Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <asm/div64.h>
4#include <linux/reciprocal_div.h>
5#include <linux/export.h>
6
7/*
8 * For a description of the algorithm please have a look at
9 * include/linux/reciprocal_div.h
10 */
11
12struct reciprocal_value reciprocal_value(u32 d)
13{
14 struct reciprocal_value R;
15 u64 m;
16 int l;
17
18 l = fls(d - 1);
19 m = ((1ULL << 32) * ((1ULL << l) - d));
20 do_div(m, d);
21 ++m;
22 R.m = (u32)m;
23 R.sh1 = min(l, 1);
24 R.sh2 = max(l - 1, 0);
25
26 return R;
27}
28EXPORT_SYMBOL(reciprocal_value);