Accelerated Viterbi decoder implementation. More...

#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "config.h"
#include <osmocom/core/conv.h>

Data Structures
struct	vtrellis

struct	vdecoder

Macros
#define	BIT2NRZ(REG, N) (((REG >> N) & 0x01) * 2 - 1) * -1

#define	NUM_STATES(K) (K == 7 ? 64 : 16)

#define	INIT_POINTERS(simd)

Functions
	__attribute__ ((visibility("hidden")))

static int	conv_code_recursive (const struct osmo_conv_code *code)

static unsigned	vstate_lshift (unsigned reg, int k, int val)

static unsigned	bitswap2 (unsigned v)

static unsigned	bitswap3 (unsigned v)

static unsigned	bitswap4 (unsigned v)

static unsigned	bitswap5 (unsigned v)

static unsigned	bitswap6 (unsigned v)

static unsigned	bitswap (unsigned v, unsigned n)

static unsigned	gen_output (struct vstate state, int val, const struct osmo_conv_code code)

static int	gen_state_info (uint8_t val, unsigned reg, int16_t output, const struct osmo_conv_code *code)

static unsigned	gen_recursive_output (struct vstate state, uint8_t val, unsigned reg, const struct osmo_conv_code *code, int pos)

static int	gen_recursive_state_info (uint8_t val, unsigned reg, int16_t output, const struct osmo_conv_code *code)

static void	free_trellis (struct vtrellis *trellis)

static int	generate_trellis (struct vdecoder dec, const struct osmo_conv_code code)

static void	_traceback (struct vdecoder dec, unsigned state, uint8_t out, int len)

static void	_traceback_rec (struct vdecoder dec, unsigned state, uint8_t out, int len)

static int	traceback (struct vdecoder dec, uint8_t out, int term, int len)

static void	vdec_deinit (struct vdecoder *dec)

static int	vdec_init (struct vdecoder dec, const struct osmo_conv_code code)

static int	depuncture (const int8_t in, const int punc, int8_t *out, int len)

static void	forward_traverse (struct vdecoder dec, const int8_t seq)

static int	conv_decode (struct vdecoder dec, const int8_t seq, const int punc, uint8_t out, int len, int term)

static void	osmo_conv_init (void)

int	osmo_conv_decode_acc (const struct osmo_conv_code code, const sbit_t input, ubit_t *output)

Variables
static int	init_complete = 0

Detailed Description

Accelerated Viterbi decoder implementation.

Macro Definition Documentation

◆ BIT2NRZ

#define BIT2NRZ	(	REG,
		N
	)	(((REG >> N) & 0x01) * 2 - 1) * -1

◆ INIT_POINTERS

#define INIT_POINTERS ( simd )

Value:

{ \
        osmo_conv_metrics_k5_n2 = osmo_conv_##simd##_metrics_k5_n2; \
        osmo_conv_metrics_k5_n3 = osmo_conv_##simd##_metrics_k5_n3; \
        osmo_conv_metrics_k5_n4 = osmo_conv_##simd##_metrics_k5_n4; \
        osmo_conv_metrics_k7_n2 = osmo_conv_##simd##_metrics_k7_n2; \
        osmo_conv_metrics_k7_n3 = osmo_conv_##simd##_metrics_k7_n3; \
        osmo_conv_metrics_k7_n4 = osmo_conv_##simd##_metrics_k7_n4; \
        vdec_malloc = &osmo_conv_##simd##_vdec_malloc; \
        vdec_free = &osmo_conv_##simd##_vdec_free; \
}

◆ NUM_STATES

#define NUM_STATES ( K ) (K == 7 ? 64 : 16)

Function Documentation

◆ attribute()

__attribute__ ( (visibility("hidden")) )

◆ _traceback()

static void _traceback	(	struct vdecoder *	dec,
		unsigned	state,
		uint8_t *	out,
		int	len
	)

static

References vdecoder::k, len(), vdecoder::paths, vdecoder::trellis, vtrellis::vals, and vstate_lshift().

Referenced by traceback().

◆ _traceback_rec()

static void _traceback_rec	(	struct vdecoder *	dec,
		unsigned	state,
		uint8_t *	out,
		int	len
	)

static

References vdecoder::k, len(), vdecoder::paths, vdecoder::trellis, vtrellis::vals, and vstate_lshift().

Referenced by traceback().

◆ bitswap()

static unsigned bitswap	(	unsigned	v,
		unsigned	n
	)

static

References bitswap2(), bitswap3(), bitswap4(), bitswap5(), bitswap6(), and n.

Referenced by gen_output(), and gen_recursive_output().

◆ bitswap2()

static unsigned bitswap2 ( unsigned v )

inlinestatic

Referenced by bitswap().

◆ bitswap3()

static unsigned bitswap3 ( unsigned v )

inlinestatic

Referenced by bitswap().

◆ bitswap4()

static unsigned bitswap4 ( unsigned v )

inlinestatic

Referenced by bitswap().

◆ bitswap5()

static unsigned bitswap5 ( unsigned v )

inlinestatic

Referenced by bitswap().

◆ bitswap6()

static unsigned bitswap6 ( unsigned v )

inlinestatic

Referenced by bitswap().

◆ conv_code_recursive()

static int conv_code_recursive ( const struct osmo_conv_code * code )

inlinestatic

References osmo_conv_code::next_term_output.

Referenced by vdec_init().

◆ conv_decode()

static int conv_decode	(	struct vdecoder *	dec,
		const int8_t *	seq,
		const int *	punc,
		uint8_t *	out,
		int	len,
		int	term
	)

static

References CONV_TERM_TAIL_BITING, depuncture(), forward_traverse(), len(), vdecoder::len, vdecoder::n, and traceback().

