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CLK/Machines/Electron/Electron.cpp
Thomas Harte be01203cc1 Starts to expand the range of supported 6502s.
This fully implements the NES 6502 because, well, it's virtually no extra work, and ensures that RDY takes effect on write cycles on 65C02s.
2018-08-13 22:17:22 -04:00

611 lines
19 KiB
C++

//
// Electron.cpp
// Clock Signal
//
// Created by Thomas Harte on 03/01/2016.
// Copyright 2016 Thomas Harte. All rights reserved.
//
#include "Electron.hpp"
#include "../../Activity/Source.hpp"
#include "../MediaTarget.hpp"
#include "../CRTMachine.hpp"
#include "../KeyboardMachine.hpp"
#include "../../ClockReceiver/ClockReceiver.hpp"
#include "../../ClockReceiver/ForceInline.hpp"
#include "../../Configurable/StandardOptions.hpp"
#include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
#include "../../Processors/6502/6502.hpp"
#include "../../Storage/Tape/Tape.hpp"
#include "../Utility/Typer.hpp"
#include "../../Analyser/Static/Acorn/Target.hpp"
#include "Interrupts.hpp"
#include "Keyboard.hpp"
#include "Plus3.hpp"
#include "SoundGenerator.hpp"
#include "Tape.hpp"
#include "Video.hpp"
namespace Electron {
std::vector<std::unique_ptr<Configurable::Option>> get_options() {
return Configurable::standard_options(
static_cast<Configurable::StandardOptions>(Configurable::DisplayRGB | Configurable::DisplayComposite | Configurable::QuickLoadTape)
);
}
class ConcreteMachine:
public Machine,
public CRTMachine::Machine,
public MediaTarget::Machine,
public KeyboardMachine::Machine,
public Configurable::Device,
public CPU::MOS6502::BusHandler,
public Tape::Delegate,
public Utility::TypeRecipient,
public Activity::Source {
public:
ConcreteMachine(const Analyser::Static::Acorn::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
m6502_(*this),
sound_generator_(audio_queue_),
speaker_(sound_generator_) {
memset(key_states_, 0, sizeof(key_states_));
for(int c = 0; c < 16; c++)
memset(roms_[c], 0xff, 16384);
tape_.set_delegate(this);
set_clock_rate(2000000);
speaker_.set_input_rate(2000000 / SoundGenerator::clock_rate_divider);
std::vector<std::string> rom_names = {"basic.rom", "os.rom"};
if(target.has_adfs) {
rom_names.push_back("ADFS-E00_1.rom");
rom_names.push_back("ADFS-E00_2.rom");
}
const size_t dfs_rom_position = rom_names.size();
if(target.has_dfs) {
rom_names.push_back("DFS-1770-2.20.rom");
}
const auto roms = rom_fetcher("Electron", rom_names);
for(const auto &rom: roms) {
if(!rom) {
throw ROMMachine::Error::MissingROMs;
}
}
set_rom(ROM::BASIC, *roms[0], false);
set_rom(ROM::OS, *roms[1], false);
if(target.has_dfs || target.has_adfs) {
plus3_.reset(new Plus3);
if(target.has_dfs) {
set_rom(ROM::Slot0, *roms[dfs_rom_position], true);
}
if(target.has_adfs) {
set_rom(ROM::Slot4, *roms[2], true);
set_rom(ROM::Slot5, *roms[3], true);
}
}
insert_media(target.media);
if(!target.loading_command.empty()) {
type_string(target.loading_command);
}
if(target.should_shift_restart) {
shift_restart_counter_ = 1000000;
}
}
~ConcreteMachine() {
audio_queue_.flush();
}
void set_key_state(uint16_t key, bool isPressed) override final {
if(key == KeyBreak) {
m6502_.set_reset_line(isPressed);
} else {
if(isPressed)
key_states_[key >> 4] |= key&0xf;
else
key_states_[key >> 4] &= ~(key&0xf);
}
}
void clear_all_keys() override final {
memset(key_states_, 0, sizeof(key_states_));
if(is_holding_shift_) set_key_state(KeyShift, true);
}
