/*************************************************************************
$Archive: /PACS/OnBoard/crc.c $
$Revision: 1.12 $  $Date: 2009/04/23 13:51:12 $  
$Author: amazy $ 
$Log: crc.c,v $
Revision 1.12  2009/04/23 13:51:12  amazy
6.029

 * 
 * 5     12/11/06 11:48a Amazy
 * introduced checksum in DMC HK
 * 
 * 4     11/12/06 11:04 Amazy
 * 
 * 11    3/14/06 4:31p Pacs Egse
 * Version 6.001
 * Cleaned and commented
*************************************************************************/

#ifdef SIMULATOR
#include "VirtuosoSim.h"
#endif

#include "crc.h"
#include "l_gendef.h"
#include "l_memory.h"

/*
IMPORTANT NOTE :
This file has been provided by IFSI.  It has been slightly modified to follow
our programming standards.
*/

/* AUTHOR : SPezzuto */
/* This  is  the  definition  of  the  polynomial for the checksum algorithm. */
/* According  to  the  PS-ICD  the  polynomial  is    X^16+X^12+X^5+1   which */
/* corresponds to 69665 (decimal) or 11021 (hex).                             */
#define TM_CRC_GENERATOR 0x00011021
int aCrcTable[256];

/* AUTHOR : SPezzuto */
/* This  is  the  function that initializes the table. It must be called once */
/* for all   (probably at startup).   By default the generator is equal to    */
/* TM_CRC_GENERATOR                                                           */
void InitCrcTable()
{
	int i;
	int j;
	int crc;
	
	for (i=0;i<256;i++) 
	{
		crc = i << 8;
		for (j=0;j<8;j++) 
		{
			if (crc & 0x00008000) 
			{
				crc = (crc << 1) ^ TM_CRC_GENERATOR;
			}
			else
			{
				crc = (crc << 1);
			}
		}
		aCrcTable[i] = crc & 0x0000FFFF;
	}
}



int Crc8(int data, int crc) 
{
  crc = aCrcTable[((crc >> 8)^data) & 0x000000FF] ^ (crc << 8);
  crc = crc & 0x0000FFFF;
  
  return crc;
}

int Crc16(int data, int crc) 
{
  crc = Crc8(data >> 8, crc);  
  return Crc8(data & 0x000000FF, crc);
}

int Crc32(int data, int crc)
{
	crc = Crc16((data >> 16) & 0xFFFF, crc);
	return Crc16(data & 0xFFFF, crc);
}

/*
FUNCTION : int GetChecksum(int* p_buffer, int size)
***************************************************

AUTHOR : AMazy

USE : 
Compute the checksum of the given buffer.

PARAMETERS:
int* p_buffer	: a pointer on a 32bits buffer
int size		: size of buffer (in 32bits words)

SEE ALSO :
"DpuRec.c"
*/
int GetChecksum(int* p_buffer, int size)
{
	int i=0;
	int crc = 0xFFFFFFFF;

#ifdef VERBOSE
	int* p_initialBuffer = p_buffer;
#endif


	for (; i < size; i++, p_buffer++)
	{
		crc = Crc8((*p_buffer >> 24) & 0x000000FF, crc);
		crc = Crc8((*p_buffer & 0x00FF0000) >> 16, crc);
		crc = Crc8((*p_buffer & 0x0000FF00) >> 8, crc);
		crc = Crc8(*p_buffer & 0x000000FF, crc);
	};

	return crc;
};


/*
FUNCTION : int GetChecksumInPram(int* p_buffer, int size)
*********************************************************

AUTHOR : AMazy

USE : 
Compute the checksum of the given buffer.

PARAMETERS:
int* p_buffer	: a pointer on a 48bits buffer
int size		: size of buffer (in 48bits words)

SEE ALSO :
"DpuRec.c"
*/
int GetChecksumInPram(int* p_buffer, int size)
{
	int i=0;
	int crc = 0xFFFFFFFF;

	T_UNSIGNED_32 temp32; 
	T_UNSIGNED_16 temp16; 

#ifdef VERBOSE
	int* p_initialBuffer = p_buffer;
#endif


	for (; i < size; i++, p_buffer++)
	{
#ifndef SIMULATOR
		temp32 = MEM_ReadPM32bitMSWord((T_UNSIGNED_32)p_buffer);
		temp16 = MEM_ReadPM16bitLSWord((T_UNSIGNED_32)p_buffer);
#endif //SIMULATOR
		crc = Crc8((temp32 >> 24) & 0x000000FF, crc);
		crc = Crc8((temp32 & 0x00FF0000) >> 16, crc);
		crc = Crc8((temp32 & 0x0000FF00) >> 8, crc);
		crc = Crc8(temp32 & 0x000000FF, crc);
		crc = Crc8((temp16 & 0x0000FF00) >> 8, crc);
		crc = Crc8(temp16 & 0x000000FF, crc);
	};

	return crc;
};