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CLK/Storage/Storage.hpp
2019-06-05 14:43:34 -04:00

295 lines
9.5 KiB
C++

//
// Storage.hpp
// Clock Signal
//
// Created by Thomas Harte on 10/07/2016.
// Copyright 2016 Thomas Harte. All rights reserved.
//
#ifndef Storage_hpp
#define Storage_hpp
#include "../NumberTheory/Factors.hpp"
#include <cmath>
#include <cstdint>
#include <limits>
namespace Storage {
/*!
Contains either an absolute time or a time interval, described as a quotient, in terms of a
clock rate to which the time is relative and its length in cycles based on that clock rate.
*/
struct Time {
unsigned int length, clock_rate;
Time() : length(0), clock_rate(1) {}
Time(unsigned int unsigned_int_value) : length(unsigned_int_value), clock_rate(1) {}
Time(int int_value) : Time(static_cast<unsigned int>(int_value)) {}
Time(unsigned int length, unsigned int clock_rate) : length(length), clock_rate(clock_rate) {}
Time(int length, int clock_rate) : Time(static_cast<unsigned int>(length), static_cast<unsigned int>(clock_rate)) {}
Time(uint64_t length, uint64_t clock_rate) {
install_result(length, clock_rate);
}
Time(float value) {
install_float(value);
}
/*!
Reduces this @c Time to its simplest form; eliminates all common factors from @c length
and @c clock_rate.
*/
void simplify() {
unsigned int common_divisor = NumberTheory::greatest_common_divisor(length, clock_rate);
length /= common_divisor;
clock_rate /= common_divisor;
}
/*!
@returns the floating point conversion of this @c Time. This will often be less precise.
*/
template <typename T> T get() const {
return static_cast<T>(length) / static_cast<T>(clock_rate);
}
inline bool operator < (const Time &other) const {
return (uint64_t)other.clock_rate * (uint64_t)length < (uint64_t)clock_rate * (uint64_t)other.length;
}
inline bool operator <= (const Time &other) const {
return (uint64_t)other.clock_rate * (uint64_t)length <= (uint64_t)clock_rate * (uint64_t)other.length;
}
inline bool operator > (const Time &other) const {
return (uint64_t)other.clock_rate * (uint64_t)length > (uint64_t)clock_rate * (uint64_t)other.length;
}
inline bool operator >= (const Time &other) const {
return (uint64_t)other.clock_rate * (uint64_t)length >= (uint64_t)clock_rate * (uint64_t)other.length;
}
inline bool operator == (const Time &other) const {
return (uint64_t)other.clock_rate * (uint64_t)length == (uint64_t)clock_rate * (uint64_t)other.length;
}
inline Time operator + (const Time &other) const {
if(!other.length) return *this;
uint64_t result_length;
uint64_t result_clock_rate;
if(clock_rate == other.clock_rate) {
result_length = (uint64_t)length + (uint64_t)other.length;
result_clock_rate = clock_rate;
} else {
result_length = (uint64_t)length * (uint64_t)other.clock_rate + (uint64_t)other.length * (uint64_t)clock_rate;
result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.clock_rate;
}
return Time(result_length, result_clock_rate);
}
inline Time &operator += (const Time &other) {
if(!other.length) return *this;
if(!length) {
*this = other;
return *this;
}
uint64_t result_length;
uint64_t result_clock_rate;
if(clock_rate == other.clock_rate) {
result_length = (uint64_t)length + (uint64_t)other.length;
result_clock_rate = (uint64_t)clock_rate;
} else {
result_length = (uint64_t)length * (uint64_t)other.clock_rate + (uint64_t)other.length * (uint64_t)clock_rate;
result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.clock_rate;
}
install_result(result_length, result_clock_rate);
return *this;
}
inline Time operator - (const Time &other) const {
if(!other.length) return *this;
uint64_t result_length;
uint64_t result_clock_rate;
if(clock_rate == other.clock_rate) {
result_length = (uint64_t)length - (uint64_t)other.length;
result_clock_rate = clock_rate;
} else {
result_length = (uint64_t)length * (uint64_t)other.clock_rate - (uint64_t)other.length * (uint64_t)clock_rate;
result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.clock_rate;
}
return Time(result_length, result_clock_rate);
}
inline Time operator -= (const Time &other) {
if(!other.length) return *this;
uint64_t result_length;
uint64_t result_clock_rate;
if(clock_rate == other.clock_rate) {
result_length = (uint64_t)length - (uint64_t)other.length;
result_clock_rate = (uint64_t)clock_rate;
} else {
result_length = (uint64_t)length * (uint64_t)other.clock_rate - (uint64_t)other.length * (uint64_t)clock_rate;
result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.clock_rate;
}
install_result(result_length, result_clock_rate);
return *this;
}
inline Time operator * (const Time &other) const {
uint64_t result_length = (uint64_t)length * (uint64_t)other.length;
