TMS570LC4357: CRC Algorithm

#define CRC_CTRL0     (*(volatile uint32 *)0xFE000000U)
#define CRC_CTRL2     (*(volatile uint32 *)0xFE000010U)
#define CRC_SIGREG    (*(volatile uint64 *)0xFE000060U)

/* Function from SafeTI Diagnostic Library (sl_misc.c) */
/*SAFETYMCUSW 61 D MR: 8.10,8.11 <APPROVED> Comment_1*/
uint64 SL_CRC_Calculate (uint64* startAddr, const uint32 count64)
{
  volatile uint32 count = 0u; /* volatile in order to prevent from being optimised */

  CRC_CTRL0 |= 0x00000001U; /* Reset the CRC Module */
  CRC_CTRL0 &= 0xFFFFFFFEU;
  CRC_CTRL2 |= 0x00000003U; /* Configure to Full CPU Mode */

  /*SAFETYMCUSW 134 S MR: 12.2 <APPROVED> Comment_5*/
  /*SAFETYMCUSW 134 S MR: 12.2 <APPROVED> Comment_5*/
  for (count=0u; count < count64; count++) {
    /*SAFETYMCUSW 45 D MR:21.1 <APPROVED> Comment_2*/
    /*SAFETYMCUSW 93 S MR: 6.1,6.2,10.1,10.2,10.3,10.4 <APPROVED> "LDRA Tool issue" */
    CRC_SIGREG = (uint64)(*startAddr);
    /*SAFETYMCUSW 45 D MR:21.1 <APPROVED> Comment_2*/
    /*SAFETYMCUSW 567 S MR:17.1,17.4 <APPROVED> "Pointer increment needed" */
    startAddr++;
  }
    return(CRC_SIGREG);
}

/* Example for manual implementation by Richard Burke */
typedef uint64 crc_t;
crc_t crc_update_word(crc_t crc, crc_t data)
{
    int i, j;
    crc_t nextCrc = 0;
    // for i in 63 to 0 loop
    for(i = 63; i >= 0; i--)
    {
        // NEXT_CRC_VAL(0) := CRC_VAL(63) xor DATA(i);
        nextCrc = (nextCrc & (crc_t)0xfffffffffffffffe) | ((crc >> 63) ^ (data >> i));
        // for j in 1 to 63 loop
        for(j = 1; j < 64; j++)
        {
            //case j is
            // when 1|3|4 =>
            if(j == 1 || j == 3 || j == 4)
            {
                // NEXT_CRC_VAL(j) := CRC_VAL(j - 1) xor CRC_VAL(63) xor DATA(i);
                nextCrc = (nextCrc & ~((crc_t)1 << j)) | ((((crc >> (j-1)) ^ (crc >> 63) ^ (data >> i)) & 1) << j);
            }
            else
            { // when others =>
                // NEXT_CRC_VAL(j) := CRC_VAL(j - 1);
                nextCrc = (nextCrc & ~((crc_t)1 << j)) | (((crc >> (j-1)) & 1) << j);
            }
            // end case;
        } // end loop;
        crc = nextCrc;
    } // end loop

    return crc;
}

void crc_test(void)
{
  uint64 crc_test_value = 0x8DF8A32C74B91F3E;

  uint64 result_crc_manual = 0U;
  uint64 result_crc_safe_ti_lib = 0U;
  uint64 result_crc_test1 = 0U;
  uint64 result_crc_test2 = 0U;

  crcInit();  /* Sets everything to zero and enables Full CPU Mode */

  result_crc_manual = crc_update_word(0U, crc_test_value);

  result_crc_safe_ti_lib = SL_CRC_Calculate(&crc_test_value, 1U);

  /* test1: words not swapped */
  crcInit();
  crcREG1->PSA_SIGREGH1 = (uint32)(crc_test_value >> 32);
  crcREG1->PSA_SIGREGL1 = (uint32)crc_test_value;
  result_crc_test1 = crcGetPSASig(crcREG1, 0);

  /* test2: words swapped */
  crcInit();
  crcREG1->PSA_SIGREGH1 = (uint32)crc_test_value;
  crcREG1->PSA_SIGREGL1 = (uint32)(crc_test_value >> 32);
  result_crc_test2 = crcGetPSASig(crcREG1, 0);

  while(1);
}