sqrt.h

// Copyright 2009-2022 NTESS. Under the terms
// of Contract DE-NA0003525 with NTESS, the U.S.
// Government retains certain rights in this software.
//
// Copyright (c) 2009-2022, NTESS
// All rights reserved.
//
// This file is part of the SST software package. For license
// information, see the LICENSE file in the top level directory of the
// distribution.

#ifndef SST_CORE_MATH_SQRT_H
#define SST_CORE_MATH_SQRT_H

namespace SST {
namespace Math {

// Implements uint32_t square root based on algorithm from:
// Reference: http://en.wikipedia.org/wiki/Methods_of_computing_square_roots
static inline uint32_t
square_root(const uint32_t input)
{

    uint32_t op  = input;
    uint32_t res = 0;
    uint32_t one = 1uL << 30;

    while ( one > op ) {
        one >>= 2;
    }

    while ( one != 0 ) {
        if ( op >= res + one ) {
            op  = op - (res + one);
            res = res + 2 * one;
        }

        res >>= 1;
        one >>= 2;
    }

    return res;
};

} // namespace Math
} // namespace SST

#endif // SST_CORE_MATH_SQRT_H