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536 lines
16 KiB
C++
536 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 "../ConfigurationTarget.hpp"
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#include "../CRTMachine.hpp"
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#include "../KeyboardMachine.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 "../../Configurable/StandardOptions.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.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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const 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 ZX8081 {
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enum ROMType: uint8_t {
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ZX80 = 0, ZX81
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};
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std::vector<std::unique_ptr<Configurable::Option>> get_options() {
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return Configurable::standard_options(
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static_cast<Configurable::StandardOptions>(Configurable::AutomaticTapeMotorControl | Configurable::QuickLoadTape)
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);
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}
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template<bool is_zx81> class ConcreteMachine:
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public CRTMachine::Machine,
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public ConfigurationTarget::Machine,
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public KeyboardMachine::Machine,
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public Configurable::Device,
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public Utility::TypeRecipient,
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public CPU::Z80::BusHandler,
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public Machine {
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public:
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ConcreteMachine() :
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z80_(*this),
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tape_player_(ZX8081ClockRate),
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ay_(audio_queue_),
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speaker_(ay_) {
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set_clock_rate(ZX8081ClockRate);
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speaker_.set_input_rate(static_cast<float>(ZX8081ClockRate) / 2.0f);
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clear_all_keys();
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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(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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// The below emulates the ZonX AY expansion device.
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if(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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uint16_t mask = 0x100;
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for(int c = 0; c < 8; c++) {
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if(!(address & mask)) value &= key_states_[c];
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mask <<= 1;
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}
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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(is_zx81) {
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if((address&0xef) == 0x0f) {
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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 = static_cast<std::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_] = static_cast<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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// 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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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(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 setup_output(float aspect_ratio) override final {
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video_.reset(new Video);
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}
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void close_output() override final {
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video_.reset();
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}
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Outputs::CRT::CRT *get_crt() override final {
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return video_->get_crt();
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}
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Outputs::Speaker::Speaker *get_speaker() override final {
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return is_zx81 ? &speaker_ : nullptr;
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}
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void run_for(const Cycles cycles) override final {
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z80_.run_for(cycles);
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}
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void configure_as_target(const Analyser::Static::Target *target) override final {
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auto *const zx8081_target = dynamic_cast<const Analyser::Static::ZX8081::Target *>(target);
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is_zx81_ = zx8081_target->is_ZX81;
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if(is_zx81_) {
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rom_ = zx81_rom_;
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tape_trap_address_ = 0x37c;
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tape_return_address_ = 0x380;
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vsync_start_ = HalfCycles(32);
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vsync_end_ = HalfCycles(64);
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automatic_tape_motor_start_address_ = 0x0340;
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automatic_tape_motor_end_address_ = 0x03c3;
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} else {
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rom_ = zx8081_target->ZX80_uses_ZX81_ROM ? zx81_rom_ : zx80_rom_;
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tape_trap_address_ = 0x220;
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tape_return_address_ = 0x248;
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vsync_start_ = HalfCycles(26);
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vsync_end_ = HalfCycles(66);
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automatic_tape_motor_start_address_ = 0x0206;
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automatic_tape_motor_end_address_ = 0x024d;
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}
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rom_mask_ = static_cast<uint16_t>(rom_.size() - 1);
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switch(zx8081_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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if(!zx8081_target->loading_command.empty()) {
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type_string(zx8081_target->loading_command);
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}
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insert_media(target->media);
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}
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bool insert_media(const Analyser::Static::Media &media) override 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) override final {
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std::unique_ptr<CharacterMapper> mapper(new CharacterMapper(is_zx81_));
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Utility::TypeRecipient::add_typer(string, std::move(mapper));
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}
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// Obtains the system ROMs.
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bool set_rom_fetcher(const ROMMachine::ROMFetcher &roms_with_names) override {
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const auto roms = roms_with_names(
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"ZX8081",
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{
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"zx80.rom", "zx81.rom",
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});
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for(std::size_t index = 0; index < roms.size(); ++index) {
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if(!roms[index]) return false;
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}
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zx80_rom_ = std::move(*roms[0]);
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zx81_rom_ = std::move(*roms[1]);
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zx80_rom_.resize(4096);
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zx81_rom_.resize(8192);
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return true;
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}
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// MARK: - Keyboard
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void set_key_state(uint16_t key, bool is_pressed) override final {
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if(is_pressed)
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key_states_[key >> 8] &= static_cast<uint8_t>(~key);
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else
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key_states_[key >> 8] |= static_cast<uint8_t>(key);
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}
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void clear_all_keys() override final {
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memset(key_states_, 0xff, 8);
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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) override 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() override 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() override final { return Cycles(7000000); }
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HalfCycles get_typer_frequency() override final { return Cycles(390000); }
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KeyboardMapper *get_keyboard_mapper() override {
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return &keyboard_mapper_;
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}
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// MARK: - Configuration options.
