High Precision Q64.64

Functions and class for high precision Q64.64 fixed point arithmetic. More...

Collaboration diagram for High Precision Q64.64:

Classes
class	ns3::int64x64_t
	High precision numerical type, implementing Q64.64 fixed precision. More...

Functions
int64x64_t	ns3::Abs (const int64x64_t &value)
	Absolute value. More...
int64x64_t	ns3::Max (const int64x64_t &a, const int64x64_t &b)
	Maximum. More...
int64x64_t	ns3::Min (const int64x64_t &a, const int64x64_t &b)
	Minimum. More...
int64x64_t	ns3::operator! (const int64x64_t &lhs)
	Logical not operator. More...
bool	ns3::operator!= (const int64x64_t &lhs, const int64x64_t &rhs)
	Inequality operator. More...
int64x64_t	ns3::operator* (const int64x64_t &lhs, const int64x64_t &rhs)
	Multiplication operator. More...
int64x64_t &	ns3::operator*= (int64x64_t &lhs, const int64x64_t &rhs)
	Compound multiplication operator. More...
int64x64_t	ns3::operator+ (const int64x64_t &lhs, const int64x64_t &rhs)
	Addition operator. More...
int64x64_t	ns3::operator+ (const int64x64_t &lhs)
	Unary plus operator. More...
int64x64_t &	ns3::operator+= (int64x64_t &lhs, const int64x64_t &rhs)
	Compound addition operator. More...
int64x64_t	ns3::operator- (const int64x64_t &lhs, const int64x64_t &rhs)
	Subtraction operator. More...
int64x64_t	ns3::operator- (const int64x64_t &lhs)
	Unary negation operator (change sign operator). More...
int64x64_t &	ns3::operator-= (int64x64_t &lhs, const int64x64_t &rhs)
	Compound subtraction operator. More...
int64x64_t	ns3::operator/ (const int64x64_t &lhs, const int64x64_t &rhs)
	Division operator. More...
int64x64_t &	ns3::operator/= (int64x64_t &lhs, const int64x64_t &rhs)
	Compound division operator. More...
bool	ns3::operator< (const int64x64_t &lhs, const int64x64_t &rhs)
	Less than operator. More...
std::ostream &	ns3::operator<< (std::ostream &os, const int64x64_t &value)
	Output streamer for int64x64_t. More...
bool	ns3::operator<= (const int64x64_t &lhs, const int64x64_t &rhs)
	Less or equal operator. More...
bool	ns3::operator== (const int64x64_t &lhs, const int64x64_t &rhs)
	Equality operator. More...
bool	ns3::operator> (const int64x64_t &lhs, const int64x64_t &rhs)
	Greater operator. More...
bool	ns3::operator>= (const int64x64_t &lhs, const int64x64_t &rhs)
	Greater or equal operator. More...
std::istream &	ns3::operator>> (std::istream &is, int64x64_t &value)
	Input streamer for int64x64_t. More...
static bool	ns3::output_sign (const int128_t sa, const int128_t sb, uint128_t &ua, uint128_t &ub)
	Compute the sign of the result of multiplying or dividing Q64.64 fixed precision operands. More...
static bool	ns3::output_sign (const cairo_int128_t sa, const cairo_int128_t sb, cairo_uint128_t &ua, cairo_uint128_t &ub)
	Compute the sign of the result of multiplying or dividing Q64.64 fixed precision operands. More...
static uint64_t	ns3::ReadHiDigits (std::string str)
	Read the integer portion of a number from a string containing just the integral digits (no decimal point or fractional part). More...
static uint64_t	ns3::ReadLoDigits (std::string str)
	Read the fractional part of a number from a string containing just the decimal digits of the fractional part (no integral part or decimal point). More...

Detailed Description

Functions and class for high precision Q64.64 fixed point arithmetic.

A Q64.64 fixed precision number consists of:

Bits	Function
1	Sign bit
63	Integer portion
64	Fractional portion

The high word consists of the sign bit and integer value; the low word is the fractional part, unscaled.

All standard arithmetic operations are supported:

Category	Operators
Computation	+, +=, -, -=, *, *=, /, /=
Comparison	==, !=, <, <=, >, >=
Unary	+, -, !

Function Documentation

int64x64_t ns3::Abs ( const int64x64_t &  value )

inline

Absolute value.

Parameters

value

The value to operate on.

Returns

The absolute value of value.

Definition at line 178 of file int64x64.h.

Referenced by ns3::int64x64::test::Int64x64InputOutputTestCase::Check(), ns3::int64x64::test::Int64x64ArithmeticTestCase::Check(), ns3::int64x64::test::Int64x64DoubleTestCase::Check(), ns3::int64x64::test::Int64x64InvertTestCase::CheckCase(), ns3::RttMeanDeviation::FloatingPointUpdate(), and ns3::DelayJitterEstimation::RecordRx().

