1
0
mirror of https://github.com/TomHarte/CLK.git synced 2024-11-22 12:33:29 +00:00
CLK/Machines/Sinclair/ZXSpectrum/ZXSpectrum.cpp

899 lines
27 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//
// ZXSpectrum.cpp
// Clock Signal
//
// Created by Thomas Harte on 17/03/2021.
// Copyright © 2021 Thomas Harte. All rights reserved.
//
#include "ZXSpectrum.hpp"
#include "Video.hpp"
#define LOG_PREFIX "[Spectrum] "
#include "../../../Activity/Source.hpp"
#include "../../MachineTypes.hpp"
#include "../../../Processors/Z80/Z80.hpp"
#include "../../../Components/AudioToggle/AudioToggle.hpp"
#include "../../../Components/AY38910/AY38910.hpp"
// TODO: possibly there's a better factoring than this, but for now
// just grab the CPC's version of an FDC.
#include "../../AmstradCPC/FDC.hpp"
#include "../../../Outputs/Log.hpp"
#include "../../../Outputs/Speaker/Implementation/CompoundSource.hpp"
#include "../../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
#include "../../../Outputs/Speaker/Implementation/SampleSource.hpp"
#include "../../../Storage/Tape/Tape.hpp"
#include "../../../Storage/Tape/Parsers/Spectrum.hpp"
#include "../../../Analyser/Static/ZXSpectrum/Target.hpp"
#include "../../Utility/MemoryFuzzer.hpp"
#include "../../Utility/Typer.hpp"
#include "../../../ClockReceiver/JustInTime.hpp"
#include "../../../Processors/Z80/State/State.hpp"
#include "../Keyboard/Keyboard.hpp"
#include <array>
namespace Sinclair {
namespace ZXSpectrum {
using Model = Analyser::Static::ZXSpectrum::Target::Model;
using CharacterMapper = Sinclair::ZX::Keyboard::CharacterMapper;
template<Model model> class ConcreteMachine:
public Activity::Source,
public ClockingHint::Observer,
public Configurable::Device,
public CPU::Z80::BusHandler,
public Machine,
public MachineTypes::AudioProducer,
public MachineTypes::MappedKeyboardMachine,
public MachineTypes::MediaTarget,
public MachineTypes::ScanProducer,
public MachineTypes::TimedMachine,
public Utility::TypeRecipient<CharacterMapper> {
public:
ConcreteMachine(const Analyser::Static::ZXSpectrum::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
Utility::TypeRecipient<CharacterMapper>(Sinclair::ZX::Keyboard::Machine::ZXSpectrum),
z80_(*this),
ay_(GI::AY38910::Personality::AY38910, audio_queue_),
audio_toggle_(audio_queue_),
mixer_(ay_, audio_toggle_),
speaker_(mixer_),
keyboard_(Sinclair::ZX::Keyboard::Machine::ZXSpectrum),
keyboard_mapper_(Sinclair::ZX::Keyboard::Machine::ZXSpectrum),
tape_player_(clock_rate() * 2),
fdc_(clock_rate() * 2)
{
set_clock_rate(clock_rate());
speaker_.set_input_rate(float(clock_rate()) / 2.0f);
// With only the +2a and +3 currently supported, the +3 ROM is always
// the one required.
std::vector<ROMMachine::ROM> rom_names;
const std::string machine = "ZXSpectrum";
switch(model) {
case Model::SixteenK:
case Model::FortyEightK:
rom_names.emplace_back(machine, "the 48kb ROM", "48.rom", 16 * 1024, 0xddee531f);
break;
case Model::OneTwoEightK:
rom_names.emplace_back(machine, "the 128kb ROM", "128.rom", 32 * 1024, 0x2cbe8995);
break;
case Model::Plus2:
rom_names.emplace_back(machine, "the +2 ROM", "plus2.rom", 32 * 1024, 0xe7a517dc);
break;
case Model::Plus2a:
case Model::Plus3: {
const std::initializer_list<uint32_t> crc32s = { 0x96e3c17a, 0xbe0d9ec4 };
rom_names.emplace_back(machine, "the +2a/+3 ROM", "plus3.rom", 64 * 1024, crc32s);
} break;
}
const auto roms = rom_fetcher(rom_names);
if(!roms[0]) throw ROMMachine::Error::MissingROMs;
memcpy(rom_.data(), roms[0]->data(), std::min(rom_.size(), roms[0]->size()));
// Register for sleeping notifications.
