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555 lines
15 KiB
C++
555 lines
15 KiB
C++
//
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// InputOutputController.h
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// Clock Signal
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//
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// Created by Thomas Harte on 20/03/2024.
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// Copyright © 2024 Thomas Harte. All rights reserved.
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//
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#pragma once
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#include "CMOSRAM.hpp"
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#include "FloppyDisc.hpp"
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#include "Keyboard.hpp"
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#include "Sound.hpp"
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#include "Video.hpp"
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#include "../../../Outputs/Log.hpp"
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#include "../../../Activity/Observer.hpp"
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namespace Archimedes {
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// IRQ A flags
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namespace IRQA {
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static constexpr uint8_t PrinterBusy = 0x01;
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static constexpr uint8_t SerialRinging = 0x02;
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static constexpr uint8_t PrinterAcknowledge = 0x04;
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static constexpr uint8_t VerticalFlyback = 0x08;
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static constexpr uint8_t PowerOnReset = 0x10;
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static constexpr uint8_t Timer0 = 0x20;
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static constexpr uint8_t Timer1 = 0x40;
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static constexpr uint8_t Force = 0x80;
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}
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// IRQ B flags
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namespace IRQB {
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static constexpr uint8_t PoduleFIQRequest = 0x01;
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static constexpr uint8_t SoundBufferPointerUsed = 0x02;
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static constexpr uint8_t SerialLine = 0x04;
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static constexpr uint8_t IDE = 0x08;
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static constexpr uint8_t FloppyDiscChanged = 0x10;
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static constexpr uint8_t PoduleIRQRequest = 0x20;
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static constexpr uint8_t KeyboardTransmitEmpty = 0x40;
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static constexpr uint8_t KeyboardReceiveFull = 0x80;
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}
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// FIQ flags
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namespace FIQ {
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static constexpr uint8_t FloppyDiscData = 0x01;
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static constexpr uint8_t FloppyDiscInterrupt = 0x02;
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static constexpr uint8_t Econet = 0x04;
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static constexpr uint8_t PoduleFIQRequest = 0x40;
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static constexpr uint8_t Force = 0x80;
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}
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namespace InterruptRequests {
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static constexpr int IRQ = 0x01;
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static constexpr int FIQ = 0x02;
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};
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template <typename InterruptObserverT, typename ClockRateObserverT>
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struct InputOutputController {
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int interrupt_mask() const {
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return
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((irq_a_.request() | irq_b_.request()) ? InterruptRequests::IRQ : 0) |
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(fiq_.request() ? InterruptRequests::FIQ : 0);
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}
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template <int c>
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bool tick_timer() {
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if(!counters_[c].value && !counters_[c].reload) {
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return false;
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}
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--counters_[c].value;
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if(!counters_[c].value) {
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counters_[c].value = counters_[c].reload;
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switch(c) {
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case 0: return irq_a_.set(IRQA::Timer0);
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case 1: return irq_a_.set(IRQA::Timer1);
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case 3: {
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serial_.shift();
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keyboard_.update();
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const uint8_t events = serial_.events(IOCParty);
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bool did_interrupt = false;
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if(events & HalfDuplexSerial::Receive) {
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did_interrupt |= irq_b_.set(IRQB::KeyboardReceiveFull);
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}
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if(events & HalfDuplexSerial::Transmit) {
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did_interrupt |= irq_b_.set(IRQB::KeyboardTransmitEmpty);
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}
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return did_interrupt;
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}
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default: break;
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}
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// TODO: events for timers 2 (baud).
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}
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return false;
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}
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void tick_timers() {
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bool did_change_interrupts = false;
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did_change_interrupts |= tick_timer<0>();
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did_change_interrupts |= tick_timer<1>();
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did_change_interrupts |= tick_timer<2>();
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did_change_interrupts |= tick_timer<3>();
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if(did_change_interrupts) {
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observer_.update_interrupts();
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}
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}
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void tick_floppy() {
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floppy_.run_for(Cycles(1));
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}
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void set_disk(std::shared_ptr<Storage::Disk::Disk> disk, size_t drive) {
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floppy_.set_disk(disk, drive);
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}
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/// Decomposes an Archimedes bus address into bank, offset and type.
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struct Address {
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constexpr Address(uint32_t bus_address) noexcept {
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bank = (bus_address >> 16) & 0b111;
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type = Type((bus_address >> 19) & 0b11);
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offset = bus_address & 0b1111100;
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}
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/// A value from 0 to 7 indicating the device being addressed.
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uint32_t bank;
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/// A seven-bit value which is a multiple of 4, indicating the address within the bank.
