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6c468a134b
Create a clock class which can be queried for current timestamp in nanoseconds. Also implements a simple HPET class as one possible clock source. Tags: time
45 lines
1.2 KiB
C++
45 lines
1.2 KiB
C++
#pragma once
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/// \file clock.h
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/// The kernel time keeping interface
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#include <stdint.h>
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class clock
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{
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public:
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/// A source is a function that returns the current
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/// value of some clock source.
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using source = uint64_t (*)(void*);
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/// Constructor.
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/// \arg rate Number of source ticks per ns
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/// \arg source Function for the clock source
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/// \arg data Data to pass to the source function
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clock(uint64_t rate, source source_func, void *data);
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/// Get the current value of the clock.
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/// \returns Current value of the source, in ns
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/// TODO: optimize divison by finding a multiply and
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/// shift value instead
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inline uint64_t value() const { return m_source(m_data) / m_rate; }
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/// Update the internal state via the source
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/// \returns Current value of the clock
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inline void update() { m_current = value(); return m_current; }
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/// Wait in a tight loop
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/// \arg interval Time to wait, in ns
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void spinwait(uint64_t ns) const;
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/// Get the master clock
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static clock & get() { return *s_instance; }
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private:
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uint64_t m_current; ///< current ns count
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uint64_t m_rate; ///< source ticks per ns
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void *m_data;
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source m_source;
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static clock *s_instance;
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};
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