tape_player_.set_clocking_hint_observer(this);
// Set up initial memory map.
update_memory_map();
set_video_address();
Memory::Fuzz(ram_);
// Insert media.
insert_media(target.media);
// Possibly depress the enter key.
if(target.should_hold_enter) {
// Hold it for five seconds, more or less.
duration_to_press_enter_ = Cycles(5 * clock_rate());
keyboard_.set_key_state(ZX::Keyboard::KeyEnter, true);
}
}
~ConcreteMachine() {
audio_queue_.flush();
}
static constexpr unsigned int clock_rate() {
constexpr unsigned int OriginalClockRate = 3'500'000;
constexpr unsigned int Plus3ClockRate = 3'546'875; // See notes below; this is a guess.
// Notes on timing for the +2a and +3:
//
// Standard PAL produces 283.7516 colour cycles per line, each line being 64µs.
// The oft-quoted 3.5469 Mhz would seem to imply 227.0016 clock cycles per line.
// Since those Spectrums actually produce 228 cycles per line, but software like
// Chromatrons seems to assume a fixed phase relationship, I guess that the real
// clock speed is whatever gives:
//
// 228 / [cycles per line] * 283.7516 = [an integer].
//
// i.e. 228 * 283.7516 = [an integer] * [cycles per line], such that cycles per line ~= 227
// ... which would imply that 'an integer' is probably 285, i.e.
//
// 228 / [cycles per line] * 283.7516 = 285
// => 227.00128 = [cycles per line]
// => clock rate = 3.546895 Mhz?
//
// That is... unless I'm mistaken about the PAL colour subcarrier and it's actually 283.75,
// which would give exactly 227 cycles/line and therefore 3.546875 Mhz.
//
// A real TV would be likely to accept either, I guess. But it does seem like
// the Spectrum is a PAL machine with a fixed colour phase relationship. For
// this emulator's world, that's a first!
return model < Model::OneTwoEightK ? OriginalClockRate : Plus3ClockRate;
}
// MARK: - TimedMachine.
void run_for(const Cycles cycles) override {
z80_.run_for(cycles);
// Use this very broad timing base for the automatic enter depression.
// It's not worth polluting the main loop.
if(duration_to_press_enter_ > Cycles(0)) {
if(duration_to_press_enter_ < cycles) {
duration_to_press_enter_ = Cycles(0);
keyboard_.set_key_state(ZX::Keyboard::KeyEnter, false);
} else {
duration_to_press_enter_ -= cycles;
}
}
}
void flush() {
video_.flush();
update_audio();
audio_queue_.perform();
if constexpr (model == Model::Plus3) {
fdc_.flush();
}
}
// MARK: - ScanProducer.
void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
video_->set_scan_target(scan_target);
}
Outputs::Display::ScanStatus get_scaled_scan_status() const override {
return video_->get_scaled_scan_status();
}
void set_display_type(Outputs::Display::DisplayType display_type) override {
video_->set_display_type(display_type);
}
// MARK: - BusHandler.
forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
using PartialMachineCycle = CPU::Z80::PartialMachineCycle;
const uint16_t address = cycle.address ? *cycle.address : 0x0000;
// Apply contention if necessary.
if constexpr (model >= Model::Plus2a) {
// Model applied: the trigger for the ULA inserting a delay is the falling edge
// of MREQ, which is always half a cycle into a read or write.
if(
is_contended_[address >> 14] &&
cycle.operation >= PartialMachineCycle::ReadOpcodeStart &&
cycle.operation <= PartialMachineCycle::WriteStart) {
const HalfCycles delay = video_.last_valid()->access_delay(video_.time_since_flush() + HalfCycles(1));
advance(cycle.length + delay);
return delay;
}
} else {
switch(cycle.operation) {
case CPU::Z80::PartialMachineCycle::Input:
case CPU::Z80::PartialMachineCycle::Output:
case CPU::Z80::PartialMachineCycle::Read:
case CPU::Z80::PartialMachineCycle::Write:
case CPU::Z80::PartialMachineCycle::ReadOpcode:
case CPU::Z80::PartialMachineCycle::Interrupt:
// For these, carry on into the actual handler, below.
