bit_field.c File Reference

Bit field manipulation. More...

#include "bit_field.h"
#include "sark.h"

Macros
#define	__use(x)   ((void) (x))
	The use macro allows us to "pretend" to use a variable in a function; this is useful if we run with -Wextra set for extra warnings.

Functions
static void	print_bit_field_entry (uint32_t e)
	This function prints out an individual word of a bit_field, as a sequence of ones and zeros.
void	print_bit_field_bits (const bit_field_t restrict b, size_t s)
	This function prints out an entire bit_field, as a sequence of ones and zeros.
void	print_bit_field (const bit_field_t restrict b, size_t s)
	This function prints out an entire bit_field, as a sequence of hexadecimal numbers, one per line.
void	random_bit_field (bit_field_t restrict b, size_t s)
	Generates a random bit_field for testing purposes.
bit_field_t	bit_field_alloc (uint32_t n_atoms)
	allocates a bit_field_t object

Detailed Description

Bit field manipulation.

A bit field is a vector of machine words which is treated as a vector of bits.

For SpiNNaker each machine word is 32 bits, and so a bit_field for each neuron (assuming 256 neurons) would be 8 words long.

The API includes:

• bit_field_test() returns true of false depending on whether bit n is set or clear
• bit_field_set() / bit_field_clear() used to set or clear bit n
• not_bit_field() logically inverts a bit field of size s.
• and_bit_fields() / or_bit_fields() logically ands/ors two bit_fields together. Requires size.
• clear_bit_field() / set_bit_field() Initializes bit_field with all false (= clear) or true (= set). Requires size.

There are also support functions for:

• printing
• randomly setting up a bit field

Author

Dave Lester (david.nosp@m..r.l.nosp@m.ester.nosp@m.@man.nosp@m.chest.nosp@m.er.a.nosp@m.c.uk), Jamie Knight (knigh.nosp@m.tj@c.nosp@m.s.man.nosp@m..ac..nosp@m.uk)

Copyright

Copyright (c) Dave Lester, Jamie Knight and The University of Manchester, 2013. All rights reserved. SpiNNaker Project Advanced Processor Technologies Group School of Computer Science The University of Manchester Manchester M13 9PL, UK

Date

12 December, 2013

Macro Definition Documentation

__use

#define __use

(

x

)

((void) (x))

The use macro allows us to "pretend" to use a variable in a function; this is useful if we run with -Wextra set for extra warnings.

Parameters

x	The name of the argument to mark as used

Function Documentation

print_bit_field_entry()

static void print_bit_field_entry ( uint32_t  e )

inlinestatic

This function prints out an individual word of a bit_field, as a sequence of ones and zeros.

Parameters

[in]

e

The word of a bit_field to be printed.

print_bit_field_bits()

void print_bit_field_bits	(	const bit_field_t restrict	b,
		size_t	s
	)

This function prints out an entire bit_field, as a sequence of ones and zeros.

Parameters

[in]	b	The sequence of words representing a bit_field.
[in]	s	The size of the bit_field.

print_bit_field()

void print_bit_field	(	const bit_field_t restrict	b,
		size_t	s
	)

This function prints out an entire bit_field, as a sequence of hexadecimal numbers, one per line.

Parameters

[in]	b	The sequence of words representing a bit_field.
[in]	s	The size of the bit_field.

random_bit_field()

void random_bit_field	(	bit_field_t restrict	b,
		size_t	s
	)

Generates a random bit_field for testing purposes.

Parameters

[in]	b	The sequence of words representing a bit_field.
[in]	s	The size of the bit_field.

bit_field_alloc()

bit_field_t bit_field_alloc

(

uint32_t

n_atoms

)

allocates a bit_field_t object

Parameters

[in]

n_atoms

the number of atoms to cover with this bitfield

Returns

the allocated bitfield