@Override
  public long expOperationGasCost(final int numBytes) {
    return expOperationByteGasCost() * numBytes + EXP_OPERATION_BASE_GAS_COST;
  }
Returns the gas cost for a byte in the {@link ExpOperation}.

@return the gas cost for a byte in the exponent operation
evm/src/main/java/org/hyperledger/besu/evm/gascalculator/FrontierGasCalculator.java