bool insert_media(const Analyser::Static::Media &media) override final {
if(!media.tapes.empty()) {
tape_.set_tape(media.tapes.front());
}
set_use_fast_tape_hack();
if(!media.disks.empty() && plus3_) {
plus3_->set_disk(media.disks.front(), 0);
}
ROM slot = ROM::Slot12;
for(std::shared_ptr<Storage::Cartridge::Cartridge> cartridge : media.cartridges) {
const ROM first_slot_tried = slot;
while(rom_inserted_[static_cast<int>(slot)]) {
slot = static_cast<ROM>((static_cast<int>(slot) + 1) & 15);
if(slot == first_slot_tried) return false;
}
set_rom(slot, cartridge->get_segments().front().data, false);
}
return !media.tapes.empty() || !media.disks.empty() || !media.cartridges.empty();
}
forceinline Cycles perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
unsigned int cycles = 1;
if(address < 0x8000) {
if(isReadOperation(operation)) {
*value = ram_[address];
} else {
if(address >= video_access_range_.low_address && address <= video_access_range_.high_address) update_display();
ram_[address] = *value;
}
// for the entire frame, RAM is accessible only on odd cycles; in modes below 4
// it's also accessible only outside of the pixel regions
cycles += video_output_->get_cycles_until_next_ram_availability(cycles_since_display_update_.as_int() + 1);
} else {
switch(address & 0xff0f) {
case 0xfe00:
if(isReadOperation(operation)) {
*value = interrupt_status_;
interrupt_status_ &= ~PowerOnReset;
} else {
interrupt_control_ = (*value) & ~1;
evaluate_interrupts();
}
break;
case 0xfe07:
if(!isReadOperation(operation)) {
// update speaker mode
bool new_speaker_is_enabled = (*value & 6) == 2;
if(new_speaker_is_enabled != speaker_is_enabled_) {
update_audio();
sound_generator_.set_is_enabled(new_speaker_is_enabled);
speaker_is_enabled_ = new_speaker_is_enabled;
}
tape_.set_is_enabled((*value & 6) != 6);
tape_.set_is_in_input_mode((*value & 6) == 0);
tape_.set_is_running((*value & 0x40) ? true : false);
caps_led_state_ = !!(*value & 0x80);
if(activity_observer_)
activity_observer_->set_led_status(caps_led, caps_led_state_);
}
// deliberate fallthrough; fe07 contains the display mode.
case 0xfe02: case 0xfe03:
case 0xfe08: case 0xfe09: case 0xfe0a: case 0xfe0b:
case 0xfe0c: case 0xfe0d: case 0xfe0e: case 0xfe0f:
if(!isReadOperation(operation)) {
update_display();
video_output_->set_register(address, *value);
video_access_range_ = video_output_->get_memory_access_range();
queue_next_display_interrupt();
}
break;
case 0xfe04:
if(isReadOperation(operation)) {
*value = tape_.get_data_register();
tape_.clear_interrupts(Interrupt::ReceiveDataFull);
} else {
tape_.set_data_register(*value);
tape_.clear_interrupts(Interrupt::TransmitDataEmpty);
}
break;
case 0xfe05:
if(!isReadOperation(operation)) {
const uint8_t interruptDisable = (*value)&0xf0;
if( interruptDisable ) {
if( interruptDisable&0x10 ) interrupt_status_ &= ~Interrupt::DisplayEnd;
if( interruptDisable&0x20 ) interrupt_status_ &= ~Interrupt::RealTimeClock;
if( interruptDisable&0x40 ) interrupt_status_ &= ~Interrupt::HighToneDetect;
evaluate_interrupts();
// TODO: NMI
}
// latch the paged ROM in case external hardware is being emulated
active_rom_ = *value & 0xf;
// apply the ULA's test
if(*value & 0x08) {
if(*value & 0x04) {
keyboard_is_active_ = false;
basic_is_active_ = false;
} else {
keyboard_is_active_ = !(*value & 0x02);
basic_is_active_ = !keyboard_is_active_;
}
}
}
break;
case 0xfe06:
if(!isReadOperation(operation)) {
update_audio();
sound_generator_.set_divider(*value);