break;
// For anything else that isn't listed below, just advance
// time and conclude here.
default:
advance(cycle.length);
return HalfCycles(0);
case CPU::Z80::PartialMachineCycle::InputStart:
case CPU::Z80::PartialMachineCycle::OutputStart: {
// The port address is loaded prior to IOREQ being visible; a contention
// always occurs if it is in the $4000$8000 range regardless of current
// memory mapping.
HalfCycles delay;
HalfCycles time = video_.time_since_flush() + HalfCycles(1);
if((address & 0xc000) == 0x4000) {
for(int c = 0; c < ((address & 1) ? 4 : 2); c++) {
const auto next_delay = video_.last_valid()->access_delay(time);
delay += next_delay;
time += next_delay + 2;
}
} else {
if(!(address & 1)) {
delay = video_.last_valid()->access_delay(time + HalfCycles(2));
}
}
advance(cycle.length + delay);
return delay;
} break;
case PartialMachineCycle::ReadOpcodeStart:
case PartialMachineCycle::ReadStart:
case PartialMachineCycle::WriteStart: {
// These all start by loading the address bus, then set MREQ
// half a cycle later.
if(is_contended_[address >> 14]) {
const HalfCycles delay = video_.last_valid()->access_delay(video_.time_since_flush() + HalfCycles(1));
advance(cycle.length + delay);
return delay;
}
} break;
case PartialMachineCycle::Internal: {
// Whatever's on the address bus will remain there, without IOREQ or
// MREQ interceding, for this entire bus cycle. So apply contentions
// all the way along.
if(is_contended_[address >> 14]) {
const auto half_cycles = cycle.length.as<int>();
assert(!(half_cycles & 1));
HalfCycles time = video_.time_since_flush() + HalfCycles(1);
HalfCycles delay;
for(int c = 0; c < half_cycles; c += 2) {
const auto next_delay = video_.last_valid()->access_delay(time);
delay += next_delay;
time += next_delay + 2;
}
advance(cycle.length + delay);
return delay;
}
} break;
}
}
// For all other machine cycles, model the action as happening at the end of the machine cycle;
// that means advancing time now.
advance(cycle.length);
switch(cycle.operation) {
default: break;
case PartialMachineCycle::ReadOpcode:
// Fast loading: ROM version.
//
// The below patches over part of the 'LD-BYTES' routine from the 48kb ROM.
if(use_fast_tape_hack_ && address == 0x056b && read_pointers_[0] == &rom_[classic_rom_offset()]) {
// Stop pressing enter, if neccessry.
if(duration_to_press_enter_ > Cycles(0)) {
duration_to_press_enter_ = Cycles(0);
keyboard_.set_key_state(ZX::Keyboard::KeyEnter, false);
}
if(perform_rom_ld_bytes_56b()) {
*cycle.value = 0xc9; // i.e. RET.
break;
}
}
case PartialMachineCycle::Read:
if constexpr (model == Model::SixteenK) {
// Assumption: with nothing mapped above 0x8000 on the 16kb Spectrum,
// read the floating bus.
if(address >= 0x8000) {
*cycle.value = video_->get_floating_value();
break;
}
}
*cycle.value = read_pointers_[address >> 14][address];
if constexpr (model >= Model::Plus2a) {
if(is_contended_[address >> 14]) {
video_->set_last_contended_area_access(*cycle.value);
}
}
break;
case PartialMachineCycle::Write:
// Flush video if this access modifies screen contents.
if(is_video_[address >> 14] && (address & 0x3fff) < 6912) {
video_.flush();
}
write_pointers_[address >> 14][address] = *cycle.value;
if constexpr (model >= Model::Plus2a) {
// Fill the floating bus buffer if this write is within the contended area.
if(is_contended_[address >> 14]) {
video_->set_last_contended_area_access(*cycle.value);
}
}
break;
// Partial port decodings here and in ::Input are as documented
// at https://worldofspectrum.org/faq/reference/ports.htm
case PartialMachineCycle::Output:
// Test for port FE.
if(!(address&1)) {
update_audio();
audio_toggle_.set_output(*cycle.value & 0x10);
video_->set_border_colour(*cycle.value & 7);
// b0b2: border colour
// b3: enable tape input (?)
