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175 lines
6.6 KiB
C++
175 lines
6.6 KiB
C++
//
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// MFP68901.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 06/10/2019.
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// Copyright © 2019 Thomas Harte. All rights reserved.
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//
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#include "MFP68901.hpp"
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#define LOG_PREFIX "[MFP] "
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#include "../../Outputs/Log.hpp"
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using namespace Motorola::MFP68901;
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uint8_t MFP68901::read(int address) {
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address &= 0x1f;
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switch(address) {
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case 0x00: LOG("Read: general purpose IO"); break;
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case 0x01: LOG("Read: active edge"); break;
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case 0x02: LOG("Read: data direction"); break;
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case 0x03: LOG("Read: interrupt enable A"); break;
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case 0x04: LOG("Read: interrupt enable B"); break;
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case 0x05: LOG("Read: interrupt pending A"); break;
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case 0x06: LOG("Read: interrupt pending B"); break;
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case 0x07: LOG("Read: interrupt in-service A"); break;
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case 0x08: LOG("Read: interrupt in-service B"); break;
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case 0x09: LOG("Read: interrupt mask A"); break;
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case 0x0a: LOG("Read: interrupt mask B"); break;
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case 0x0b: LOG("Read: vector"); break;
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case 0x0c: LOG("Read: timer A control"); break;
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case 0x0d: LOG("Read: timer B control"); break;
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case 0x0e: LOG("Read: timers C/D control"); break;
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case 0x0f: case 0x10: case 0x11: case 0x12:
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return get_timer_data(address - 0xf);
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case 0x13: LOG("Read: sync character generator"); break;
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case 0x14: LOG("Read: USART control"); break;
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case 0x15: LOG("Read: receiver status"); break;
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case 0x16: LOG("Read: transmitter status"); break;
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case 0x17: LOG("Read: USART data"); break;
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}
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return 0x00;
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}
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void MFP68901::write(int address, uint8_t value) {
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address &= 0x1f;
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switch(address) {
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case 0x00: LOG("Write: general purpose IO"); break;
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case 0x01: LOG("Write: active edge"); break;
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case 0x02: LOG("Write: data direction"); break;
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case 0x03: LOG("Write: interrupt enable A"); break;
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case 0x04: LOG("Write: interrupt enable B"); break;
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case 0x05: LOG("Write: interrupt pending A"); break;
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case 0x06: LOG("Write: interrupt pending B"); break;
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case 0x07: LOG("Write: interrupt in-service A"); break;
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case 0x08: LOG("Write: interrupt in-service B"); break;
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case 0x09: LOG("Write: interrupt mask A"); break;
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case 0x0a: LOG("Write: interrupt mask B"); break;
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case 0x0b: LOG("Write: vector"); break;
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case 0x0c:
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case 0x0d: {
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const auto timer = address - 0xc;
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const bool reset = value & 0x10;
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switch(value & 0xf) {
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case 0x0: set_timer_mode(timer, TimerMode::Stopped, 0, reset); break;
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case 0x1: set_timer_mode(timer, TimerMode::Delay, 4, reset); break;
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case 0x2: set_timer_mode(timer, TimerMode::Delay, 10, reset); break;
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case 0x3: set_timer_mode(timer, TimerMode::Delay, 16, reset); break;
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case 0x4: set_timer_mode(timer, TimerMode::Delay, 50, reset); break;
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case 0x5: set_timer_mode(timer, TimerMode::Delay, 64, reset); break;
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case 0x6: set_timer_mode(timer, TimerMode::Delay, 100, reset); break;
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case 0x7: set_timer_mode(timer, TimerMode::Delay, 200, reset); break;
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case 0x8: set_timer_mode(timer, TimerMode::EventCount, 0, reset); break;
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case 0x9: set_timer_mode(timer, TimerMode::PulseWidth, 4, reset); break;
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case 0xa: set_timer_mode(timer, TimerMode::PulseWidth, 10, reset); break;
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case 0xb: set_timer_mode(timer, TimerMode::PulseWidth, 16, reset); break;
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case 0xc: set_timer_mode(timer, TimerMode::PulseWidth, 50, reset); break;
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case 0xd: set_timer_mode(timer, TimerMode::PulseWidth, 64, reset); break;
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case 0xe: set_timer_mode(timer, TimerMode::PulseWidth, 100, reset); break;
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case 0xf: set_timer_mode(timer, TimerMode::PulseWidth, 200, reset); break;
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}
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} break;