tape_.set_counter(*value);
}
break;
case 0xfc04: case 0xfc05: case 0xfc06: case 0xfc07:
if(plus3_ && (address&0x00f0) == 0x00c0) {
if(is_holding_shift_ && address == 0xfcc4) {
is_holding_shift_ = false;
set_key_state(KeyShift, false);
}
if(isReadOperation(operation))
*value = plus3_->get_register(address);
else
plus3_->set_register(address, *value);
}
break;
case 0xfc00:
if(plus3_ && (address&0x00f0) == 0x00c0) {
if(!isReadOperation(operation)) {
plus3_->set_control_register(*value);
} else *value = 1;
}
break;
default:
if(address >= 0xc000) {
if(isReadOperation(operation)) {
if(
use_fast_tape_hack_ &&
(operation == CPU::MOS6502::BusOperation::ReadOpcode) &&
(
(address == 0xf4e5) || (address == 0xf4e6) || // double NOPs at 0xf4e5, 0xf6de, 0xf6fa and 0xfa51
(address == 0xf6de) || (address == 0xf6df) || // act to disable the normal branch into tape-handling
(address == 0xf6fa) || (address == 0xf6fb) || // code, forcing the OS along the serially-accessed ROM
(address == 0xfa51) || (address == 0xfa52) || // pathway.
(address == 0xf0a8) // 0xf0a8 is from where a service call would normally be
// dispatched; we can check whether it would be call 14
// (i.e. read byte) and, if so, whether the OS was about to
// issue a read byte call to a ROM despite being the tape
// FS being selected. If so then this is a get byte that
// we should service synthetically. Put the byte into Y
// and set A to zero to report that action was taken, then
// allow the PC read to return an RTS.
)
) {
uint8_t service_call = static_cast<uint8_t>(m6502_.get_value_of_register(CPU::MOS6502::Register::X));
if(address == 0xf0a8) {
if(!ram_[0x247] && service_call == 14) {
tape_.set_delegate(nullptr);
int cycles_left_while_plausibly_in_data = 50;
tape_.clear_interrupts(Interrupt::ReceiveDataFull);
while(!tape_.get_tape()->is_at_end()) {
tape_.run_for_input_pulse();
cycles_left_while_plausibly_in_data--;
if(!cycles_left_while_plausibly_in_data) fast_load_is_in_data_ = false;
if( (tape_.get_interrupt_status() & Interrupt::ReceiveDataFull) &&
(fast_load_is_in_data_ || tape_.get_data_register() == 0x2a)
) break;
}
tape_.set_delegate(this);
tape_.clear_interrupts(Interrupt::ReceiveDataFull);
interrupt_status_ |= tape_.get_interrupt_status();
fast_load_is_in_data_ = true;
m6502_.set_value_of_register(CPU::MOS6502::Register::A, 0);
m6502_.set_value_of_register(CPU::MOS6502::Register::Y, tape_.get_data_register());
*value = 0x60; // 0x60 is RTS
}
else *value = os_[address & 16383];
}
else *value = 0xea;
} else {
*value = os_[address & 16383];
}
}
} else {
if(isReadOperation(operation)) {
*value = roms_[active_rom_][address & 16383];
if(keyboard_is_active_) {
*value &= 0xf0;
for(int address_line = 0; address_line < 14; address_line++) {
if(!(address&(1 << address_line))) *value |= key_states_[address_line];
}
}
if(basic_is_active_) {
*value &= roms_[static_cast<int>(ROM::BASIC)][address & 16383];
}
} else if(rom_write_masks_[active_rom_]) {
roms_[active_rom_][address & 16383] = *value;
}
}
break;
}
}
cycles_since_display_update_ += Cycles(static_cast<int>(cycles));
cycles_since_audio_update_ += Cycles(static_cast<int>(cycles));
if(cycles_since_audio_update_ > Cycles(16384)) update_audio();
tape_.run_for(Cycles(static_cast<int>(cycles)));
cycles_until_display_interrupt_ -= cycles;
if(cycles_until_display_interrupt_ < 0) {
signal_interrupt(next_display_interrupt_);
update_display();
queue_next_display_interrupt();
}