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std::vector<std::unique_ptr<Configurable::Option>> get_options() override {
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return ZX8081::get_options();
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}
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void set_selections(const Configurable::SelectionSet &selections_by_option) override {
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bool quickload;
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if(Configurable::get_quick_load_tape(selections_by_option, quickload)) {
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allow_fast_tape_hack_ = quickload;
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set_use_fast_tape();
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}
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bool autotapemotor;
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if(Configurable::get_automatic_tape_motor_control_selection(selections_by_option, autotapemotor)) {
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set_use_automatic_tape_motor_control(autotapemotor);
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}
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}
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Configurable::SelectionSet get_accurate_selections() override {
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Configurable::SelectionSet selection_set;
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Configurable::append_quick_load_tape_selection(selection_set, false);
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Configurable::append_automatic_tape_motor_control_selection(selection_set, false);
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return selection_set;
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}
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Configurable::SelectionSet get_user_friendly_selections() override {
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Configurable::SelectionSet selection_set;
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Configurable::append_quick_load_tape_selection(selection_set, true);
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Configurable::append_automatic_tape_motor_control_selection(selection_set, true);
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return selection_set;
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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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std::unique_ptr<Video> video_;
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std::vector<uint8_t> zx81_rom_, zx80_rom_;
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uint16_t tape_trap_address_, tape_return_address_;
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uint16_t automatic_tape_motor_start_address_, automatic_tape_motor_end_address_;
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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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uint8_t key_states_[8];
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ZX8081::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 is_zx81_;
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bool nmi_is_enabled_ = false;
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HalfCycles vsync_start_, vsync_end_;
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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_;
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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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GI::AY38910::AY38910 ay_;
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Outputs::Speaker::LowpassSpeaker<GI::AY38910::AY38910> speaker_;
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|
HalfCycles time_since_ay_update_;
|
|
inline void ay_set_register(uint8_t value) {
|
|
update_audio();
|
|
ay_.set_control_lines(GI::AY38910::BC1);
|
|
ay_.set_data_input(value);
|
|
ay_.set_control_lines(GI::AY38910::ControlLines(0));
|
|
}
|
|
inline void ay_set_data(uint8_t value) {
|
|
update_audio();
|
|
ay_.set_control_lines(GI::AY38910::ControlLines(GI::AY38910::BC2 | GI::AY38910::BDIR));
|
|
ay_.set_data_input(value);
|
|
ay_.set_control_lines(GI::AY38910::ControlLines(0));
|
|
}
|
|
inline uint8_t ay_read_data() {
|
|
update_audio();
|
|
ay_.set_control_lines(GI::AY38910::ControlLines(GI::AY38910::BC2 | GI::AY38910::BC1));
|
|
const uint8_t value = ay_.get_data_output();
|
|
ay_.set_control_lines(GI::AY38910::ControlLines(0));
|
|
return value;
|
|
}
|
|
inline void update_audio() {
|
|
speaker_.run_for(audio_queue_, time_since_ay_update_.divide_cycles(Cycles(2)));
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
using namespace ZX8081;
|
|
|
|
// See header; constructs and returns an instance of the ZX80 or 81.
|
|
Machine *Machine::ZX8081(const Analyser::Static::Target *target_hint) {
|
|
const Analyser::Static::ZX8081::Target *const hint = dynamic_cast<const Analyser::Static::ZX8081::Target *>(target_hint);
|
|
|
|
// Instantiate the correct type of machine.
|
|
if(hint->is_ZX81)
|
|
return new ZX8081::ConcreteMachine<true>();
|
|
else
|
|
return new ZX8081::ConcreteMachine<false>();
|
|
}
|
|
|
|
Machine::~Machine() {}
|