// b4: tape and speaker output
}
// Test for classic 128kb paging register (i.e. port 7ffd).
if (
(model >= Model::OneTwoEightK && model <= Model::Plus2 && (address & 0x8002) == 0x0000) ||
(model >= Model::Plus2a && (address & 0xc002) == 0x4000)
) {
port7ffd_ = *cycle.value;
update_memory_map();
// Set the proper video base pointer.
set_video_address();
// Potentially lock paging, _after_ the current
// port values have taken effect.
disable_paging_ |= *cycle.value & 0x20;
}
// Test for +2a/+3 paging (i.e. port 1ffd).
if constexpr (model >= Model::Plus2a) {
if((address & 0xf002) == 0x1000) {
port1ffd_ = *cycle.value;
update_memory_map();
update_video_base();
if constexpr (model == Model::Plus3) {
fdc_->set_motor_on(*cycle.value & 0x08);
}
}
}
// Route to the AY if one is fitted.
if constexpr (model >= Model::OneTwoEightK) {
switch(address & 0xc002) {
case 0xc000:
// Select AY register.
update_audio();
GI::AY38910::Utility::select_register(ay_, *cycle.value);
break;
case 0x8000:
// Write to AY register.
update_audio();
GI::AY38910::Utility::write_data(ay_, *cycle.value);
break;
}
}
// Check for FDC accesses.
if constexpr (model == Model::Plus3) {
switch(address & 0xf002) {
default: break;
case 0x3000: case 0x2000:
fdc_->write((address >> 12) & 1, *cycle.value);
break;
}
}
break;
case PartialMachineCycle::Input: {
bool did_match = false;
*cycle.value = 0xff;
if(!(address&1)) {
did_match = true;
// Port FE:
//
// address b8+: mask of keyboard lines to select
// result: b0b4: mask of keys pressed
// b6: tape input
*cycle.value &= keyboard_.read(address);
*cycle.value &= tape_player_.get_input() ? 0xbf : 0xff;
// If this read is within 200 cycles of the previous,
// count it as an adjacent hit; if 20 of those have
// occurred then start the tape motor.
if(use_automatic_tape_motor_control_) {
if(cycles_since_tape_input_read_ < HalfCycles(400)) {
++recent_tape_hits_;
if(recent_tape_hits_ == 20) {
tape_player_.set_motor_control(true);
}
} else {
recent_tape_hits_ = 0;
}
cycles_since_tape_input_read_ = HalfCycles(0);
}
}
if constexpr (model >= Model::OneTwoEightK) {
if((address & 0xc002) == 0xc000) {
did_match = true;
// Read from AY register.
update_audio();
*cycle.value &= GI::AY38910::Utility::read(ay_);
}
}
if constexpr (model >= Model::Plus2a) {
// Check for a +2a/+3 floating bus read; these are particularly arcane.
// See footnote to https://spectrumforeveryone.com/technical/memory-contention-floating-bus/
// and, much more rigorously, http://sky.relative-path.com/zx/floating_bus.html
if(!disable_paging_ && (address & 0xf003) == 0x0001) {
*cycle.value &= video_->get_floating_value();
}
}
if constexpr (model == Model::Plus3) {
switch(address & 0xf002) {
default: break;
case 0x3000: case 0x2000:
*cycle.value &= fdc_->read((address >> 12) & 1);
break;
}
}
if constexpr (model <= Model::Plus2) {
if(!did_match) {
*cycle.value = video_->get_floating_value();
}
}
} break;
case PartialMachineCycle::Interrupt:
// At least one piece of Spectrum software, Escape from M.O.N.J.A.S. explicitly
// assumes that a 0xff value will be on the bus during an interrupt acknowledgment.
