Simple near-hardware-speed floored square root for 64-bit integers

IntegerSquareRoot.java

/* Sometimes, taking the floored square root of a 64-bit integer is needed.
   In order to gain the speed of hardware square root, 64-bit integers must be converted
     to 53-bit mantissa doubles.
   This can cause incorrect results due to loss of precision.
   However, the floor of the square root produced will be either the correct
     floored square root or the next higher integer.
     For reasoning, see http://apps.topcoder.com/forums/?module=Thread&threadID=695233
   So, we can simply:
     1) Convert to double.
     2) Use hardware square root.
     3) Convert to long.
     4) If the square of the result is higher than the input value, subtract one from the result.
     5) Return the result.
*/

public static final long fastFlooredSqrt(final long value) {
    long result = (long) Math.sqrt((double) value);
    if (result*result > value) result--;
    return result;
}