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Add enough of a keyboard to respond to reset.
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Thomas Harte
parent
18154278d1
commit
9d08282e28
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@ -71,6 +71,119 @@ static_assert(BitMask<15, 14>::value == 49152);
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namespace Archimedes {
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/// Models a half-duplex serial link between two parties, framing bytes with one start bit and two stop bits.
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struct HalfDuplexSerial {
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static constexpr uint16_t ShiftMask = 0b1111'1110'0000'0000;
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/// Enqueues @c value for output.
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void output(int party, uint8_t value) {
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parties_[party].output_count = 11;
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parties_[party].output = uint16_t((value << 1) | ShiftMask);
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}
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/// @returns The last observed input.
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uint8_t input(int party) const {
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return uint8_t(parties_[party].input >> 1);
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}
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static constexpr uint8_t Receive = 1 << 0;
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static constexpr uint8_t Transmit = 1 << 1;
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/// @returns A bitmask of events that occurred during the last shift.
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uint8_t events(int party) {
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const auto result = parties_[party].events;
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parties_[party].events = 0;
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return result;
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}
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bool is_outputting(int party) const {
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return parties_[party].output_count != 11;
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}
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/// Updates the shifters on both sides of the serial link.
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void shift() {
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const uint16_t next = parties_[0].output & parties_[1].output & 1;
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for(int c = 0; c < 2; c++) {
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if(parties_[c].output_count) {
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--parties_[c].output_count;
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if(!parties_[c].output_count) {
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parties_[c].events |= Transmit;
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parties_[c].input_count = -1;
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}
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parties_[c].output = (parties_[c].output >> 1) | ShiftMask;
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} else {
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// Check for a start bit.
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if(parties_[c].input_count == -1 && !next) {
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parties_[c].input_count = 0;
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}
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// Shift in if currently observing.
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if(parties_[c].input_count >= 0 && parties_[c].input_count < 11) {
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parties_[c].input = uint16_t((parties_[c].input >> 1) | (next << 10));
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++parties_[c].input_count;
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if(parties_[c].input_count == 11) {
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parties_[c].events |= Receive;
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parties_[c].input_count = -1;
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}
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}
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}
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}
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}
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private:
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struct Party {
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int output_count = 0;
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int input_count = -1;
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uint16_t output = 0xffff;
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uint16_t input = 0;
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uint8_t events = 0;
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} parties_[2];
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};
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static constexpr int IOCParty = 0;
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static constexpr int KeyboardParty = 1;
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// Resource for the keyboard protocol: https://github.com/tmk/tmk_keyboard/wiki/ACORN-ARCHIMEDES-Keyboard
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struct Keyboard {
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Keyboard(HalfDuplexSerial &serial) : serial_(serial) {}
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void update() {
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if(serial_.events(KeyboardParty) & HalfDuplexSerial::Receive) {
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const uint8_t input = serial_.input(KeyboardParty);
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switch(input) {
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case HRST:
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// TODO:
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case RAK1:
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case RAK2:
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serial_.output(KeyboardParty, input);
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break;
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default: break;
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}
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}
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}
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private:
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HalfDuplexSerial &serial_;
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static constexpr uint8_t HRST = 0b1111'1111; // Keyboard reset.
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static constexpr uint8_t RAK1 = 0b1111'1110; // Reset response #1.
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static constexpr uint8_t RAK2 = 0b1111'1101; // Reset response #2.
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static constexpr uint8_t RQID = 0b0010'0000; // Request for keyboard ID.
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static constexpr uint8_t RQMP = 0b0010'0010; // Request for mouse data.
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static constexpr uint8_t BACK = 0b0011'1111; // Acknowledge for first keyboard data byte pair.
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static constexpr uint8_t NACK = 0b0011'0000; // Acknowledge for last keyboard data byte pair, selects scan/mouse mode.
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static constexpr uint8_t SACK = 0b0011'0001; // Last data byte acknowledge.
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static constexpr uint8_t MACK = 0b0011'0010; // Last data byte acknowledge.
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static constexpr uint8_t SMAK = 0b0011'0011; // Last data byte acknowledge.
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static constexpr uint8_t PRST = 0b0010'0001; // Does nothing.
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};
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struct Video {
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void write(uint32_t value) {
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const auto target = (value >> 24) & 0xfc;
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@ -221,9 +334,24 @@ struct Interrupts {
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switch(c) {
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case 0: return irq_a_.apply(IRQA::Timer0);
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case 1: return irq_a_.apply(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_.apply(IRQB::KeyboardReceiveFull);
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}
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if(events & HalfDuplexSerial::Transmit) {
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did_interrupt |= irq_b_.apply(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) and 3 (the keyboard).
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// TODO: events for timers 2 (baud).
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}
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return false;
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@ -254,8 +382,8 @@ struct Interrupts {
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return true;
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case 0x3200004 & AddressMask:
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logger.error().append("TODO: IOC keyboard receive");
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value = 0;
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value = serial_.input(IOCParty);
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logger.error().append("IOC keyboard receive: %02x", value);
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return true;
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// IRQ A.
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@ -333,7 +461,8 @@ struct Interrupts {
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return true;
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case 0x320'0004 & AddressMask:
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logger.error().append("TODO: IOC keyboard transmit %02x", value);
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logger.error().append("IOC keyboard transmit %02x", value);
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serial_.output(IOCParty, value);
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return true;
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case 0x320'0014 & AddressMask:
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@ -427,7 +556,7 @@ struct Interrupts {
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return true;
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}
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Interrupts() {
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Interrupts() : keyboard_(serial_) {
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irq_a_.status = IRQA::SetAlways | IRQA::PowerOnReset;
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irq_b_.status = 0x00;
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fiq_.status = 0x80; // 'set always'.
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@ -455,6 +584,9 @@ private:
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uint16_t output;
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};
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Counter counters_[4];
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HalfDuplexSerial serial_;
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Keyboard keyboard_;
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};
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/// Primarily models the MEMC.
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