// I wasn't otherwise aware that this value is reliable.
*cycle.value = 0xff;
break;
}
return HalfCycles(0);
}
private:
void advance(HalfCycles duration) {
time_since_audio_update_ += duration;
video_ += duration;
if(video_.did_flush()) {
z80_.set_interrupt_line(video_.last_valid()->get_interrupt_line(), video_.last_sequence_point_overrun());
}
if(!tape_player_is_sleeping_) tape_player_.run_for(duration.as_integral());
// Update automatic tape motor control, if enabled; if it's been
// 3 seconds since software last possibly polled the tape, stop it.
if(use_automatic_tape_motor_control_ && cycles_since_tape_input_read_ < HalfCycles(clock_rate() * 6)) {
cycles_since_tape_input_read_ += duration;
if(cycles_since_tape_input_read_ >= HalfCycles(clock_rate() * 6)) {
tape_player_.set_motor_control(false);
recent_tape_hits_ = 0;
}
}
if constexpr (model == Model::Plus3) {
fdc_ += Cycles(duration.as_integral());
}
if(typer_) typer_->run_for(duration);
}
void type_string(const std::string &string) override {
Utility::TypeRecipient<CharacterMapper>::add_typer(string);
}
bool can_type(char c) const override {
return Utility::TypeRecipient<CharacterMapper>::can_type(c);
}
public:
// MARK: - Typer.
HalfCycles get_typer_delay(const std::string &) const override {
return z80_.get_is_resetting() ? Cycles(7'000'000) : Cycles(0);
}
HalfCycles get_typer_frequency() const override{
return Cycles(70'908);
}
KeyboardMapper *get_keyboard_mapper() override {
return &keyboard_mapper_;
}
// MARK: - Keyboard.
void set_key_state(uint16_t key, bool is_pressed) override {
keyboard_.set_key_state(key, is_pressed);
}
void clear_all_keys() override {
keyboard_.clear_all_keys();
// Caveat: if holding enter synthetically, continue to do so.
if(duration_to_press_enter_ > Cycles(0)) {
keyboard_.set_key_state(ZX::Keyboard::KeyEnter, true);
}
}
// MARK: - MediaTarget.
bool insert_media(const Analyser::Static::Media &media) override {
// If there are any tapes supplied, use the first of them.
if(!media.tapes.empty()) {
tape_player_.set_tape(media.tapes.front());
set_use_fast_tape();
}
// Insert up to four disks.
int c = 0;
for(auto &disk : media.disks) {
fdc_->set_disk(disk, c);
c++;
if(c == 4) break;
}
return !media.tapes.empty() || (!media.disks.empty() && model == Model::Plus3);
}
// MARK: - ClockingHint::Observer.
void set_component_prefers_clocking(ClockingHint::Source *, ClockingHint::Preference) override {
tape_player_is_sleeping_ = tape_player_.preferred_clocking() == ClockingHint::Preference::None;
}
// MARK: - Tape control.
void set_use_automatic_tape_motor_control(bool enabled) {
use_automatic_tape_motor_control_ = enabled;
if(!enabled) {
tape_player_.set_motor_control(false);
}
}
void set_tape_is_playing(bool is_playing) final {
tape_player_.set_motor_control(is_playing);
}
bool get_tape_is_playing() final {
return tape_player_.get_motor_control();
}
// MARK: - Configuration options.
std::unique_ptr<Reflection::Struct> get_options() override {
auto options = std::make_unique<Options>(Configurable::OptionsType::UserFriendly); // OptionsType is arbitrary, but not optional.
options->automatic_tape_motor_control = use_automatic_tape_motor_control_;
options->quickload = allow_fast_tape_hack_;
return options;
}
void set_options(const std::unique_ptr<Reflection::Struct> &str) override {
const auto options = dynamic_cast<Options *>(str.get());
set_video_signal_configurable(options->output);
set_use_automatic_tape_motor_control(options->automatic_tape_motor_control);
allow_fast_tape_hack_ = options->quickload;
set_use_fast_tape();
}
// MARK: - AudioProducer.