uint64_t result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.clock_rate;
return Time(result_length, result_clock_rate);
}
inline Time &operator *= (const Time &other) {
uint64_t result_length = (uint64_t)length * (uint64_t)other.length;
uint64_t result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.clock_rate;
install_result(result_length, result_clock_rate);
return *this;
}
inline Time operator * (unsigned int multiplier) const {
uint64_t result_length = (uint64_t)length * (uint64_t)multiplier;
uint64_t result_clock_rate = (uint64_t)clock_rate;
return Time(result_length, result_clock_rate);
}
inline Time &operator *= (unsigned int multiplier) {
uint64_t result_length = (uint64_t)length * (uint64_t)multiplier;
uint64_t result_clock_rate = (uint64_t)clock_rate;
install_result(result_length, result_clock_rate);
return *this;
}
inline Time operator / (const Time &other) const {
uint64_t result_length = (uint64_t)length * (uint64_t)other.clock_rate;
uint64_t result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.length;
return Time(result_length, result_clock_rate);
}
inline Time &operator /= (const Time &other) {
uint64_t result_length = (uint64_t)length * (uint64_t)other.clock_rate;
uint64_t result_clock_rate = (uint64_t)clock_rate * (uint64_t)other.length;
install_result(result_length, result_clock_rate);
return *this;
}
inline Time operator / (unsigned int divisor) const {
uint64_t result_length = (uint64_t)length;
uint64_t result_clock_rate = (uint64_t)clock_rate * (uint64_t)divisor;
return Time(result_length, result_clock_rate);
}
inline Time &operator /= (unsigned int divisor) {
uint64_t result_length = (uint64_t)length;
uint64_t result_clock_rate = (uint64_t)clock_rate * (uint64_t)divisor;
install_result(result_length, result_clock_rate);
return *this;
}
inline void set_zero() {
length = 0;
clock_rate = 1;
}
inline void set_one() {
length = 1;
clock_rate = 1;
}
static Time max() {
return Time(std::numeric_limits<unsigned int>::max());
}
private:
inline void install_result(uint64_t long_length, uint64_t long_clock_rate) {
if(long_length <= std::numeric_limits<unsigned int>::max() && long_clock_rate <= std::numeric_limits<unsigned int>::max()) {
length = static_cast<unsigned int>(long_length);
clock_rate = static_cast<unsigned int>(long_clock_rate);
return;
}
// TODO: switch to appropriate values if the result is too large or small to fit, even with trimmed accuracy.
if(!long_length) {
length = 0;
clock_rate = 1;
return;
}
while(!(long_length&0xf) && !(long_clock_rate&0xf)) {
long_length >>= 4;
long_clock_rate >>= 4;
}
while(!(long_length&1) && !(long_clock_rate&1)) {
long_length >>= 1;
long_clock_rate >>= 1;
}
if(long_length > std::numeric_limits<unsigned int>::max() || long_clock_rate > std::numeric_limits<unsigned int>::max()) {
uint64_t common_divisor = NumberTheory::greatest_common_divisor(long_length, long_clock_rate);
long_length /= common_divisor;
long_clock_rate /= common_divisor;
// Okay, in desperation accept a loss of accuracy.
while(
(long_length > std::numeric_limits<unsigned int>::max() || long_clock_rate > std::numeric_limits<unsigned int>::max()) &&
(long_clock_rate > 1)) {
long_length >>= 1;
long_clock_rate >>= 1;
}
}
if(long_length <= std::numeric_limits<unsigned int>::max() && long_clock_rate <= std::numeric_limits<unsigned int>::max()) {
length = static_cast<unsigned int>(long_length);
clock_rate = static_cast<unsigned int>(long_clock_rate);
} else {
length = std::numeric_limits<unsigned int>::max();
clock_rate = 1u;
}
}
inline void install_float(float value) {
// Grab the float's native mantissa and exponent.
int exponent;
const float mantissa = frexpf(value, &exponent);
// Turn the mantissa into an int, and adjust the exponent
// appropriately.
const uint64_t loaded_mantissa = uint64_t(ldexpf(mantissa, 24));
const auto relative_exponent = exponent - 24;
// If the mantissa is negative and its absolute value fits within a 64-bit integer,
// just load up.
if(relative_exponent <= 0 && relative_exponent > -64) {
install_result(loaded_mantissa, uint64_t(1 << -relative_exponent));
return;
}
// If the exponent is positive but doesn't cause loaded_mantissa to overflow,
// install with the natural encoding.
if(relative_exponent > 0 && relative_exponent < (64 - 24)) {
install_result(loaded_mantissa << relative_exponent, 1);
return;
}
// Otherwise, if this number is too large to store, store the maximum value.
if(relative_exponent > 0) {
install_result(std::numeric_limits<uint64_t>::max(), 1);
return;
}
// If the number is too small to store accurately, store 0.
if(relative_exponent < 0) {
install_result(0, 1);
return;
}
}
};
}
#endif /* Storage_h */