// // 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 "../MachineTypes.hpp" #include "../../Configurable/Configurable.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/MassStorage/SCSI/SCSI.hpp" #include "../../Storage/MassStorage/SCSI/DirectAccessDevice.hpp" #include "../../Storage/Tape/Tape.hpp" #include "../Utility/Typer.hpp" #include "../../Analyser/Static/Acorn/Target.hpp" #include "../../ClockReceiver/JustInTime.hpp" #include "Interrupts.hpp" #include "Keyboard.hpp" #include "Plus3.hpp" #include "SoundGenerator.hpp" #include "Tape.hpp" #include "Video.hpp" namespace Electron { template class ConcreteMachine: public Machine, public MachineTypes::TimedMachine, public MachineTypes::ScanProducer, public MachineTypes::AudioProducer, public MachineTypes::MediaTarget, public MachineTypes::MappedKeyboardMachine, public Configurable::Device, public CPU::MOS6502::BusHandler, public Tape::Delegate, public Utility::TypeRecipient, public Activity::Source, public SCSI::Bus::Observer, public ClockingHint::Observer { public: ConcreteMachine(const Analyser::Static::Acorn::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) : m6502_(*this), scsi_bus_(4'000'000), hard_drive_(scsi_bus_, 0), scsi_device_(scsi_bus_.add_device()), video_(ram_), 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); speaker_.set_high_frequency_cutoff(6000); ::ROM::Request request = ::ROM::Request(::ROM::Name::AcornBASICII) && ::ROM::Request(::ROM::Name::AcornElectronMOS100); if(target.has_pres_adfs) { request = request && ::ROM::Request(::ROM::Name::PRESADFSSlot1) && ::ROM::Request(::ROM::Name::PRESADFSSlot2); } if(target.has_acorn_adfs) { request = request && ::ROM::Request(::ROM::Name::AcornADFS); } if(target.has_dfs) { request = request && ::ROM::Request(::ROM::Name::Acorn1770DFS); } if(target.has_ap6_rom) { request = request && ::ROM::Request(::ROM::Name::PRESAdvancedPlus6); } auto roms = rom_fetcher(request); if(!request.validate(roms)) { throw ROMMachine::Error::MissingROMs; } set_rom(ROM::BASIC, roms.find(::ROM::Name::AcornBASICII)->second, false); set_rom(ROM::OS, roms.find(::ROM::Name::AcornElectronMOS100)->second, false); /* ROM slot mapping applied: * the keyboard and BASIC ROMs occupy slots 8, 9, 10 and 11; * the DFS, if in use, occupies slot 1; * the Pres ADFS, if in use, occupies slots 4 and 5; * the Acorn ADFS, if in use, occupies slot 6; * the AP6, if in use, occupies slot 15; and * if sideways RAM was asked for, all otherwise unused slots are populated with sideways RAM. */ if(target.has_dfs || target.has_acorn_adfs || target.has_pres_adfs) { plus3_ = std::make_unique(); if(target.has_dfs) { set_rom(ROM::Slot0, roms.find(::ROM::Name::Acorn1770DFS)->second, true); } if(target.has_pres_adfs) { set_rom(ROM::Slot4, roms.find(::ROM::Name::PRESADFSSlot1)->second, true); set_rom(ROM::Slot5, roms.find(::ROM::Name::PRESADFSSlot2)->second, true); } if(target.has_acorn_adfs) { set_rom(ROM::Slot6, roms.find(::ROM::Name::AcornADFS)->second, true); } } if(target.has_ap6_rom) { set_rom(ROM::Slot15, roms.find(::ROM::Name::PRESAdvancedPlus6)->second, true); } if(target.has_sideways_ram) { for(int c = 0; c < 16; c++) { if(rom_inserted_[c]) continue; if(c >= int(ROM::Keyboard) && c < int(ROM::BASIC)+1) continue; set_sideways_ram(ROM(c)); } } insert_media(target.media); if(!target.loading_command.empty()) { type_string(target.loading_command); } if(target.should_shift_restart) { shift_restart_counter_ = 1000000; } if(has_scsi_bus) { scsi_bus_.add_observer(this); scsi_bus_.set_clocking_hint_observer(this); } } ~ConcreteMachine() { audio_queue_.flush(); } void set_key_state(uint16_t key, bool isPressed) final { switch(key) { default: if(isPressed) key_states_[key >> 4] |= key&0xf; else key_states_[key >> 4] &= ~(key&0xf); break; case KeyBreak: m6502_.set_reset_line(isPressed); break; #define FuncShiftedKey(source, dest) \ case source: \ set_key_state(KeyFunc, isPressed); \ set_key_state(dest, isPressed); \ break; FuncShiftedKey(KeyF1, Key1); FuncShiftedKey(KeyF2, Key2); FuncShiftedKey(KeyF3, Key3); FuncShiftedKey(KeyF4, Key4); FuncShiftedKey(KeyF5, Key5); FuncShiftedKey(KeyF6, Key6); FuncShiftedKey(KeyF7, Key7); FuncShiftedKey(KeyF8, Key8); FuncShiftedKey(KeyF9, Key9); FuncShiftedKey(KeyF0, Key0); #undef FuncShiftedKey } } void clear_all_keys() 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) 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 cartridge : media.cartridges) { const ROM first_slot_tried = slot; while(rom_inserted_[int(slot)]) { slot = ROM((int(slot) + 1) & 15); if(slot == first_slot_tried) return false; } set_rom(slot, cartridge->get_segments().front().data, false); } // TODO: allow this only at machine startup? if(!media.mass_storage_devices.empty()) { hard_drive_->set_storage(media.mass_storage_devices.front()); } return !media.