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106 lines
3.5 KiB
C++
106 lines
3.5 KiB
C++
//
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// TimedEventLoop.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 29/07/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "TimedEventLoop.hpp"
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#include "../NumberTheory/Factors.hpp"
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#include <algorithm>
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#include <cassert>
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using namespace Storage;
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TimedEventLoop::TimedEventLoop(unsigned int input_clock_rate) :
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input_clock_rate_(input_clock_rate) {}
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void TimedEventLoop::run_for(const Cycles cycles) {
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int remaining_cycles = cycles.as_int();
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#ifndef NDEBUG
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int cycles_advanced = 0;
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#endif
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while(cycles_until_event_ <= remaining_cycles) {
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#ifndef NDEBUG
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cycles_advanced += cycles_until_event_;
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#endif
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advance(cycles_until_event_);
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remaining_cycles -= cycles_until_event_;
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cycles_until_event_ = 0;
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process_next_event();
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}
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if(remaining_cycles) {
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cycles_until_event_ -= remaining_cycles;
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#ifndef NDEBUG
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cycles_advanced += remaining_cycles;
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#endif
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advance(remaining_cycles);
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}
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assert(cycles_advanced == cycles.as_int());
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assert(cycles_until_event_ > 0);
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}
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unsigned int TimedEventLoop::get_cycles_until_next_event() {
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return static_cast<unsigned int>(std::max(cycles_until_event_, 0));
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}
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unsigned int TimedEventLoop::get_input_clock_rate() {
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return input_clock_rate_;
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}
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void TimedEventLoop::reset_timer() {
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subcycles_until_event_.set_zero();
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cycles_until_event_ = 0;
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}
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void TimedEventLoop::jump_to_next_event() {
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reset_timer();
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process_next_event();
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}
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void TimedEventLoop::set_next_event_time_interval(Time interval) {
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// Calculate [interval]*[input clock rate] + [subcycles until this event].
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int64_t denominator = static_cast<int64_t>(interval.clock_rate) * static_cast<int64_t>(subcycles_until_event_.clock_rate);
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int64_t numerator =
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static_cast<int64_t>(subcycles_until_event_.clock_rate) * static_cast<int64_t>(input_clock_rate_) * static_cast<int64_t>(interval.length) +
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static_cast<int64_t>(interval.clock_rate) * static_cast<int64_t>(subcycles_until_event_.length);
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// Simplify if necessary: try just simplifying the interval and recalculating; if that doesn't
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// work then try simplifying the whole thing.
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if(numerator < 0 || denominator < 0 || denominator > std::numeric_limits<unsigned int>::max()) {
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interval.simplify();
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denominator = static_cast<int64_t>(interval.clock_rate) * static_cast<int64_t>(subcycles_until_event_.clock_rate);
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numerator =
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static_cast<int64_t>(subcycles_until_event_.clock_rate) * static_cast<int64_t>(input_clock_rate_) * static_cast<int64_t>(interval.length) +
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static_cast<int64_t>(interval.clock_rate) * static_cast<int64_t>(subcycles_until_event_.length);
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}
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if(numerator < 0 || denominator < 0 || denominator > std::numeric_limits<unsigned int>::max()) {
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int64_t common_divisor = NumberTheory::greatest_common_divisor(numerator % denominator, denominator);
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denominator /= common_divisor;
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numerator /= common_divisor;
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}
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// TODO: if that doesn't work then reduce precision.
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// So this event will fire in the integral number of cycles from now, putting us at the remainder
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// number of subcycles
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assert(cycles_until_event_ == 0);
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cycles_until_event_ += static_cast<int>(numerator / denominator);
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assert(cycles_until_event_ >= 0);
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subcycles_until_event_.length = static_cast<unsigned int>(numerator % denominator);
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subcycles_until_event_.clock_rate = static_cast<unsigned int>(denominator);
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subcycles_until_event_.simplify();
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}
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Time TimedEventLoop::get_time_into_next_event() {
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// TODO: calculate, presumably as [length of interval] - ([cycles left] + [subcycles left])
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Time zero;
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return zero;
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}
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