if(typer_) typer_->run_for(Cycles(static_cast<int>(cycles)));
if(plus3_) plus3_->run_for(Cycles(4*static_cast<int>(cycles)));
if(shift_restart_counter_) {
shift_restart_counter_ -= cycles;
if(shift_restart_counter_ <= 0) {
shift_restart_counter_ = 0;
m6502_.set_power_on(true);
set_key_state(KeyShift, true);
is_holding_shift_ = true;
}
}
return Cycles(static_cast<int>(cycles));
}
forceinline void flush() {
update_display();
update_audio();
audio_queue_.perform();
}
void setup_output(float aspect_ratio) override final {
video_output_.reset(new VideoOutput(ram_));
}
void close_output() override final {
video_output_.reset();
}
Outputs::CRT::CRT *get_crt() override final {
return video_output_->get_crt();
}
Outputs::Speaker::Speaker *get_speaker() override final {
return &speaker_;
}
void run_for(const Cycles cycles) override final {
m6502_.run_for(cycles);
}
void tape_did_change_interrupt_status(Tape *tape) override final {
interrupt_status_ = (interrupt_status_ & ~(Interrupt::TransmitDataEmpty | Interrupt::ReceiveDataFull | Interrupt::HighToneDetect)) | tape_.get_interrupt_status();
evaluate_interrupts();
}
HalfCycles get_typer_delay() override final {
return m6502_.get_is_resetting() ? Cycles(625*25*128) : Cycles(0); // wait one second if resetting
}
HalfCycles get_typer_frequency() override final {
return Cycles(625*128*2); // accept a new character every two frames
}
void type_string(const std::string &string) override final {
std::unique_ptr<CharacterMapper> mapper(new CharacterMapper());
Utility::TypeRecipient::add_typer(string, std::move(mapper));
}
KeyboardMapper *get_keyboard_mapper() override {
return &keyboard_mapper_;
}
// MARK: - Configuration options.
std::vector<std::unique_ptr<Configurable::Option>> get_options() override {
return Electron::get_options();
}
void set_selections(const Configurable::SelectionSet &selections_by_option) override {
bool quickload;
if(Configurable::get_quick_load_tape(selections_by_option, quickload)) {
allow_fast_tape_hack_ = quickload;
set_use_fast_tape_hack();
}
Configurable::Display display;
if(Configurable::get_display(selections_by_option, display)) {
set_video_signal_configurable(display);
}
}
Configurable::SelectionSet get_accurate_selections() override {
Configurable::SelectionSet selection_set;
Configurable::append_quick_load_tape_selection(selection_set, false);
Configurable::append_display_selection(selection_set, Configurable::Display::Composite);
return selection_set;
}
Configurable::SelectionSet get_user_friendly_selections() override {
Configurable::SelectionSet selection_set;
Configurable::append_quick_load_tape_selection(selection_set, true);
Configurable::append_display_selection(selection_set, Configurable::Display::RGB);
return selection_set;
}
// MARK: - Activity Source
void set_activity_observer(Activity::Observer *observer) override {
activity_observer_ = observer;
if(activity_observer_) {
activity_observer_->register_led(caps_led);
activity_observer_->set_led_status(caps_led, caps_led_state_);
if(plus3_) {
plus3_->set_activity_observer(observer);
}
}
}
private:
enum class ROM {
Slot0 = 0,
Slot1, Slot2, Slot3,
Slot4, Slot5, Slot6, Slot7,
Keyboard = 8, Slot9,
BASIC = 10, Slot11,
Slot12, Slot13, Slot14, Slot15,
OS, DFS,
ADFS1, ADFS2
};
/*!
Sets the contents of @c slot to @c data. If @c is_writeable is @c true then writing to the slot
is enabled: it acts as if it were sideways RAM. Otherwise the slot is modelled as containing ROM.