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) { video_.flush(); } 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_.last_valid()->get_cycles_until_next_ram_availability(video_.time_since_flush().template as() + 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_); } [[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)) { video_->write(address, *value); video_access_range_ = video_.last_valid()->get_memory_access_range(); } 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 } else { // 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_->read(address); else plus3_->write(address, *value); } break; case 0xfc00: if(plus3_ && (address&0x00f0) == 0x00c0) { if(!isReadOperation(operation)) { plus3_->set_control_register(*value); } else *value = 1; } if(has_scsi_bus && (address&0x00f0) == 0x0040) { scsi_acknowledge_ = true; if(!isReadOperation(operation)) { scsi_data_ = *value; push_scsi_output(); } else { *value = SCSI::data_lines(scsi_bus_.get_state()); push_scsi_output(); } } break; case 0xfc03: if(has_scsi_bus && (address&0x00f0) == 0x0040) { scsi_interrupt_state_ = false; scsi_interrupt_mask_ = *value & 1; evaluate_interrupts(); } break; case 0xfc01: if(has_scsi_bus && (address&0x00f0) == 0x0040 && isReadOperation(operation)) { // Status byte is: // // b7: SCSI C/D // b6: SCSI I/O // b5: SCSI REQ // b4: interrupt flag // b3: 0 // b2: 0 // b1: SCSI BSY // b0: SCSI MSG const auto state = scsi_bus_.get_state(); *value = (state & SCSI::Line::Control ? 0x80 : 0x00) | (state & SCSI::Line::Input ? 0x40 : 0x00) | (state & SCSI::Line::Request ? 0x20 : 0x00) | ((scsi_interrupt_state_ && scsi_interrupt_mask_) ? 0x10 : 0x00) | (state & SCSI::Line::Busy ? 0x02 : 0x00) | (state & SCSI::Line::Message ? 0x01 : 0x00); // Empirical guess: this is also the trigger to affect busy/request/acknowledge // signalling. Maybe? if(scsi_select_ && scsi_bus_.get_state() & SCSI::Line::Busy) { scsi_select_ = false; push_scsi_output(); } } break; case 0xfc02: if(has_scsi_bus && (address&0x00f0) == 0x0040) { scsi_select_ = true; push_scsi_output(); } break; // SCSI locations: // // fc40: data, read and write // fc41: status read // fc42: select write // fc43: interrupt latch // // // Interrupt latch is: // // b0: enable or disable IRQ on REQ // (and, possibly, writing to the latch acknowledges?) 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 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. ) ) { const auto service_call = uint8_t(m6502_.value_of(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(CPU::MOS6502::Register::A, 0); m6502_.set_value_of(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_[int(ROM::BASIC)][address & 16383]; } } else if(rom_write_masks_[active_rom_]) { roms_[active_rom_][address & 16383] = *value; } } break; } } if(video_ += Cycles(int(cycles))) { signal_interrupt(video_.last_valid()->get_interrupts()); } cycles_since_audio_update_ += Cycles(int(cycles)); if(cycles_since_audio_update_ > Cycles(16384)) update_audio(); tape_.run_for(Cycles(int(cycles))); if(typer_) typer_->run_for(Cycles(int(cycles))); if(plus3_) plus3_->run_for(Cycles(4*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; } } if constexpr (has_scsi_bus) { if(scsi_is_clocked_) { scsi_bus_.run_for(Cycles(int(cycles))); } } return Cycles(int(cycles)); } void flush_output(int outputs) final { if(outputs & Output::Video) { video_.flush(); } if(outputs & Output::Audio) { update_audio(); audio_queue_.perform(); } } void set_scan_target(Outputs::Display::ScanTarget *scan_target) final { video_.last_valid()->set_scan_target(scan_target); } Outputs::Display::ScanStatus get_scaled_scan_status() const final { return video_.last_valid()->get_scaled_scan_status(); } void set_display_type(Outputs::Display::DisplayType display_type) final { video_.last_valid()->set_display_type(display_type); } Outputs::Display::DisplayType get_display_type() const final { return video_.last_valid()->get_display_type(); } Outputs::Speaker::Speaker *get_speaker() final { return &speaker_; } void run_for(const Cycles cycles) final { m6502_.run_for(cycles); } void scsi_bus_did_change(SCSI::Bus *, SCSI::BusState new_state, double) final { // Release acknowledge when request is released. if(scsi_acknowledge_ && !