Function IntSqrt

src/core/math_func.cpp:42–64

* Compute the integer square root. * @param num Radicand. * @return Rounded integer square root. * @note Algorithm taken from http://en.wikipedia.org/wiki/Methods_of_computing_square_roots */

 * @note Algorithm taken from http://en.wikipedia.org/wiki/Methods_of_computing_square_roots
 */
uint32_t IntSqrt(uint32_t num)
{
	uint32_t res = 0;
	uint32_t bit = 1UL << 30; // Second to top bit number.

	/* 'bit' starts at the highest power of four <= the argument. */
	while (bit > num) bit >>= 2;

	while (bit != 0) {
		if (num >= res + bit) {
			num -= res + bit;
			res = (res >> 1) + bit;
		} else {
			res >>= 1;
		}
		bit >>= 2;
	}

	/* Arithmetic rounding to nearest integer. */
	if (num > res) res++;

	return res;
}