*/
void set_rom(ROM slot, const std::vector<uint8_t> &data, bool is_writeable) {
uint8_t *target = nullptr;
switch(slot) {
case ROM::DFS: dfs_ = data; return;
case ROM::ADFS1: adfs1_ = data; return;
case ROM::ADFS2: adfs2_ = data; return;
case ROM::OS: target = os_; break;
default:
target = roms_[static_cast<int>(slot)];
rom_write_masks_[static_cast<int>(slot)] = is_writeable;
break;
}
// Copy in, with mirroring.
std::size_t rom_ptr = 0;
while(rom_ptr < 16384) {
std::size_t size_to_copy = std::min(16384 - rom_ptr, data.size());
std::memcpy(&target[rom_ptr], data.data(), size_to_copy);
rom_ptr += size_to_copy;
}
if(static_cast<int>(slot) < 16)
rom_inserted_[static_cast<int>(slot)] = true;
}
// MARK: - Work deferral updates.
inline void update_display() {
if(cycles_since_display_update_ > 0) {
video_output_->run_for(cycles_since_display_update_.flush());
}
}
inline void queue_next_display_interrupt() {
VideoOutput::Interrupt next_interrupt = video_output_->get_next_interrupt();
cycles_until_display_interrupt_ = next_interrupt.cycles;
next_display_interrupt_ = next_interrupt.interrupt;
}
inline void update_audio() {
speaker_.run_for(audio_queue_, cycles_since_audio_update_.divide(Cycles(SoundGenerator::clock_rate_divider)));
}
inline void signal_interrupt(Interrupt interrupt) {
interrupt_status_ |= interrupt;
evaluate_interrupts();
}
inline void clear_interrupt(Interrupt interrupt) {
interrupt_status_ &= ~interrupt;
evaluate_interrupts();
}
inline void evaluate_interrupts() {
if(interrupt_status_ & interrupt_control_) {
interrupt_status_ |= 1;
} else {
interrupt_status_ &= ~1;
}
m6502_.set_irq_line(interrupt_status_ & 1);
}
CPU::MOS6502::Processor<CPU::MOS6502::Personality::P6502, ConcreteMachine, false> m6502_;
// Things that directly constitute the memory map.
uint8_t roms_[16][16384];
bool rom_inserted_[16] = {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false};
bool rom_write_masks_[16] = {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false};
uint8_t os_[16384], ram_[32768];
std::vector<uint8_t> dfs_, adfs1_, adfs2_;
// Paging
int active_rom_ = static_cast<int>(ROM::Slot0);
bool keyboard_is_active_ = false;
bool basic_is_active_ = false;
// Interrupt and keyboard state
uint8_t interrupt_status_ = Interrupt::PowerOnReset | Interrupt::TransmitDataEmpty | 0x80;
uint8_t interrupt_control_ = 0;
uint8_t key_states_[14];
Electron::KeyboardMapper keyboard_mapper_;
// Counters related to simultaneous subsystems
Cycles cycles_since_display_update_ = 0;
Cycles cycles_since_audio_update_ = 0;
int cycles_until_display_interrupt_ = 0;
Interrupt next_display_interrupt_ = Interrupt::RealTimeClock;
VideoOutput::Range video_access_range_ = {0, 0xffff};
// Tape
Tape tape_;
bool use_fast_tape_hack_ = false;
bool allow_fast_tape_hack_ = false;
void set_use_fast_tape_hack() {
use_fast_tape_hack_ = allow_fast_tape_hack_ && tape_.has_tape();
}
bool fast_load_is_in_data_ = false;
// Disk
std::unique_ptr<Plus3> plus3_;
bool is_holding_shift_ = false;
int shift_restart_counter_ = 0;
// Outputs
std::unique_ptr<VideoOutput> video_output_;
Concurrency::DeferringAsyncTaskQueue audio_queue_;
SoundGenerator sound_generator_;
Outputs::Speaker::LowpassSpeaker<SoundGenerator> speaker_;
bool speaker_is_enabled_ = false;
// MARK: - Caps Lock status and the activity observer.
const std::string caps_led = "CAPS";
bool caps_led_state_ = false;
Activity::Observer *activity_observer_ = nullptr;
};
}
using namespace Electron;
Machine *Machine::Electron(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
using Target = Analyser::Static::Acorn::Target;
const Target *const acorn_target = dynamic_cast<const Target *>(target);
return new Electron::ConcreteMachine(*acorn_target, rom_fetcher);
}
Machine::~Machine() {}