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int64x64_t ns3::Max ( const int64x64_t &  a, const int64x64_t &  b  )

inline

Maximum.

Parameters

[in]	a	The first value.
[in]	b	The second value.

Returns

The larger of the arguments.

Definition at line 203 of file int64x64.h.

Referenced by ns3::int64x64::test::Int64x64HiLoTestCase::Check(), ns3::int64x64::test::Int64x64InputTestCase::Check(), ns3::TcpSocketBase::DoPeerClose(), ns3::AarfWifiManager::DoReportDataFailed(), ns3::AarfcdWifiManager::DoReportDataFailed(), ns3::TcpSocketBase::EstimateRtt(), ns3::WifiPhyStateHelper::GetDelayUntilIdle(), ns3::WifiPhyStateHelper::LogPreviousIdleAndCcaBusyStates(), ns3::DcfManager::MostRecent(), ns3::TcpSocketBase::NewAck(), ns3::TcpSocketBase::SendEmptyPacket(), ns3::WifiPhyStateHelper::SwitchToChannelSwitching(), ns3::WifiPhyStateHelper::SwitchToRx(), ns3::WifiPhyStateHelper::SwitchToSleep(), and ns3::WifiPhyStateHelper::SwitchToTx().

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int64x64_t ns3::Min ( const int64x64_t &  a, const int64x64_t &  b  )

inline

Minimum.

Parameters

[in]	a	The first value.
[in]	b	The second value.

Returns

The smaller of the arguments.

Definition at line 191 of file int64x64.h.

Referenced by ns3::RemoteChannelBundle::AddChannel(), ns3::NullMessageSimulatorImpl::CalculateGuaranteeTime(), ns3::int64x64::test::Int64x64HiLoTestCase::Check(), ns3::int64x64::test::Int64x64InputTestCase::Check(), ns3::AarfWifiManager::DoGetDataTxVector(), ns3::ConstantRateWifiManager::DoGetDataTxVector(), ns3::CaraWifiManager::DoGetDataTxVector(), ns3::AmrrWifiManager::DoGetDataTxVector(), ns3::OnoeWifiManager::DoGetDataTxVector(), ns3::ArfWifiManager::DoGetDataTxVector(), ns3::IdealWifiManager::DoGetDataTxVector(), ns3::RraaWifiManager::DoGetDataTxVector(), ns3::AarfcdWifiManager::DoGetDataTxVector(), ns3::ParfWifiManager::DoGetDataTxVector(), ns3::AparfWifiManager::DoGetDataTxVector(), ns3::MinstrelWifiManager::DoGetDataTxVector(), ns3::AarfWifiManager::DoGetRtsTxVector(), ns3::ConstantRateWifiManager::DoGetRtsTxVector(), ns3::CaraWifiManager::DoGetRtsTxVector(), ns3::AmrrWifiManager::DoGetRtsTxVector(), ns3::OnoeWifiManager::DoGetRtsTxVector(), ns3::ArfWifiManager::DoGetRtsTxVector(), ns3::IdealWifiManager::DoGetRtsTxVector(), ns3::RraaWifiManager::DoGetRtsTxVector(), ns3::AarfcdWifiManager::DoGetRtsTxVector(), ns3::ParfWifiManager::DoGetRtsTxVector(), ns3::AparfWifiManager::DoGetRtsTxVector(), ns3::MinstrelWifiManager::DoGetRtsTxVector(), ns3::AarfWifiManager::DoReportDataFailed(), ns3::AarfcdWifiManager::DoReportDataFailed(), ns3::RemoteChannelBundleManager::GetSafeTime(), ns3::NullMessageSimulatorImpl::NullMessageEventHandler(), and ns3::TcpSocketBase::SendDataPacket().

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int64x64_t ns3::operator! ( const int64x64_t &  lhs )

inline

Logical not operator.

Definition at line 420 of file int64x64-128.h.

References ns3::int64x64_t::_v.

bool ns3::operator!= ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Inequality operator.

Definition at line 123 of file int64x64.h.

int64x64_t ns3::operator* ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Multiplication operator.

Definition at line 102 of file int64x64.h.

int64x64_t& ns3::operator*= ( int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Compound multiplication operator.

Definition at line 385 of file int64x64-128.h.

References ns3::int64x64_t::Mul().

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int64x64_t ns3::operator+ ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Addition operator.

Definition at line 80 of file int64x64.h.

int64x64_t ns3::operator+ ( const int64x64_t &  lhs )

inline

Unary plus operator.

Definition at line 404 of file int64x64-128.h.

int64x64_t& ns3::operator+= ( int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Compound addition operator.

Definition at line 367 of file int64x64-128.h.

References ns3::int64x64_t::_v.

int64x64_t ns3::operator- ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Subtraction operator.

Definition at line 91 of file int64x64.h.

int64x64_t ns3::operator- ( const int64x64_t &  lhs )

inline

Unary negation operator (change sign operator).

