = cycle.address ? *cycle.address : 0;
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bool is_opcode_read = false;
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switch(cycle.operation) {
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case CPU::Z80::PartialMachineCycle::Output:
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if(!nmi_is_enabled_) {
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line_counter_ = 0;
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set_vsync(false);
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}
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if(!(address & 2)) nmi_is_enabled_ = false;
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if(!(address & 1)) nmi_is_enabled_ = is_zx81;
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if(is_zx81 && !nmi_is_enabled_) z80_.set_wait_line(false);
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// The below emulates the ZonX AY expansion device.
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if constexpr (is_zx81) {
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if((address&0xef) == 0xcf) {
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ay_set_register(*cycle.value);
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} else if((address&0xef) == 0x0f) {
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ay_set_data(*cycle.value);
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}
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}
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break;
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case CPU::Z80::PartialMachineCycle::Input: {
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uint8_t value = 0xff;
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if(!(address&1)) {
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if(!nmi_is_enabled_) set_vsync(true);
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value &= keyboard_.read(address);
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value &= ~(tape_player_.get_input() ? 0x00 : 0x80);
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}
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// The below emulates the ZonX AY expansion device.
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if constexpr (is_zx81) {
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if((address&0xef) == 0xcf) {
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value &= ay_read_data();
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}
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}
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*cycle.value = value;
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} break;
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case CPU::Z80::PartialMachineCycle::Interrupt:
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// resetting event is M1 and IOREQ both simultaneously having leading edges;
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// that happens 2 cycles before the end of INTACK. So the timer was reset and
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// now has advanced twice.
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horizontal_counter_ = HalfCycles(2);
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*cycle.value = 0xff;
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break;
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case CPU::Z80::PartialMachineCycle::Refresh:
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// The ZX80 and 81 signal an interrupt while refresh is active and bit 6 of the refresh
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// address is low. The Z80 signals a refresh, providing the refresh address during the
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// final two cycles of an opcode fetch. Therefore communicate a transient signalling
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// of the IRQ line if necessary.
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if(!(address & 0x40)) {
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z80_.set_interrupt_line(true, Cycles(-2));
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z80_.set_interrupt_line(false);
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}
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if(has_latched_video_byte_) {
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std::size_t char_address = size_t((address & 0xfe00) | ((latched_video_byte_ & 0x3f) << 3) | line_counter_);
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const uint8_t mask = (latched_video_byte_ & 0x80) ? 0x00 : 0xff;
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if(char_address < ram_base_) {
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latched_video_byte_ = rom_[char_address & rom_mask_] ^ mask;
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} else {
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latched_video_byte_ = ram_[address & ram_mask_] ^ mask;
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}
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video_.output_byte(latched_video_byte_);
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has_latched_video_byte_ = false;
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}
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break;
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case CPU::Z80::PartialMachineCycle::ReadOpcode:
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// Check for use of the fast tape hack.
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if(use_fast_tape_hack_ && address == tape_trap_address_) {
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const uint64_t prior_offset = tape_player_.get_tape()->get_offset();
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const int next_byte = parser_.get_next_byte(tape_player_.get_tape());
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if(next_byte != -1) {
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const uint16_t hl = z80_.get_value_of_register(CPU::Z80::Register::HL);
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ram_[hl & ram_mask_] = uint8_t(next_byte);
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*cycle.value = 0x00;
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z80_.set_value_of_register(CPU::Z80::Register::ProgramCounter, tape_return_address_ - 1);
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// Assume that having read one byte quickly, we're probably going to be asked to read
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// another shortly. Therefore, temporarily disable the tape motor for 1000 cycles in order
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// to avoid fighting with real time. This is a stop-gap fix.
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tape_advance_delay_ = 1000;
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return 0;
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} else {
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tape_player_.get_tape()->set_offset(prior_offset);
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}
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}
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if(should_autorun_ && address == finished_load_address_) {
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type_string(is_zx81 ? "r \n" : "r\n "); // Spaces here are not especially scientific; they merely ensure sufficient pauses for both the ZX80 and 81, empirically.
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should_autorun_ = false;
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}
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// Check for automatic tape control.
