math.h File Reference

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Macros
#define	fr_add(_out, _a, _b)   !__builtin_add_overflow(_a, _b, _out)
	Adds two integers. More...
#define	fr_multiply(_out, _a, _b)   !__builtin_mul_overflow(_a, _b, _out)
	Multiplies two integers together. More...
#define	fr_sub(_out, _a, _b)   !__builtin_sub_overflow(_a, _b, _out)
	Subtracts two integers. More...
#define	ROUND_UP(_num, _mul)   (((((_num) + ((_mul) - 1))) / (_mul)) * (_mul))
	Round up - Works in all cases, but is slower. More...
#define	ROUND_UP_DIV(_x, _y)   (1 + (((_x) - 1) / (_y)))
	Get the ceiling value of integer division. More...
#define	ROUND_UP_POW2(_num, _mul)   (((_num) + ((_mul) - 1)) & ~((_mul) - 1))
	Round up - Only works if _mul is a power of 2 but avoids division. More...

Functions
static uint8_t	fr_high_bit_pos (uint64_t num)
	Find the highest order high bit in an unsigned 64 bit integer. More...
static uint8_t	fr_log10 (uint64_t num)
	Efficient calculation of log10 of a unsigned 64bit integer. More...
static uint8_t	fr_low_bit_pos (uint64_t num)
	Find the lowest order high bit in an unsigned 64 bit integer. More...

Macro Definition Documentation

fr_add

#define fr_add	(		_out,
			_a,
			_b
	)		!__builtin_add_overflow(_a, _b, _out)

Adds two integers.

Parameters

[in]	_out	Where to store the result.
[in]	_a	first argument to add.
[in]	_b	second argument to add.

Returns

• false on overflow.
• true if there was no overflow.

Definition at line 129 of file math.h.

fr_multiply

#define fr_multiply	(		_out,
			_a,
			_b
	)		!__builtin_mul_overflow(_a, _b, _out)

Multiplies two integers together.

Parameters

[in]	_out	Where to store the result.
[in]	_a	first argument to multiply.
[in]	_b	second argument to multiply.

Returns

• false on overflow.
• true if there was no overflow.

Definition at line 118 of file math.h.

fr_sub

#define fr_sub	(		_out,
			_a,
			_b
	)		!__builtin_sub_overflow(_a, _b, _out)

Subtracts two integers.

Parameters

[in]	_out	Where to store the result.
[in]	_a	first argument to subtract.
[in]	_b	second argument to subtract.

Returns

• false on overflow.
• true if there was no overflow.

Definition at line 140 of file math.h.

ROUND_UP

#define ROUND_UP	(		_num,
			_mul
	)		(((((_num) + ((_mul) - 1))) / (_mul)) * (_mul))

Round up - Works in all cases, but is slower.

Definition at line 148 of file math.h.

ROUND_UP_DIV

#define ROUND_UP_DIV	(		_x,
			_y
	)		(1 + (((_x) - 1) / (_y)))

Get the ceiling value of integer division.

Definition at line 153 of file math.h.

ROUND_UP_POW2

#define ROUND_UP_POW2	(		_num,
			_mul
	)		(((_num) + ((_mul) - 1)) & ~((_mul) - 1))

Round up - Only works if _mul is a power of 2 but avoids division.

Definition at line 144 of file math.h.

Function Documentation

fr_high_bit_pos()

static uint8_t fr_high_bit_pos ( uint64_t  num )

inlinestatic

Find the highest order high bit in an unsigned 64 bit integer.

Returns

0-64 indicating the position of the highest bit, with 0 indicating no high bits, 1 indicating the 1st bit and 64 indicating the last bit.

Definition at line 36 of file math.h.

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fr_log10()

static uint8_t fr_log10 ( uint64_t  num )

inlinestatic

Efficient calculation of log10 of a unsigned 64bit integer.

Parameters

[in]

num

to calculate log10 of.

Returns

log10 of the integer

Definition at line 78 of file math.h.

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fr_low_bit_pos()

static uint8_t fr_low_bit_pos ( uint64_t  num )

inlinestatic

Find the lowest order high bit in an unsigned 64 bit integer.

Returns

0-64 indicating the position of the lowest bit, with 0 indicating no high bits, 1 indicating the 1st bit and 64 indicating the last bit.

Definition at line 55 of file math.h.

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