Microcontrollers Course Homework

stm32f10x_crc.c

#define bytes_to_long(a,b,c,d) ( ((d) << 24) | ((c) << 16) | ((b) << 8) | (a) )

/**                                                                                                                                                                       
  * @brief  Computes the 32-bit CRC of a given buffer of data word(32-bit).                                                                                               
  * @param  pBuffer: pointer to the buffer containing the data to be computed                                                                                             
  * @param  BufferLength: length of the buffer to be computed                                                                                                             
  * @retval 32-bit CRC                                                                                                                                                    
  */

uint32_t CRC_CalcBlockCRC(uint8_t pBuffer[], uint32_t BufferLength)
{
  uint32_t index = 0;
  uint8_t a, b, c, d;

  for(index = 0; index + 3 < BufferLength; index += 4)
  {
    a = pBuffer[index];
    b = pBuffer[index + 1];
    c = pBuffer[index + 2];
    d = pBuffer[index + 3];
    CRC->DR = bytes_to_long(a , b, c, d);
  }
  a = index < BufferLength ? pBuffer[index++] : 0;
  b = index < BufferLength ? pBuffer[index++] : 0;
  c = index < BufferLength ? pBuffer[index++] : 0;
  d = index < BufferLength ? pBuffer[index++] : 0;
  CRC->DR = bytes_to_long(a, b, c, d);

  return (CRC->DR);
}