(new_state & SCSI::Line::Request)) { scsi_acknowledge_ = false; push_scsi_output(); } // Output occurs only while SCSI::Line::Input is inactive; therefore a change // in that line affects what's on the bus. if(((new_state^previous_bus_state_)&SCSI::Line::Input)) { push_scsi_output(); } scsi_interrupt_state_ |= (new_state^previous_bus_state_)&new_state & SCSI::Line::Request; previous_bus_state_ = new_state; evaluate_interrupts(); } void set_component_prefers_clocking(ClockingHint::Source *, ClockingHint::Preference preference) final { scsi_is_clocked_ = preference != ClockingHint::Preference::None; } void tape_did_change_interrupt_status(Tape *) final { interrupt_status_ = (interrupt_status_ & ~(Interrupt::TransmitDataEmpty | Interrupt::ReceiveDataFull | Interrupt::HighToneDetect)) | tape_.get_interrupt_status(); evaluate_interrupts(); } HalfCycles get_typer_delay(const std::string &text) const final { if(!m6502_.get_is_resetting()) { return Cycles(0); } // Add a longer delay for a command at reset that involves pressing a modifier; // empirically this seems to be a requirement, in order to avoid a collision with // the system's built-in modifier-at-startup test (e.g. to perform shift+break). CharacterMapper test_mapper; const uint16_t *const sequence = test_mapper.sequence_for_character(text[0]); return is_modifier(Key(sequence[0])) ? Cycles(1'000'000) : Cycles(750'000); } HalfCycles get_typer_frequency() const final { return Cycles(60'000); } void type_string(const std::string &string) final { Utility::TypeRecipient::add_typer(string); } bool can_type(char c) const final { return Utility::TypeRecipient::can_type(c); } KeyboardMapper *get_keyboard_mapper() final { return &keyboard_mapper_; } // MARK: - Configuration options. std::unique_ptr get_options() final { auto options = std::make_unique(Configurable::OptionsType::UserFriendly); options->output = get_video_signal_configurable(); options->quickload = allow_fast_tape_hack_; return options; } void set_options(const std::unique_ptr &str) final { const auto options = dynamic_cast(str.get()); set_video_signal_configurable(options->output); allow_fast_tape_hack_ = options->quickload; set_use_fast_tape_hack(); } // MARK: - Activity Source void set_activity_observer(Activity::Observer *observer) final { activity_observer_ = observer; if(activity_observer_) { activity_observer_->register_led(caps_led, Activity::Observer::LEDPresentation::Persistent); activity_observer_->set_led_status(caps_led, caps_led_state_); } if(plus3_) { plus3_->set_activity_observer(observer); } if(has_scsi_bus) { scsi_bus_.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 &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_[int(slot)]; rom_write_masks_[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(int(slot) < 16) { rom_inserted_[int(slot)] = true; } } /*! Enables @c slot as sideways RAM; ensures that it does not currently contain a valid ROM signature. */ void set_sideways_ram(ROM slot) { std::memset(roms_[int(slot)], 0xff, 16*1024); if(int(slot) < 16) { rom_inserted_[int(slot)] = true; rom_write_masks_[int(slot)] = true; } } // MARK: - Work deferral updates. 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; } if constexpr (has_scsi_bus) { m6502_.set_irq_line((scsi_interrupt_state_ && scsi_interrupt_mask_) | (interrupt_status_ & 1)); } else { m6502_.set_irq_line(interrupt_status_ & 1); } } CPU::MOS6502::Processor 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 dfs_, adfs1_, adfs2_; // Paging int active_rom_ = 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_audio_update_ = 0; 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_; bool is_holding_shift_ = false; int shift_restart_counter_ = 0; // Hard drive. SCSI::Bus scsi_bus_; SCSI::Target::Target hard_drive_; SCSI::BusState previous_bus_state_ = SCSI::DefaultBusState; const size_t scsi_device_ = 0; uint8_t scsi_data_ = 0; bool scsi_select_ = false; bool scsi_acknowledge_ = false; bool scsi_is_clocked_ = false; bool scsi_interrupt_state_ = false; bool scsi_interrupt_mask_ = false; void push_scsi_output() { scsi_bus_.set_device_output(scsi_device_, (scsi_bus_.get_state()&SCSI::Line::Input ? 0 : scsi_data_) | (scsi_select_ ? SCSI::Line::SelectTarget : 0) | (scsi_acknowledge_ ? SCSI::Line::Acknowledge : 0) ); } // Outputs JustInTimeActor video_; Concurrency::AsyncTaskQueue audio_queue_; SoundGenerator sound_generator_; Outputs::Speaker::PullLowpass 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; std::unique_ptr 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(target); if(acorn_target->media.mass_storage_devices.empty()) { return std::make_unique>(*acorn_target, rom_fetcher); } else { return std::make_unique>(*acorn_target, rom_fetcher); } }