CSCTMBTrailer.cc

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#include "EventFilter/CSCRawToDigi/interface/CSCTMBTrailer.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include <iostream>
#include <cassert>

CSCTMBTrailer::CSCTMBTrailer(int wordCount, int firmwareVersion) : theFirmwareVersion(firmwareVersion) {
  //FIXME do firmware version
  theData[0] = 0x6e0c;
  // all the necessary lines from this thing first
  wordCount += 5;
  // see if we need thePadding to make a multiple of 4
  thePadding = 0;

  if (wordCount % 4 == 2) {
    theData[1] = 0x2AAA;
    theData[2] = 0x5555;
    thePadding = 2;
    wordCount += thePadding;
  }
  // the next four words start with 11011, or a D
  for (int i = 1; i < 5; ++i) {
    theData[i + thePadding] = 0xD800;
  }
  theData[de0fOffset()] = 0xde0f;
  // word count excludes the trailer
  theData[4 + thePadding] |= wordCount;
}

CSCTMBTrailer::CSCTMBTrailer(const uint16_t* buf, unsigned short int firmwareVersion)
    : theFirmwareVersion(firmwareVersion) {
  // take a little too much, maybe
  memcpy(theData, buf, 14);
  switch (firmwareVersion) {
    case 2006:
      // if there's padding, there'll be a de0f in the 6th word.
      // If not, you'll be in CFEB-land, where they won't be de0f.
      thePadding = (theData[5] == 0xde0f ? 2 : 0);
      break;
    case 2007:
      // =VB= check for 1st word to be 0xDE0F, then check 3rd
      // to handle freaky cases of double 0xDE0F signatures in trailer
      thePadding = (theData[1] == 0xde0f ? 0 : (theData[3] == 0xde0f ? 2 : 0));
      //    thePadding = (theData[3] == 0xde0f ? 2 : 0);
      break;
    default:
      edm::LogError("CSCTMBTrailer|CSCRawToDigi") << "failed to contruct: firmware version is bad/not defined!";
  }
}

unsigned int CSCTMBTrailer::crc22() const {
  return (theData[crcOffset()] & 0x07ff) + ((theData[crcOffset() + 1] & 0x07ff) << 11);
}

void CSCTMBTrailer::setCRC(int crc) {
  theData[crcOffset()] |= (crc & 0x07ff);
  theData[crcOffset() + 1] |= ((crc >> 11) & 0x07ff);
}

int CSCTMBTrailer::wordCount() const { return theData[4 + thePadding] & 0x7ff; }

void CSCTMBTrailer::selfTest() {
  CSCTMBTrailer trailer(104, 2006);
  unsigned int crc = 0xb00b1;
  trailer.setCRC(crc);
  assert(trailer.crc22() == 0xb00b1);

  CSCTMBTrailer trailer2(104, 2007);
  crc = 0xb00b1;
  trailer2.setCRC(crc);
  assert(trailer2.crc22() == 0xb00b1);
}