samsung_new_ecc_for_512byte_256word.txt

为samsung Hamming code 的源码,该源码采用移位的方法,比一般的查表占用更少资源,是一种比较贴近硬件的c语言实现

/*****************************************************************************/
/*                                                                           */
/* PROJECT : SAMSUNG ECC                                                     */
/* FILE    : SAMSUNG_ECC.c                                                   */
/* PURPOSE : This file implements core ECC algorithms adopted				 */
/*           Hamming Error Correction and Detection Algorithm                */
/*                                                                           */
/*---------------------------------------------------------------------------*/
/*                                                                           */
/*        COPYRIGHT 2000-2004, SAMSUNG ELECTRONICS CO., LTD.                 */
/*                      ALL RIGHTS RESERVED                                  */
/*                                                                           */
/*   Permission is hereby granted to licensees of Samsung Electronics        */
/*   Co., Ltd. products to use or abstract this computer program for the     */
/*   sole purpose of implementing a product based on Samsung                 */
/*   Electronics Co., Ltd. products. No other rights to reproduce, use,      */
/*   or disseminate this computer program, whether in part or in whole,      */
/*   are granted.                                                            */
/*                                                                           */
/*   Samsung Electronics Co., Ltd. makes no representation or warranties     */
/*   with respect to the performance of this computer program, and           */
/*   specifically disclaims any responsibility for any damages,              */
/*   special or consequential, connected with the use of this program.       */
/*                                                                           */
/*---------------------------------------------------------------------------*/
/*                                                                           */
/* REVISION HISTORY                                                          */
/*                                                                           */
/*  13-NOV-2003 [Chang JongBaek] : 	first writing                            */
/*  03-MAR-2004 [ Kim YoungGon ] :  Second writing                           */
/*  03-MAR-2004 [  Lee JaeBum  ] :  Third writing                            */
/*---------------------------------------------------------------------------*/
/*                                                                           */
/* NOTES                                                                     */
/*                                                                           */
/* - Make ECC parity code of 512bytes(256words) and 3 bytes are represented  */
/*   And ECC compare & Correction code is also represented                   */
/*                                                                           */
/*****************************************************************************/
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>
#include "ecc.h"

#define	XMODE	8

/*****************************************************************************/
/* Address Types                                                             */
/*****************************************************************************/

typedef unsigned char *		address_t;			/* address (pointer) */
typedef unsigned long		address_value_t;	/* address (for calculation) */

/*****************************************************************************/
/* Integer Types                                                             */
/*****************************************************************************/

typedef unsigned long		uint32_t;			/* unsigned 4 byte integer */
typedef signed long			int32_t;			/* signed 4 byte integer */
typedef unsigned short		uint16_t;			/* unsigned 2 byte integer */
typedef signed short		int16_t;			/* signed 2 byte integer */
typedef unsigned char		uint8_t;			/* unsigned 1 byte integer */
typedef signed char			int8_t;				/* signed 1 byte integer */

typedef enum {
	ECC_NO_ERROR			= 0,		/* no error */
	ECC_CORRECTABLE_ERROR	= 1,		/* one bit data error */
	ECC_ECC_ERROR			= 2,		/* one bit ECC error */
	ECC_UNCORRECTABLE_ERROR	= 3			/* uncorrectable error */
} eccdiff_t;

/*****************************************************************************/
/*                                                                           */
/* NAME                                                                      */
/*		make_ecc_512                                                         */
/* DESCRIPTION                                                               */
/*		This function generates 3 byte ECC for 512 byte data.                */
/*      (Software ECC)                                                       */
/* PARAMETERS                                                                */
/*		ecc_buf			the location where ECC should be stored              */
/*		data_buf		given data                                           */
/* RETURN VALUES                                                             */
/*		none                                                                 */
/*                                                                           */
/*****************************************************************************/
#if (XMODE == 8)
void make_ecc_512(uint8_t * ecc_buf, uint8_t * data_buf)
#else
void make_ecc_512(uint16_t * ecc_buf, uint16_t * data_buf)
#endif
{
	
    uint32_t	i, ALIGN_FACTOR; 
	uint32_t	tmp;
	uint32_t	uiparity = 0;
	uint32_t	parityCol, ecc = 0;
	uint32_t	parityCol4321 = 0, parityCol4343 = 0, parityCol4242 = 0, parityColTot = 0;
	uint32_t	*Data;
	uint32_t	Xorbit=0;