Outputs::Speaker::Speaker *get_speaker() override {
return &speaker_;
}
// MARK: - Activity Source.
void set_activity_observer(Activity::Observer *observer) override {
if constexpr (model == Model::Plus3) fdc_->set_activity_observer(observer);
tape_player_.set_activity_observer(observer);
}
private:
CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
// MARK: - Memory.
std::array<uint8_t, 64*1024> rom_;
std::array<uint8_t, 128*1024> ram_;
std::array<uint8_t, 16*1024> scratch_;
const uint8_t *read_pointers_[4];
uint8_t *write_pointers_[4];
uint8_t pages_[4];
bool is_contended_[4];
bool is_video_[4];
uint8_t port1ffd_ = 0;
uint8_t port7ffd_ = 0;
bool disable_paging_ = false;
void update_memory_map() {
// If paging is permanently disabled, don't react.
if(disable_paging_) {
return;
}
if(port1ffd_ & 0x01) {
// "Special paging mode", i.e. one of four fixed
// RAM configurations, port 7ffd doesn't matter.
switch(port1ffd_ & 0x06) {
default:
case 0x00:
set_memory(0, 0);
set_memory(1, 1);
set_memory(2, 2);
set_memory(3, 3);
break;
case 0x02:
set_memory(0, 4);
set_memory(1, 5);
set_memory(2, 6);
set_memory(3, 7);
break;
case 0x04:
set_memory(0, 4);
set_memory(1, 5);
set_memory(2, 6);
set_memory(3, 3);
break;
case 0x06:
set_memory(0, 4);
set_memory(1, 7);
set_memory(2, 6);
set_memory(3, 3);
break;
}
} else {
// Apply standard 128kb-esque mapping (albeit with extra ROM to pick from).
set_memory(0, 0x80 | ((port1ffd_ >> 1) & 2) | ((port7ffd_ >> 4) & 1));
set_memory(1, 5);
set_memory(2, 2);
set_memory(3, port7ffd_ & 7);
}
}
void set_memory(int bank, uint8_t source) {
if constexpr (model >= Model::Plus2a) {
is_contended_[bank] = (source >= 4 && source < 8);
} else {
is_contended_[bank] = source & 1;
}
pages_[bank] = source;
uint8_t *const read = (source < 0x80) ? &ram_[source * 16384] : &rom_[(source & 0x7f) * 16384];
const auto offset = bank*16384;
read_pointers_[bank] = read - offset;
write_pointers_[bank] = ((source < 0x80) ? read : scratch_.data()) - offset;
}
void set_video_address() {
video_->set_video_source(&ram_[((port7ffd_ & 0x08) ? 7 : 5) * 16384]);
update_video_base();
}
void update_video_base() {
const uint8_t video_page = (port7ffd_ & 0x08) ? 7 : 5;
is_video_[0] = pages_[0] == video_page;
is_video_[1] = pages_[1] == video_page;
is_video_[2] = pages_[2] == video_page;
is_video_[3] = pages_[3] == video_page;
}
// MARK: - Audio.
Concurrency::DeferringAsyncTaskQueue audio_queue_;
GI::AY38910::AY38910<false> ay_;
Audio::Toggle audio_toggle_;
Outputs::Speaker::CompoundSource<GI::AY38910::AY38910<false>, Audio::Toggle> mixer_;
Outputs::Speaker::LowpassSpeaker<Outputs::Speaker::CompoundSource<GI::AY38910::AY38910<false>, Audio::Toggle>> speaker_;
HalfCycles time_since_audio_update_;
void update_audio() {
speaker_.run_for(audio_queue_, time_since_audio_update_.divide_cycles(Cycles(2)));
}
// MARK: - Video.
using VideoType =
std::conditional_t<
model <= Model::FortyEightK, Video<VideoTiming::FortyEightK>,
std::conditional_t<
model <= Model::Plus2, Video<VideoTiming::OneTwoEightK>,
Video<VideoTiming::Plus3>
>
>;
JustInTimeActor<VideoType> video_;
// MARK: - Keyboard.
Sinclair::ZX::Keyboard::Keyboard keyboard_;
Sinclair::ZX::Keyboard::KeyboardMapper keyboard_mapper_;
// MARK: - Tape.
