Question

Is there a function in c# that takes two 32 bit integers (int) and returns a single 64 bit one (long)?

Sounds like there should be a simple way to do this, but I couldn’t find a solution.

Answer 1

Try the following

public long MakeLong(int left, int right) {
  //implicit conversion of left to a long
  long res = left;

  //shift the bits creating an empty space on the right
  // ex: 0x0000CFFF becomes 0xCFFF0000
  res = (res << 32);

  //combine the bits on the right with the previous value
  // ex: 0xCFFF0000 | 0x0000ABCD becomes 0xCFFFABCD
  res = res | (long)(uint)right; //uint first to prevent loss of signed bit

  //return the combined result
  return res;
}