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uint32_t offset;
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/// Access type.
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enum class Type {
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Sync = 0b00,
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Fast = 0b10,
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Medium = 0b01,
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Slow = 0b11
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} type;
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};
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// Peripheral addresses on the A500:
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//
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// fast/1 = FDC
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// sync/2 = econet
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// sync/3 = serial line
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//
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// bank 4 = podules
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//
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// fast/5
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template <typename IntT>
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bool read(uint32_t address, IntT &destination) {
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const Address target(address);
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const auto set_byte = [&](uint8_t value) {
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if constexpr (std::is_same_v<IntT, uint32_t>) {
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destination = static_cast<uint32_t>(value << 16) | 0xff'00'ff'ff;
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} else {
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destination = value;
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}
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};
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// TODO: flatten the switch below, and the equivalent in `write`.
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switch(target.bank) {
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default:
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logger.error().append("Unrecognised IOC read from %08x i.e. bank %d / type %d", address, target.bank, target.type);
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destination = IntT(~0);
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break;
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// Bank 0: internal registers.
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case 0:
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switch(target.offset) {
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default:
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logger.error().append("Unrecognised IOC bank 0 read; offset %02x", target.offset);
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break;
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case 0x00: {
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uint8_t value = control_ | 0xc0;
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value &= ~(i2c_.clock() ? 2 : 0);
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value &= ~(i2c_.data() ? 1 : 0);
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set_byte(value);
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// logger.error().append("IOC control read: C:%d D:%d", !(value & 2), !(value & 1));
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} break;
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case 0x04:
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set_byte(serial_.input(IOCParty));
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irq_b_.clear(IRQB::KeyboardReceiveFull);
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observer_.update_interrupts();
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// logger.error().append("IOC keyboard receive: %02x", value);
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break;
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// IRQ A.
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case 0x10:
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set_byte(irq_a_.status);
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// logger.error().append("IRQ A status is %02x", value);
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break;
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case 0x14:
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set_byte(irq_a_.request());
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// logger.error().append("IRQ A request is %02x", value);
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break;
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case 0x18:
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set_byte(irq_a_.mask);
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// logger.error().append("IRQ A mask is %02x", value);
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break;
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// IRQ B.
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case 0x20:
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set_byte(irq_b_.status);
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// logger.error().append("IRQ B status is %02x", value);
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break;
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case 0x24:
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set_byte(irq_b_.request());
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// logger.error().append("IRQ B request is %02x", value);
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break;
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case 0x28:
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set_byte(irq_b_.mask);
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// logger.error().append("IRQ B mask is %02x", value);
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break;
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// FIQ.
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case 0x30:
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set_byte(fiq_.status);
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logger.error().append("FIQ status is %02x", fiq_.status);
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break;
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case 0x34:
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set_byte(fiq_.request());
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logger.error().append("FIQ request is %02x", fiq_.request());
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break;
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case 0x38:
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set_byte(fiq_.mask);
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logger.error().append("FIQ mask is %02x", fiq_.mask);
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break;
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// Counters.
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case 0x40: case 0x50: case 0x60: case 0x70:
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set_byte(counters_[(target.offset >> 4) - 0x4].output & 0xff);
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// logger.error().append("%02x: Counter %d low is %02x", target, (target >> 4) - 0x4, value);
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break;
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case 0x44: case 0x54: case 0x64: case 0x74:
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set_byte(counters_[(target.offset >> 4) - 0x4].output >> 8);
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// logger.error().append("%02x: Counter %d high is %02x", target, (target >> 4) - 0x4, value);
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break;
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}
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break;
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// Bank 1: the floppy disc controller.
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case 1:
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set_byte(floppy_.read(target.offset >> 2));
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// logger.error().append("Floppy read; offset %02x", target.offset);
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break;
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}
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return true;
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}
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template <typename IntT>
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bool write(uint32_t address, IntT bus_value) {
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const Address target(address);
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// Empirically, RISC OS 3.19:
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// * at 03801e88 and 03801e8c loads R8 and R9 with 0xbe0000 and 0xff0000 respectively; and
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// * subsequently uses 32-bit strs (e.g. at 03801eac) to write those values to latch A.
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//
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// Given that 8-bit ARM writes duplicate the 8-bit value four times across the data bus,
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// my conclusion is that the IOC is probably connected to data lines 15–23.
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//
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// Hence: use @c byte to get a current 8-bit value.
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const auto byte = [](IntT original) -> uint8_t {
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if constexpr (std::is_same_v<IntT, uint32_t>) {
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return static_cast<uint8_t>(original >> 16);
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} else {
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return original;
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}
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};
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switch(target.bank) {
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default:
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logger.error().append("Unrecognised IOC write of %02x to %08x i.e. bank %d / type %d", bus_value, address, target.bank, target.type);
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break;
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// Bank 0: internal registers.
