Re: integral to floating point conversion

[ketmar via Digitalmars-d]

On Saturday, 2 July 2016 at 20:17:59 UTC, Andrei Alexandrescu 
wrote:
So what's the fastest way to figure that an integral is 
convertible to a floating point value precisely (i.e. no other 
integral converts to the same floating point value)? Thanks! -- 
Andrei

bool isConvertible(T) (long n) if (is(T == float) || is(T == 
double)) {
  pragma(inline, true);
  static if (is(T == float)) {
    return (((n+(n>>63))^(n>>63))&0xffffffffff000000UL) == 0;
  } else {
    return (((n+(n>>63))^(n>>63))&0xffe0000000000000UL) == 0;
  }
}