math.h File Reference

API for a small collection of mathematical functions. More...

#include <stdbool.h>
#include <stdint.h>
#include "midi.h"

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Data Structures
struct	linear_range
	Configuration for a linear scaling function. More...

Macros
#define	FIXED_POINT   16
	Width of the fractional part of fixed point numbers. More...

Typedefs
typedef uint32_t	fixed_t
	Datatype for fixed point numbers. More...
typedef uint64_t	fixed_accu_t
	Datatype for accumulators in fixed point number arithmetic functions. More...

Functions
void	init_linear_from_midi (struct linear_range *config)
	Initializes a linear function to map from MIDI values to an arbitrary integer range. More...
void	init_linear_to_midi (struct linear_range *config)
	Initializes a linear function to map from an arbitrary integer range to MIDI values. More...
uint16_t	linear_from_midi (const struct linear_range *config, midi_value_t midi_value)
	Yields an integer in the configured range that corresponds to the given MIDI value. More...
midi_value_t	linear_to_midi (const struct linear_range *config, uint16_t input)
	Yields the MIDI value [0,127] from a given integer in the configured range. More...
static fixed_t	fixed_from_int (const uint16_t value)
	Converts an integer to a fixed point number. More...
static fixed_t	fixed_div (const fixed_t a, const fixed_t b)
	Performs a division of two fixed point numbers. More...
static fixed_t	fixed_mpy (const fixed_t a, const fixed_t b)
	Multiplies two fixed point numbers. More...
static uint16_t	fixed_to_int (fixed_t value)
	Converts fixed point number to an integer. More...

Detailed Description

API for a small collection of mathematical functions.

Macro Definition Documentation

FIXED_POINT

#define FIXED_POINT   16

Width of the fractional part of fixed point numbers.

Typedef Documentation

fixed_accu_t

typedef uint64_t fixed_accu_t

Datatype for accumulators in fixed point number arithmetic functions.

fixed_t

typedef uint32_t fixed_t

Datatype for fixed point numbers.

Function Documentation

fixed_div()

static fixed_t fixed_div ( const fixed_t  a, const fixed_t  b  )

inlinestatic

Performs a division of two fixed point numbers.

Note: You do not have to use this function when you want to divide a fixed point number by a "normal" integer, because the division done in this function cancels out the multiplication in fixed_from_int().

Parameters

a	the dividend
b	the divisor

Returns

the quotient as fixed point number

fixed_from_int()

static fixed_t fixed_from_int ( const uint16_t  value )

inlinestatic

Converts an integer to a fixed point number.

Parameters

value

the integer value to convert

Returns

the value as fixed point number

fixed_mpy()

static fixed_t fixed_mpy ( const fixed_t  a, const fixed_t  b  )

inlinestatic

Multiplies two fixed point numbers.

Note: You do not have to use this function when one of the two operands you want to multiply is a "normal" integer, because the division done in this function and the multiplication in fixed_from_int() cancel out.

Parameters

a	the first operand
b	the second operand

Returns

the product as fixed point number

fixed_to_int()

static uint16_t fixed_to_int ( fixed_t  value )

inlinestatic

Converts fixed point number to an integer.

Parameters

value

the fixed point number to convert

Returns

the rounded integer part of the fixed point number

init_linear_from_midi()

void init_linear_from_midi

(

struct linear_range *

config

)

Initializes a linear function to map from MIDI values to an arbitrary integer range.

Parameters

config

the configuration of the linear function to initialize

init_linear_to_midi()

void init_linear_to_midi

(

struct linear_range *

config

)

Initializes a linear function to map from an arbitrary integer range to MIDI values.

Parameters

config

the configuration of the linear function to initialize

linear_from_midi()

uint16_t linear_from_midi	(	const struct linear_range *	config,
		midi_value_t	midi_value
	)

Yields an integer in the configured range that corresponds to the given MIDI value.

Parameters

config	the configuration of the linear function
midi_value	the MIDI value to convert [0,127]

Returns

the input scaled to the configured range

linear_to_midi()

midi_value_t linear_to_midi	(	const struct linear_range *	config,
		uint16_t	input
	)

Yields the MIDI value [0,127] from a given integer in the configured range.

Parameters

config	the configuration of the linear function
input	the integer to convert to a MIDI value

Returns

the input scaled to the MIDI range [0,127]