	ALIGN_FACTOR = (uint32_t)data_buf % 4 ;
	Data = (uint32_t *)(data_buf + ALIGN_FACTOR);

	for( i = 0; i < 16; i++)
	{
		parityCol = *Data++; 
		tmp = *Data++; parityCol ^= tmp; parityCol4242 ^= tmp;
		tmp = *Data++; parityCol ^= tmp; parityCol4343 ^= tmp;
		tmp = *Data++; parityCol ^= tmp; parityCol4343 ^= tmp; parityCol4242 ^= tmp;
		tmp = *Data++; parityCol ^= tmp; parityCol4321 ^= tmp;
		tmp = *Data++; parityCol ^= tmp; parityCol4242 ^= tmp; parityCol4321 ^= tmp;
		tmp = *Data++; parityCol ^= tmp; parityCol4343 ^= tmp; parityCol4321 ^= tmp;
		tmp = *Data++; parityCol ^= tmp; parityCol4242 ^= tmp; parityCol4343 ^= tmp; parityCol4321 ^= tmp;

		parityColTot ^= parityCol;

		tmp = (parityCol >> 16) ^ parityCol;
		tmp = (tmp >> 8) ^ tmp;
		tmp = (tmp >> 4) ^ tmp;
		tmp = ((tmp >> 2) ^ tmp) & 0x03;
		if ((tmp == 0x01) || (tmp == 0x02))
		{
			uiparity ^= i;
			Xorbit ^= 0x01;
		}
	}

#if (XMODE == 8)
	tmp = (parityCol4321 >> 16) ^ parityCol4321;
	tmp = (tmp << 8) ^ tmp;
	tmp = (tmp >> 4) ^ tmp;
	tmp = (tmp >> 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x200;	// p128
#else
	tmp = (parityCol4321 >> 16) ^ parityCol4321;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp << 4) ^ tmp;
	tmp = (tmp << 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x80;	// p128
#endif
#if (XMODE == 8)
	tmp = (parityCol4343 >> 16) ^ parityCol4343;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp << 4) ^ tmp;
	tmp = (tmp << 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x80;	// p64
#else
	tmp = (parityCol4343 >> 16) ^ parityCol4343;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp << 4) ^ tmp;
	tmp = (tmp >> 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x20;	// p64
#endif
#if (XMODE == 8)
	tmp = (parityCol4242 >> 16) ^ parityCol4242;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp << 4) ^ tmp;
	tmp = (tmp >> 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x20;	// p32
#else
	tmp = (parityCol4242 >> 16) ^ parityCol4242;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp >> 4) ^ tmp;
	tmp = (tmp << 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x08;	// p32
#endif
#if (XMODE == 8)
	tmp = parityColTot & 0xFFFF0000;
	tmp = tmp >> 16;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp >> 4) ^ tmp;
	tmp = (tmp << 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x08;	// p16
#else
	tmp = parityColTot & 0xFFFF0000;
	tmp = tmp >> 16;
	tmp = (tmp >> 8) ^ tmp;
	tmp = (tmp >> 4) ^ tmp;
	tmp = (tmp >> 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x02;	// p16
#endif
#if (XMODE == 8)
	tmp = parityColTot & 0xFF00FF00;
	tmp = (tmp >> 16) ^ tmp;
	tmp = (tmp >> 8);
	tmp = (tmp >> 4) ^ tmp;
	tmp = (tmp >> 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x02;	// p8
#else
	tmp = parityColTot & 0xFF00FF00;
	tmp = (tmp << 16) ^ tmp;
	tmp = (tmp >> 8);
	tmp = (tmp << 4) ^ tmp;
	tmp = (tmp << 2) ^ tmp;
	ecc |= ((tmp << 1) ^ tmp) & 0x800000;	// p8
#endif