Storage::Tape::BinaryTapePlayer tape_player_;
bool tape_player_is_sleeping_ = false;
bool use_automatic_tape_motor_control_ = true;
HalfCycles cycles_since_tape_input_read_;
int recent_tape_hits_ = 0;
bool allow_fast_tape_hack_ = false;
bool use_fast_tape_hack_ = false;
void set_use_fast_tape() {
use_fast_tape_hack_ = allow_fast_tape_hack_ && tape_player_.has_tape();
}
// Reimplements the 'LD-BYTES' routine, as documented at
// https://skoolkid.github.io/rom/asm/0556.html but picking
// up from address 56b i.e.
//
// In:
// A': 0x00 or 0xff for block type;
// F': carry set if loading, clear if verifying;
// DE: block length;
// IX: start address.
//
// Out:
// F: carry set for success, clear for error.
//
// And, empirically:
// IX: one beyond final address written;
// DE: 0;
// L: parity byte;
// H: 0 for no error, 0xff for error;
// A: same as H.
// BC: ???
bool perform_rom_ld_bytes_56b() {
using Parser = Storage::Tape::ZXSpectrum::Parser;
Parser parser(Parser::MachineType::ZXSpectrum);
using Register = CPU::Z80::Register;
uint8_t flags = uint8_t(z80_.get_value_of_register(Register::FlagsDash));
if(!(flags & 1)) return false;
const uint8_t block_type = uint8_t(z80_.get_value_of_register(Register::ADash));
const auto block = parser.find_block(tape_player_.get_tape());
if(!block || block_type != (*block).type) return false;
uint16_t length = z80_.get_value_of_register(Register::DE);
uint16_t target = z80_.get_value_of_register(Register::IX);
flags = 0x93;
uint8_t parity = 0x00;
while(length--) {
auto next = parser.get_byte(tape_player_.get_tape());
if(!next) {
flags &= ~1;
break;
}
write_pointers_[target >> 14][target] = *next;
parity ^= *next;
++target;
}
auto stored_parity = parser.get_byte(tape_player_.get_tape());
if(!stored_parity) {
flags &= ~1;
} else {
z80_.set_value_of_register(Register::L, *stored_parity);
}
z80_.set_value_of_register(Register::Flags, flags);
z80_.set_value_of_register(Register::DE, length);
z80_.set_value_of_register(Register::IX, target);
const uint8_t h = (flags & 1) ? 0x00 : 0xff;
z80_.set_value_of_register(Register::H, h);
z80_.set_value_of_register(Register::A, h);
return true;
}
static constexpr int classic_rom_offset() {
switch(model) {
case Model::SixteenK:
case Model::FortyEightK:
return 0x0000;
case Model::OneTwoEightK:
case Model::Plus2:
return 0x4000;
case Model::Plus2a:
case Model::Plus3:
return 0xc000;
}
}
// MARK: - Disc.
JustInTimeActor<Amstrad::FDC, Cycles> fdc_;
// MARK: - Automatic startup.
Cycles duration_to_press_enter_;
};
}
}
using namespace Sinclair::ZXSpectrum;
Machine *Machine::ZXSpectrum(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
const auto zx_target = dynamic_cast<const Analyser::Static::ZXSpectrum::Target *>(target);
switch(zx_target->model) {
case Model::SixteenK: return new ConcreteMachine<Model::SixteenK>(*zx_target, rom_fetcher);
case Model::FortyEightK: return new ConcreteMachine<Model::FortyEightK>(*zx_target, rom_fetcher);
case Model::OneTwoEightK: return new ConcreteMachine<Model::OneTwoEightK>(*zx_target, rom_fetcher);
case Model::Plus2: return new ConcreteMachine<Model::Plus2>(*zx_target, rom_fetcher);
case Model::Plus2a: return new ConcreteMachine<Model::Plus2a>(*zx_target, rom_fetcher);
case Model::Plus3: return new ConcreteMachine<Model::Plus3>(*zx_target, rom_fetcher);
}
return nullptr;
}
Machine::~Machine() {}