Definition at line 412 of file int64x64-128.h.

References ns3::int64x64_t::_v.

int64x64_t& ns3::operator-= ( int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Compound subtraction operator.

Definition at line 376 of file int64x64-128.h.

References ns3::int64x64_t::_v.

int64x64_t ns3::operator/ ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Division operator.

Definition at line 113 of file int64x64.h.

int64x64_t& ns3::operator/= ( int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Compound division operator.

Definition at line 394 of file int64x64-128.h.

References ns3::int64x64_t::Div().

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bool ns3::operator< ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Less than operator.

Definition at line 350 of file int64x64-128.h.

References ns3::int64x64_t::_v.

std::ostream & ns3::operator<<	(	std::ostream &	os,
		const int64x64_t &	value
	)

Output streamer for int64x64_t.

Internal:

This algorithm is exact to the precision requested, up to the full 64 decimal digits required to exactly represent a 64-bit fraction.

Proper rounding turns out to be surprisingly hard. In y.xxxx5|6, where the | marks follows the last output digit, rounding the 5|6 to 6| is straightforward. However, rounding y.xxx99|6 should result in y.xx100|. Notice the effect of rounding percolates to higher digits. We accumulate the output digits in a string, then carry out the rounding in the string directly.

Values are printed with the following format flags (independent of the the stream flags):

• showpos
• left

The stream width is ignored. If floatfield is set, precision decimal places are printed. If floatfield is not set, all digits of the fractional part are printed, up to the representation limit of 20 digits; trailing zeros are omitted.

Parameters

[in]	os	The output stream.
[in]	value	The numerical value to print.

Returns

The stream.

Definition at line 49 of file int64x64.cc.

References ns3::int64x64_t::GetHigh(), ns3::int64x64_t::GetLow(), HEXHILOW, NS_ASSERT_MSG, and NS_LOG_LOGIC.

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bool ns3::operator<= ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Less or equal operator.

Definition at line 131 of file int64x64.h.

bool ns3::operator== ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Equality operator.

Definition at line 342 of file int64x64-128.h.

References ns3::int64x64_t::_v.

bool ns3::operator> ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Greater operator.

Definition at line 358 of file int64x64-128.h.

References ns3::int64x64_t::_v.

bool ns3::operator>= ( const int64x64_t &  lhs, const int64x64_t &  rhs  )

inline

Greater or equal operator.

Definition at line 139 of file int64x64.h.

std::istream & ns3::operator>>	(	std::istream &	is,
		int64x64_t &	value
	)

Input streamer for int64x64_t.

Parameters

[in]	is	The input stream.
[out]	value	The numerical value to set.

Returns

The stream.

Definition at line 208 of file int64x64.cc.

References ns3::ReadHiDigits(), and ns3::ReadLoDigits().

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static bool ns3::output_sign ( const int128_t  sa, const int128_t  sb, uint128_t &  ua, uint128_t &  ub  )

inlinestatic

Compute the sign of the result of multiplying or dividing Q64.64 fixed precision operands.

Parameters

[in]	sa	The signed value of the first operand.
[in]	sb	The signed value of the second operand.
[out]	ua	The unsigned magnitude of the first operand.
[out]	ub	The unsigned magnitude of the second operand.

Returns

True if the result will be negative.

Definition at line 45 of file int64x64-128.cc.

Referenced by ns3::int64x64_t::Div(), and ns3::int64x64_t::Mul().

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static bool ns3::output_sign ( const cairo_int128_t  sa, const cairo_int128_t  sb, cairo_uint128_t &  ua, cairo_uint128_t &  ub  )

inlinestatic

Compute the sign of the result of multiplying or dividing Q64.64 fixed precision operands.

Parameters

[in]	sa	The signed value of the first operand.
[in]	sb	The signed value of the second operand.
[out]	ua	The unsigned magnitude of the first operand.
[out]	ub	The unsigned magnitude of the second operand.

Returns

True if the result will be negative.

Definition at line 53 of file int64x64-cairo.cc.

References _cairo_int128_negative, _cairo_int128_to_uint128, and _cairo_uint128_negate().

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static uint64_t ns3::ReadHiDigits ( std::string  str )

static

Read the integer portion of a number from a string containing just the integral digits (no decimal point or fractional part).

Parameters

[in]

str

The string representation of the integral part of a number, with no fractional part or decimal point.

Returns

The integer.

Definition at line 166 of file int64x64.cc.

Referenced by ns3::operator>>().

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static uint64_t ns3::ReadLoDigits ( std::string  str )

static

Read the fractional part of a number from a string containing just the decimal digits of the fractional part (no integral part or decimal point).

Parameters

[in]

str

The string representation of the fractional part of a number, without integral part or decimal point.

Returns

The decimal portion of the input number.

Definition at line 189 of file int64x64.cc.

References ns3::int64x64_t::GetLow(), and NS_ASSERT_MSG.

Referenced by ns3::operator>>().

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