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case 0:
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switch(target.offset) {
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default:
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logger.error().append("Unrecognised IOC bank 0 write; %02x to offset %02x", bus_value, target.offset);
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break;
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case 0x00:
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control_ = byte(bus_value);
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i2c_.set_clock_data(!(bus_value & 2), !(bus_value & 1));
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// Per the A500 documentation:
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// b7: vertical sync/test input bit, so should be programmed high;
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// b6: input for printer acknowledgement, so should be programmed high;
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// b5: speaker mute; 1 = muted;
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// b4: "Available on the auxiliary I/O connector"
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// b3: "Programmed HIGH, unless Reset Mask is required."
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// b2: Used as the floppy disk (READY) input and must be programmed high;
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// b1 and b0: I2C connections as above.
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break;
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case 0x04:
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serial_.output(IOCParty, byte(bus_value));
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irq_b_.clear(IRQB::KeyboardTransmitEmpty);
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observer_.update_interrupts();
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break;
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case 0x14:
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// b2: clear IF.
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// b3: clear IR.
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// b4: clear POR.
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// b5: clear TM[0].
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// b6: clear TM[1].
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irq_a_.clear(byte(bus_value) & 0x7c);
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observer_.update_interrupts();
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break;
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// Interrupts.
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case 0x18:
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irq_a_.mask = byte(bus_value);
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logger.error().append("IRQ A mask set to %02x", byte(bus_value));
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break;
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case 0x28:
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irq_b_.mask = byte(bus_value);
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logger.error().append("IRQ B mask set to %02x", byte(bus_value));
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break;
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case 0x38:
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fiq_.mask = byte(bus_value);
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logger.error().append("FIQ mask set to %02x", byte(bus_value));
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break;
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// Counters.
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case 0x40: case 0x50: case 0x60: case 0x70:
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counters_[(target.offset >> 4) - 0x4].reload = uint16_t(
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(counters_[(target.offset >> 4) - 0x4].reload & 0xff00) | byte(bus_value)
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);
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break;
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case 0x44: case 0x54: case 0x64: case 0x74:
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counters_[(target.offset >> 4) - 0x4].reload = uint16_t(
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(counters_[(target.offset >> 4) - 0x4].reload & 0x00ff) | (byte(bus_value) << 8)
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);
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break;
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case 0x48: case 0x58: case 0x68: case 0x78:
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counters_[(target.offset >> 4) - 0x4].value = counters_[(target.offset >> 4) - 0x4].reload;
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break;
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case 0x4c: case 0x5c: case 0x6c: case 0x7c:
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counters_[(target.offset >> 4) - 0x4].output = counters_[(target.offset >> 4) - 0x4].value;
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break;
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}
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break;
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// Bank 1: the floppy disc controller.
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case 1:
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// logger.error().append("Floppy write; %02x to offset %02x", bus_value, target.offset);
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floppy_.write(target.offset >> 2, byte(bus_value));
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// set_byte(floppy_.read(target.offset >> 2));
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break;
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// Bank 5: both the hard disk and the latches, depending on type.
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case 5:
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switch(target.type) {
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default:
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logger.error().append("Unrecognised IOC bank 5 type %d write; %02x to offset %02x", target.type, bus_value, target.offset);
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break;
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case Address::Type::Fast:
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switch(target.offset) {
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default:
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logger.error().append("Unrecognised IOC fast bank 5 write; %02x to offset %02x", bus_value, target.offset);
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break;
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case 0x00:
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logger.error().append("TODO: printer data write; %02x", byte(bus_value));
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break;
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case 0x18: {
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// TODO, per the A500 documentation:
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//
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// Latch B:
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// b0: ?
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// b1: double/single density; 0 = double.
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// b2: ?
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// b3: floppy drive reset; 0 = reset.
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// b4: printer strobe
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// b5: ?
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// b6: ?
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// b7: Head select 3?
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const uint8_t value = byte(bus_value);
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floppy_.set_is_double_density(!(value & 0x2));
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if(value & 0x08) floppy_.reset();
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// logger.error().append("TODO: latch B write; %02x", byte(bus_value));
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} break;
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case 0x40: {
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const uint8_t value = byte(bus_value);
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floppy_.set_control(value);
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// Set the floppy indicator on if any drive is selected,
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// because this emulator is compressing them all into a
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// single LED, and the machine has indicated 'in use'.
