Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
809fa972 | 2 | #include <linux/kernel.h> |
6a2d7a95 ED |
3 | #include <asm/div64.h> |
4 | #include <linux/reciprocal_div.h> | |
8af2a218 | 5 | #include <linux/export.h> |
6a2d7a95 | 6 | |
809fa972 HFS |
7 | /* |
8 | * For a description of the algorithm please have a look at | |
9 | * include/linux/reciprocal_div.h | |
10 | */ | |
11 | ||
12 | struct reciprocal_value reciprocal_value(u32 d) | |
6a2d7a95 | 13 | { |
809fa972 HFS |
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; | |
6a2d7a95 | 27 | } |
8af2a218 | 28 | EXPORT_SYMBOL(reciprocal_value); |