frac.h File Reference

Detailed Description

Author

Joakim Nohlgård joaki.nosp@m.m.no.nosp@m.hlgar.nosp@m.d@ei.nosp@m.stec..nosp@m.se

Definition in file frac.h.

#include <stdint.h>

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Data Structures
struct	frac_t
	frac descriptor for fraction consisting of two 32 bit integers More...
uint32_t	gcd32 (uint32_t u, uint32_t v)
	Compute greatest common divisor of u and v. More...
void	frac_init (frac_t *frac, uint32_t num, uint32_t den)
	Initialize frac_t struct. More...
static uint32_t	frac_scale (const frac_t *frac, uint32_t x)
	Scale a 32 bit integer by a 32/32 rational number. More...

Function Documentation

frac_init()

void frac_init	(	frac_t *	frac,
		uint32_t	num,
		uint32_t	den
	)

Initialize frac_t struct.

This function computes the mathematical parameters used by the frac algorithm.

Note

If num > den, the result from frac_scale modulo 2**32.

Precondition

den must not be 0

Parameters

[out]	frac	pointer to frac descriptor to initialize
[in]	num	numerator
[in]	den	denominator

frac_scale()

static uint32_t frac_scale ( const frac_t *  frac, uint32_t  x  )

inlinestatic

Scale a 32 bit integer by a 32/32 rational number.

Parameters

[in]	frac	scaling fraction
[in]	x	unscaled integer

Returns

(x * frac) % 2**32, avoiding truncation

Definition at line 91 of file frac.h.

gcd32()

uint32_t gcd32	(	uint32_t	u,
		uint32_t	v
	)

Compute greatest common divisor of u and v.

Parameters

[in]	u	first operand
[in]	v	second operand

Returns

Greatest common divisor of u and v