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if(activity_observer_) {
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activity_observer_->set_led_status(FloppyActivityLED,
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!(value & 0x40) && ((value & 0xf) != 0xf)
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);
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}
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} break;
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case 0x48:
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// TODO, per the A500 documentation:
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//
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// Latch C:
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// (probably not present on earlier machines?)
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// b2/b3: sync polarity [b3 = V polarity, b2 = H?]
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// b0/b1: VIDC master clock; 00 = 24Mhz, 01 = 25.175Mhz; 10 = 36Mhz; 11 = reserved.
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logger.error().append("TODO: latch C write; %02x", byte(bus_value));
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break;
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}
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break;
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}
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break;
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}
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// case 0x327'0000 & AddressMask: // Bank 7
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// logger.error().append("TODO: exteded external podule space");
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// return true;
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//
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// case 0x336'0000 & AddressMask:
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// logger.error().append("TODO: podule interrupt request");
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// return true;
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//
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// case 0x336'0004 & AddressMask:
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// logger.error().append("TODO: podule interrupt mask");
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// return true;
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//
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// case 0x33a'0000 & AddressMask:
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// logger.error().append("TODO: 6854 / econet write");
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// return true;
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//
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// case 0x33b'0000 & AddressMask:
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// logger.error().append("TODO: 6551 / serial line write");
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// return true;
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return true;
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}
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InputOutputController(InterruptObserverT &observer, ClockRateObserverT &clock_observer, const uint8_t *ram) :
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observer_(observer),
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keyboard_(serial_),
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floppy_(*this),
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sound_(*this, ram),
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video_(*this, clock_observer, sound_, ram)
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{
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irq_a_.status = IRQA::Force | IRQA::PowerOnReset;
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irq_b_.status = 0x00;
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fiq_.status = FIQ::Force;
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i2c_.add_peripheral(&cmos_, 0xa0);
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update_interrupts();
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}
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auto &sound() { return sound_; }
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const auto &sound() const { return sound_; }
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auto &video() { return video_; }
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const auto &video() const { return video_; }
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auto &keyboard() { return keyboard_; }
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const auto &keyboard() const { return keyboard_; }
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void update_interrupts() {
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const auto set = [&](Interrupt &target, uint8_t flag, bool set) {
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if(set) {
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target.set(flag);
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} else {
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target.clear(flag);
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}
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};
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set(irq_b_, IRQB::SoundBufferPointerUsed, sound_.interrupt());
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set(fiq_, FIQ::FloppyDiscInterrupt, floppy_.get_interrupt_request_line());
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set(fiq_, FIQ::FloppyDiscData, floppy_.get_data_request_line());
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if(video_.interrupt()) {
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irq_a_.set(IRQA::VerticalFlyback);
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}
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observer_.update_interrupts();
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}
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void set_activity_observer(Activity::Observer *observer) {
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activity_observer_ = observer;
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if(activity_observer_) {
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activity_observer_->register_led(FloppyActivityLED);
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}
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}
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private:
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Log::Logger<Log::Source::ARMIOC> logger;
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InterruptObserverT &observer_;
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Activity::Observer *activity_observer_ = nullptr;
|
||
static inline const std::string FloppyActivityLED = "Drive";
|
||
|
||
// IRQA, IRQB and FIQ states.
|
||
struct Interrupt {
|
||
uint8_t status = 0x00, mask = 0x00;
|
||
uint8_t request() const {
|
||
return status & mask;
|
||
}
|
||
bool set(uint8_t value) {
|
||
status |= value;
|
||
return status & mask;
|
||
}
|
||
void clear(uint8_t bits) {
|
||
status &= ~bits;
|
||
}
|
||
};
|
||
Interrupt irq_a_, irq_b_, fiq_;
|
||
|
||
// The IOCs four counters.
|
||
struct Counter {
|
||
uint16_t value = 0;
|
||
uint16_t reload = 0;
|
||
uint16_t output = 0;
|
||
};
|
||
Counter counters_[4];
|
||
|
||
// The KART and keyboard beyond it.
|
||
HalfDuplexSerial serial_;
|
||
Keyboard keyboard_;
|
||
|
||
// The control register.
|
||
uint8_t control_ = 0xff;
|
||
|
||
// The floppy disc interface.
|
||
FloppyDisc<InputOutputController> floppy_;
|
||
|
||
// The I2C bus.
|
||
I2C::Bus i2c_;
|
||
CMOSRAM cmos_;
|
||
|
||
// Audio and video.
|
||
Sound<InputOutputController> sound_;
|
||
Video<InputOutputController, ClockRateObserverT, Sound<InputOutputController>> video_;
|
||
};
|
||
|
||
}
|
||
|