| // SPDX-License-Identifier: GPL-2.0 |
| * Copyright (C) 2013 Davidlohr Bueso <davidlohr.bueso@hp.com> |
| * Based on the shift-and-subtract algorithm for computing integer |
| * square root from Guy L. Steele. |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/bitops.h> |
| * int_sqrt - computes the integer square root |
| * @x: integer of which to calculate the sqrt |
| * Computes: floor(sqrt(x)) |
| unsigned long int_sqrt(unsigned long x) |
| unsigned long b, m, y = 0; |
| m = 1UL << (__fls(x) & ~1UL); |
| * int_sqrt64 - strongly typed int_sqrt function when minimum 64 bit input |
| * @x: 64bit integer of which to calculate the sqrt |
| return int_sqrt((unsigned long) x); |
| m = 1ULL << (fls64(x) & ~1ULL); |
| EXPORT_SYMBOL(int_sqrt64); |