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if(use_automatic_tape_motor_control_) {
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tape_player_.set_motor_control((address >= automatic_tape_motor_start_address_) && (address < automatic_tape_motor_end_address_));
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}
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is_opcode_read = true;
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[[fallthrough]];
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case CPU::Z80::PartialMachineCycle::Read:
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if(address < ram_base_) {
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*cycle.value = rom_[address & rom_mask_];
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} else {
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const uint8_t value = ram_[address & ram_mask_];
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// If this is an M1 cycle reading from above the 32kb mark and HALT is not
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// currently active, latch for video output and return a NOP. Otherwise,
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// just return the value as read.
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if(is_opcode_read && address&0x8000 && !(value & 0x40) && !z80_.get_halt_line()) {
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latched_video_byte_ = value;
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has_latched_video_byte_ = true;
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*cycle.value = 0;
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} else *cycle.value = value;
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}
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break;
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case CPU::Z80::PartialMachineCycle::Write:
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if(address >= ram_base_) {
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ram_[address & ram_mask_] = *cycle.value;
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}
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break;
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default: break;
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}
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if(typer_) typer_->run_for(cycle.length);
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return HalfCycles(0);
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}
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forceinline void flush() {
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video_.flush();
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if constexpr (is_zx81) {
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update_audio();
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audio_queue_.perform();
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}
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}
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void set_scan_target(Outputs::Display::ScanTarget *scan_target) final {
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video_.set_scan_target(scan_target);
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}
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Outputs::Display::ScanStatus get_scaled_scan_status() const final {
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return video_.get_scaled_scan_status();
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}
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Outputs::Speaker::Speaker *get_speaker() final {
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return is_zx81 ? &speaker_ : nullptr;
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}
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void run_for(const Cycles cycles) final {
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z80_.run_for(cycles);
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}
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bool insert_media(const Analyser::Static::Media &media) final {
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if(!media.tapes.empty()) {
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tape_player_.set_tape(media.tapes.front());
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}
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set_use_fast_tape();
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return !media.tapes.empty();
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}
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void type_string(const std::string &string) final {
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Utility::TypeRecipient<CharacterMapper>::add_typer(string);
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}
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bool can_type(char c) const final {
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return Utility::TypeRecipient<CharacterMapper>::can_type(c);
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}
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// MARK: - Keyboard
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void set_key_state(uint16_t key, bool is_pressed) final {
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keyboard_.set_key_state(key, is_pressed);
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}
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void clear_all_keys() final {
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keyboard_.clear_all_keys();
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}
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static constexpr Sinclair::ZX::Keyboard::Machine keyboard_machine() {
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return is_zx81 ? Sinclair::ZX::Keyboard::Machine::ZX81 : Sinclair::ZX::Keyboard::Machine::ZX80;
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}
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// MARK: - Tape control
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void set_use_automatic_tape_motor_control(bool enabled) {
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use_automatic_tape_motor_control_ = enabled;
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if(!enabled) {
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tape_player_.set_motor_control(false);
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}
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}
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void set_tape_is_playing(bool is_playing) final {
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tape_player_.set_motor_control(is_playing);
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}
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bool get_tape_is_playing() final {
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return tape_player_.get_motor_control();
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}
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// MARK: - Typer timing
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HalfCycles get_typer_delay(const std::string &) const final {
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return z80_.get_is_resetting() ? Cycles(7'000'000) : Cycles(0);
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}
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HalfCycles get_typer_frequency() const final {
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return Cycles(146'250);
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}
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KeyboardMapper *get_keyboard_mapper() final {
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return &keyboard_mapper_;
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}
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// MARK: - Configuration options.
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std::unique_ptr<Reflection::Struct> get_options() final {
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auto options = std::make_unique<Options>(Configurable::OptionsType::UserFriendly); // OptionsType is arbitrary, but not optional.
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options->automatic_tape_motor_control = use_automatic_tape_motor_control_;
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options->quickload = allow_fast_tape_hack_;
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return options;
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}
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void set_options(const std::unique_ptr<Reflection::Struct> &str) {
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const auto options = dynamic_cast<Options *>(str.get());
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set_use_automatic_tape_motor_control(options->automatic_tape_motor_control);
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allow_fast_tape_hack_ = options->quickload;
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set_use_fast_tape();
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}
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private:
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CPU::Z80::Processor<ConcreteMachine, false, is_zx81> z80_;
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Video video_;
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// If fast tape loading is enabled then the PC will be trapped at tape_trap_address_;
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// the emulator will then do a high-level reinterpretation of the standard ZX80/81 reading
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// of a single byte, and the next thing executed will be at tape_return_address_;
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static constexpr uint16_t tape_trap_address_ = is_zx81 ? 0x37c : 0x220;
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static constexpr uint16_t tape_return_address_ = is_zx81 ? 0x380 : 0x248;
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// If automatic tape motor control is enabled then the tape will be permitted to play any time
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// the program counter is >= automatic_tape_motor_start_address_ and < automatic_tape_motor_end_address_.
