ecc-sw.c File Reference

Hamming ECC software implementation.

This file contains a software Hamming ECC implementation.

Copyright (c) 2012-2018 Microchip Technology Inc. and its subsidiaries.

#include "ecc-sw.h"

Functions
static void	compute256 (const uint8_t *data, uint8_t *code)
	Calculates the 22-bit hamming code for a 256-bytes block of data. More...
static uint32_t	count_bits_in_byte (uint8_t byte)
	Count and return the number of bits set to '1' in the given byte. More...
static uint32_t	count_bits_in_code256 (uint8_t *code)
	Count and return the number of bits set to '1' in the given hamming code. More...
void	hamming_compute_256x (const uint8_t *puc_data, uint32_t dw_size, uint8_t *puc_code)
	Computes 3-bytes hamming codes for a data block whose size is multiple of 256 bytes. More...
uint32_t	hamming_verify_256x (uint8_t *puc_data, uint32_t dw_size, const uint8_t *puc_code)
	Verify 3-bytes hamming codes for a data block whose size is multiple of 256 bytes. More...
static uint32_t	verify256 (uint8_t *puc_data, const uint8_t *puc_original_code)
	Verifies and corrects a 256-bytes block of data using the given 22-bits hamming code. More...

static void compute256 ( const uint8_t *  data, uint8_t *  code  )

static

Calculates the 22-bit hamming code for a 256-bytes block of data.

Parameters

data	Data buffer to calculate code for.
code	Pointer to a buffer where the code should be stored.

References count_bits_in_byte().

Referenced by hamming_compute_256x(), and verify256().

static uint32_t count_bits_in_byte ( uint8_t  byte )

static

Count and return the number of bits set to '1' in the given byte.

Parameters

byte	Byte to count.

Referenced by compute256(), and count_bits_in_code256().

static uint32_t count_bits_in_code256 ( uint8_t *  code )

static

Count and return the number of bits set to '1' in the given hamming code.

Parameters

code	Hamming code.

References count_bits_in_byte().

Referenced by verify256().

void hamming_compute_256x	(	const uint8_t *	puc_data,
		uint32_t	dw_size,
		uint8_t *	puc_code
	)

Computes 3-bytes hamming codes for a data block whose size is multiple of 256 bytes.

Each 256 bytes block gets its own code.

Parameters

puc_data	Pointer to data to compute code for.
dw_size	Data size in bytes.
puc_code	Pointer to codes buffer.

References compute256().

uint32_t hamming_verify_256x	(	uint8_t *	puc_data,
		uint32_t	dw_size,
		const uint8_t *	puc_code
	)

Verify 3-bytes hamming codes for a data block whose size is multiple of 256 bytes.

Each 256-bytes block is verified with its own code.

Parameters

puc_data	Pointer to data buffer to verify.
dw_size	Size of the data in bytes.
puc_code	Pointer to original codes.

Returns

0 if the data is correct, HAMMING_ERROR_SINGLE_BIT if one or more block(s) have had a single bit corrected, or either HAMMING_ERROR_ECC or HAMMING_ERROR_MULTIPLE_BITS.

References HAMMING_ERROR_SINGLE_BIT, and verify256().

static uint32_t verify256 ( uint8_t *  puc_data, const uint8_t *  puc_original_code  )

static

Verifies and corrects a 256-bytes block of data using the given 22-bits hamming code.

Parameters

puc_data	Pointer to data buffer to check.
puc_original_code	Pointer to hamming code to use for verifying the data.

Returns

0 if there is no error, otherwise returns a HAMMING_ERROR code.

References compute256(), count_bits_in_code256(), HAMMING_ERROR_ECC, HAMMING_ERROR_MULTIPLE_BITS, and HAMMING_ERROR_SINGLE_BIT.

Referenced by hamming_verify_256x().