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70 lines
2.0 KiB
C++
70 lines
2.0 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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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_cycles(int number_of_cycles)
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{
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cycles_until_event_ -= number_of_cycles;
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while(cycles_until_event_ <= 0)
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{
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process_next_event();
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}
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}
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unsigned int TimedEventLoop::get_cycles_until_next_event()
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{
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return (unsigned int)std::max(cycles_until_event_, 0);
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}
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void TimedEventLoop::reset_timer()
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{
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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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{
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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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{
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// Calculate [interval]*[input clock rate] + [subcycles until this event].
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int64_t denominator = (int64_t)interval.clock_rate * (int64_t)subcycles_until_event_.clock_rate;
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int64_t numerator =
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(int64_t)subcycles_until_event_.clock_rate * (int64_t)input_clock_rate_ * (int64_t)interval.length +
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(int64_t)interval.clock_rate * (int64_t)subcycles_until_event_.length;
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// Simplify now, to prepare for stuffing into possibly 32-bit quantities
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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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// 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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cycles_until_event_ = (int)(numerator / denominator);
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subcycles_until_event_.length = (unsigned int)(numerator % denominator);
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subcycles_until_event_.clock_rate = (unsigned int)denominator;
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}
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Time TimedEventLoop::get_time_into_next_event()
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{
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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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