Referenced by osmo_conv_decode_acc().

◆ depuncture()

static int depuncture	(	const int8_t *	in,
		const int *	punc,
		int8_t *	out,
		int	len
	)

static

References len(), and n.

Referenced by conv_decode().

◆ forward_traverse()

static void forward_traverse	(	struct vdecoder *	dec,
		const int8_t *	seq
	)

static

References vdecoder::intrvl, vdecoder::len, vdecoder::metric_func, vdecoder::n, vtrellis::outputs, vdecoder::paths, vtrellis::sums, and vdecoder::trellis.

Referenced by conv_decode().

◆ free_trellis()

static void free_trellis ( struct vtrellis * trellis )

static

References vtrellis::outputs, vtrellis::sums, and vtrellis::vals.

Referenced by generate_trellis(), and vdec_deinit().

◆ gen_output()

static unsigned gen_output	(	struct vstate *	state,
		int	val,
		const struct osmo_conv_code *	code
	)

static

References bitswap(), osmo_conv_code::K, osmo_conv_code::N, and osmo_conv_code::next_output.

Referenced by gen_state_info().

◆ gen_recursive_output()

static unsigned gen_recursive_output	(	struct vstate *	state,
		uint8_t *	val,
		unsigned	reg,
		const struct osmo_conv_code *	code,
		int	pos
	)

static

References bitswap(), osmo_conv_code::K, osmo_conv_code::N, osmo_conv_code::next_output, osmo_conv_code::next_term_output, and vstate_lshift().

Referenced by gen_recursive_state_info().

◆ gen_recursive_state_info()

static int gen_recursive_state_info	(	uint8_t *	val,
		unsigned	reg,
		int16_t *	output,
		const struct osmo_conv_code *	code
	)

static

References BIT2NRZ, gen_recursive_output(), osmo_conv_code::K, osmo_conv_code::N, osmo_conv_code::next_output, NUM_STATES, and vstate_lshift().

Referenced by generate_trellis().

◆ gen_state_info()

static int gen_state_info	(	uint8_t *	val,
		unsigned	reg,
		int16_t *	output,
		const struct osmo_conv_code *	code
	)

static

References BIT2NRZ, gen_output(), osmo_conv_code::K, osmo_conv_code::N, and vstate_lshift().

Referenced by generate_trellis().

◆ generate_trellis()

static int generate_trellis	(	struct vdecoder *	dec,
		const struct osmo_conv_code *	code
	)

static

For termination other than tail-biting, initialize the zero state as the encoder starting state. Initialize with the maximum accumulated sum at length equal to the constraint length.

References CONV_TERM_TAIL_BITING, free_trellis(), gen_recursive_state_info(), gen_state_info(), osmo_conv_code::K, osmo_conv_code::N, NUM_STATES, vtrellis::num_states, vtrellis::outputs, vdecoder::recursive, vtrellis::sums, osmo_conv_code::term, vdecoder::trellis, and vtrellis::vals.

Referenced by vdec_init().

◆ osmo_conv_init()

static void osmo_conv_init ( void )

static

Usage of curly braces is mandatory, because we use multi-line define.

References init_complete, INIT_POINTERS, and sse41_supported.

Referenced by osmo_conv_decode_acc().

◆ traceback()

static int traceback	(	struct vdecoder *	dec,
		uint8_t *	out,
		int	term,
		int	len
	)

static

References _traceback(), _traceback_rec(), CONV_TERM_FLUSH, CONV_TERM_TAIL_BITING, vdecoder::k, len(), vdecoder::len, vtrellis::num_states, vdecoder::paths, vdecoder::recursive, vtrellis::sums, vdecoder::trellis, and vstate_lshift().

Referenced by conv_decode().

◆ vdec_deinit()

static void vdec_deinit ( struct vdecoder * dec )

static

References free_trellis(), vdecoder::paths, and vdecoder::trellis.

Referenced by osmo_conv_decode_acc(), and vdec_init().

◆ vdec_init()

static int vdec_init	(	struct vdecoder *	dec,
		const struct osmo_conv_code *	code
	)

static

References conv_code_recursive(), CONV_TERM_FLUSH, generate_trellis(), if(), vdecoder::intrvl, osmo_conv_code::K, vdecoder::k, osmo_conv_code::len, vdecoder::len, vdecoder::metric_func, osmo_conv_code::N, vdecoder::n, NUM_STATES, vdecoder::paths, vdecoder::recursive, osmo_conv_code::term, and vdec_deinit().

Referenced by osmo_conv_decode_acc().

◆ vstate_lshift()

static unsigned vstate_lshift	(	unsigned	reg,
		int	k,
		int	val
	)

static

References k.

Referenced by _traceback(), _traceback_rec(), gen_recursive_output(), gen_recursive_state_info(), gen_state_info(), and traceback().

Variable Documentation

◆ init_complete

int init_complete = 0

static

Referenced by osmo_conv_decode_acc(), and osmo_conv_init().

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ BIT2NRZ

◆ INIT_POINTERS

◆ NUM_STATES

Function Documentation

◆ __attribute__()

◆ _traceback()

◆ _traceback_rec()

◆ bitswap()

◆ bitswap2()

◆ bitswap3()

◆ bitswap4()

◆ bitswap5()

◆ bitswap6()

◆ conv_code_recursive()

◆ conv_decode()

◆ depuncture()

◆ forward_traverse()

◆ free_trellis()

◆ gen_output()

◆ gen_recursive_output()

◆ gen_recursive_state_info()

◆ gen_state_info()

◆ generate_trellis()

◆ osmo_conv_init()

◆ traceback()

◆ vdec_deinit()

◆ vdec_init()

◆ vstate_lshift()

Variable Documentation

◆ init_complete

◆ attribute()