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static constexpr uint16_t automatic_tape_motor_start_address_ = is_zx81 ? 0x340 : 0x206;
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static constexpr uint16_t automatic_tape_motor_end_address_ = is_zx81 ? 0x3c3 : 0x24d;
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// When automatically loading, if the PC gets to the finished_load_address_ in order to print 0/0
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// (so it's anything that indicates that loading completed, but the program did not autorun) then the
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// emulator will automatically RUN whatever has been loaded.
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static constexpr uint16_t finished_load_address_ = is_zx81 ?
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0x6d1 : // ZX81: this is the routine that prints 0/0 (i.e. success).
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0x203; // ZX80: this is the JR that exits the ZX80's LOAD and returns to MAIN-EXEC.
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bool should_autorun_ = false;
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std::vector<uint8_t> ram_;
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uint16_t ram_mask_, ram_base_;
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std::vector<uint8_t> rom_;
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uint16_t rom_mask_;
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bool vsync_ = false, hsync_ = false;
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int line_counter_ = 0;
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Sinclair::ZX::Keyboard::Keyboard keyboard_;
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Sinclair::ZX::Keyboard::KeyboardMapper keyboard_mapper_;
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HalfClockReceiver<Storage::Tape::BinaryTapePlayer> tape_player_;
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Storage::Tape::ZX8081::Parser parser_;
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bool nmi_is_enabled_ = false;
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static constexpr auto vsync_start_ = is_zx81 ? HalfCycles(32) : HalfCycles(26);
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static constexpr auto vsync_end_ = is_zx81 ? HalfCycles(64) : HalfCycles(66);
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HalfCycles horizontal_counter_;
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uint8_t latched_video_byte_ = 0;
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bool has_latched_video_byte_ = false;
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bool use_fast_tape_hack_ = false;
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bool allow_fast_tape_hack_ = false;
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void set_use_fast_tape() {
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use_fast_tape_hack_ = allow_fast_tape_hack_ && tape_player_.has_tape();
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}
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bool use_automatic_tape_motor_control_ = true;
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HalfCycles tape_advance_delay_ = 0;
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// MARK: - Video
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inline void set_vsync(bool sync) {
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vsync_ = sync;
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update_sync();
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}
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inline void set_hsync(bool sync) {
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hsync_ = sync;
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update_sync();
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}
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inline void update_sync() {
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video_.set_sync(vsync_ || hsync_);
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}
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// MARK: - Audio
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Concurrency::DeferringAsyncTaskQueue audio_queue_;
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using AY = GI::AY38910::AY38910<false>;
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AY ay_;
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Outputs::Speaker::LowpassSpeaker<AY> speaker_;
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HalfCycles time_since_ay_update_;
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inline void ay_set_register(uint8_t value) {
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update_audio();
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GI::AY38910::Utility::select_register(ay_, value);
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}
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inline void ay_set_data(uint8_t value) {
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update_audio();
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GI::AY38910::Utility::write_data(ay_, value);
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}
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inline uint8_t ay_read_data() {
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update_audio();
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return GI::AY38910::Utility::read(ay_);
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|
}
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inline void update_audio() {
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|
speaker_.run_for(audio_queue_, time_since_ay_update_.divide_cycles(Cycles(2)));
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|
}
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|
};
|
|
|
|
}
|
|
}
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|
|
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using namespace Sinclair::ZX8081;
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|
|
|
// See header; constructs and returns an instance of the ZX80 or 81.
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|
Machine *Machine::ZX8081(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
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|
const auto zx_target = dynamic_cast<const Analyser::Static::ZX8081::Target *>(target);
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|
|
|
// Instantiate the correct type of machine.
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|
if(zx_target->is_ZX81) return new ConcreteMachine<true>(*zx_target, rom_fetcher);
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|
else return new ConcreteMachine<false>(*zx_target, rom_fetcher);
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|
}
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|
|
|
Machine::~Machine() {}
|