GEMVFAT.cc

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#include "DataFormats/GEMDigi/interface/GEMVFAT.h"
#include <iostream>

GEMVFAT::GEMVFAT() : ver_(0), phiPos_(0), fw_(0), sw_(0), tw_(0) {}

GEMVFAT::GEMVFAT(const int vfatVer,
                 const uint16_t BC,
                 const uint32_t EC,
                 const uint16_t chipID,
                 const uint64_t lsDatas,
                 const uint64_t msDatas) {
  // this constructor only used for packing sim digis
  VFATfirst fw{0};
  VFATsecond sw{0};
  VFATthird tw{0};

  fw.header = 0x1E;

  if (vfatVer == 3) {
    fw.bc = BC;
    fw.ec = EC;
    fw.pos = chipID;
  } else {
    fw.chipID = chipID;
    fw.b1110 = 14;
    fw.b1100 = 12;
    fw.b1010 = 10;
    fw.ecV2 = EC;
    fw.bcV2 = BC;
  }

  sw.lsData1 = lsDatas >> 48;
  tw.lsData2 = lsDatas & 0x0000ffffffffffff;

  fw.msData1 = msDatas >> 48;
  sw.msData2 = msDatas & 0x0000ffffffffffff;
  ver_ = vfatVer;

  fw_ = fw.word;
  sw_ = sw.word;
  tw_ = tw.word;
  // checkCRC only works after words are set
  // checkCRC not yet implemented for v3
  tw.crc = checkCRC();
  // once crc is found, save new third word
  tw_ = tw.word;
}

uint8_t GEMVFAT::quality() {
  uint8_t q = 0;
  if (ver_ == 2) {
    if (VFATthird{tw_}.crc != checkCRC())
      q = 1;
    if (VFATfirst{fw_}.b1010 != 10)
      q |= 1UL << 1;
    if (VFATfirst{fw_}.b1100 != 12)
      q |= 1UL << 2;
    if (VFATfirst{fw_}.b1110 != 14)
      q |= 1UL << 3;
  }
  // quality test not yet implemented in v3
  return q;
}

uint16_t GEMVFAT::crc_cal(uint16_t crc_in, uint16_t dato) {
  uint16_t v = 0x0001;
  uint16_t mask = 0x0001;
  uint16_t d = 0x0000;
  uint16_t crc_temp = crc_in;
  unsigned char datalen = 16;
  for (int i = 0; i < datalen; i++) {
    if (dato & v)
      d = 0x0001;
    else
      d = 0x0000;
    if ((crc_temp & mask) ^ d)
      crc_temp = crc_temp >> 1 ^ 0x8408;
    else
      crc_temp = crc_temp >> 1;
    v <<= 1;
  }
  return crc_temp;
}

uint16_t GEMVFAT::checkCRC() {
  uint16_t vfatBlockWords[12];
  vfatBlockWords[11] = ((0x000f & VFATfirst{fw_}.b1010) << 12) | VFATfirst{fw_}.bcV2;
  vfatBlockWords[10] =
      ((0x000f & VFATfirst{fw_}.b1100) << 12) | ((0x00ff & VFATfirst{fw_}.ecV2) << 4) | (0x000f & VFATfirst{fw_}.flag);
  vfatBlockWords[9] = ((0x000f & VFATfirst{fw_}.b1110) << 12) | VFATfirst{fw_}.chipID;
  vfatBlockWords[8] = (0xffff000000000000 & msData()) >> 48;
  vfatBlockWords[7] = (0x0000ffff00000000 & msData()) >> 32;
  vfatBlockWords[6] = (0x00000000ffff0000 & msData()) >> 16;
  vfatBlockWords[5] = (0x000000000000ffff & msData());
  vfatBlockWords[4] = (0xffff000000000000 & lsData()) >> 48;
  vfatBlockWords[3] = (0x0000ffff00000000 & lsData()) >> 32;
  vfatBlockWords[2] = (0x00000000ffff0000 & lsData()) >> 16;
  vfatBlockWords[1] = (0x000000000000ffff & lsData());

  uint16_t crc_fin = 0xffff;
  for (int i = 11; i >= 1; i--) {
    crc_fin = crc_cal(crc_fin, vfatBlockWords[i]);
  }
  return crc_fin;
}