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case 0x0e:
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switch(value & 7) {
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case 0: set_timer_mode(3, TimerMode::Stopped, 0, false); break;
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case 1: set_timer_mode(3, TimerMode::Delay, 4, false); break;
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case 2: set_timer_mode(3, TimerMode::Delay, 10, false); break;
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case 3: set_timer_mode(3, TimerMode::Delay, 16, false); break;
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case 4: set_timer_mode(3, TimerMode::Delay, 50, false); break;
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case 5: set_timer_mode(3, TimerMode::Delay, 64, false); break;
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case 6: set_timer_mode(3, TimerMode::Delay, 100, false); break;
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case 7: set_timer_mode(3, TimerMode::Delay, 200, false); break;
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}
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switch((value >> 4) & 7) {
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case 0: set_timer_mode(2, TimerMode::Stopped, 0, false); break;
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case 1: set_timer_mode(2, TimerMode::Delay, 4, false); break;
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case 2: set_timer_mode(2, TimerMode::Delay, 10, false); break;
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case 3: set_timer_mode(2, TimerMode::Delay, 16, false); break;
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case 4: set_timer_mode(2, TimerMode::Delay, 50, false); break;
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case 5: set_timer_mode(2, TimerMode::Delay, 64, false); break;
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case 6: set_timer_mode(2, TimerMode::Delay, 100, false); break;
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case 7: set_timer_mode(2, TimerMode::Delay, 200, false); break;
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}
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break;
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case 0x0f: case 0x10: case 0x11: case 0x12:
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set_timer_data(address - 0xf, value);
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break;
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case 0x13: LOG("Write: sync character generator"); break;
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case 0x14: LOG("Write: USART control"); break;
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case 0x15: LOG("Write: receiver status"); break;
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case 0x16: LOG("Write: transmitter status"); break;
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case 0x17: LOG("Write: USART data"); break;
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}
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}
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void MFP68901::run_for(HalfCycles time) {
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cycles_left_ += time;
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// TODO: this is the stupidest possible implementation. Improve.
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int cycles = cycles_left_.flush<Cycles>().as_int();
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while(cycles--) {
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for(int c = 0; c < 4; ++c) {
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if(timers_[c].mode >= TimerMode::Delay) {
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--timers_[c].divisor;
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if(!timers_[c].divisor) {
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timers_[c].divisor = timers_[c].prescale;
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decrement_timer(c);
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}
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}
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}
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}
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}
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HalfCycles MFP68901::get_next_sequence_point() {
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return HalfCycles(-1);
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}
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// MARK: - Timers
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void MFP68901::set_timer_mode(int timer, TimerMode mode, int prescale, bool reset_timer) {
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timers_[timer].mode = mode;
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timers_[timer].prescale = prescale;
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if(reset_timer) {
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timers_[timer].divisor = prescale;
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timers_[timer].value = timers_[timer].reload_value;
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}
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}
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void MFP68901::set_timer_data(int timer, uint8_t value) {
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if(timers_[timer].mode == TimerMode::Stopped) {
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timers_[timer].value = value;
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}
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timers_[timer].reload_value = value;
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}
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uint8_t MFP68901::get_timer_data(int timer) {
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return timers_[timer].value;
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}
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void MFP68901::set_timer_event_input(int channel, bool value) {
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if(timers_[channel].event_input == value) return;
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timers_[channel].event_input = value;
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if(timers_[channel].mode == TimerMode::EventCount && !value) { /* TODO: which edge is counted? "as defined by the associated Interrupt Channel’s edge bit"? */
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decrement_timer(channel);
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}
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}
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void MFP68901::decrement_timer(int timer) {
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--timers_[timer].value;
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if(!timers_[timer].value) {
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// TODO: interrupt. Reload, possibly.
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}
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}
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