blob: 464152410c5123e191324a4cfb3ca5ea8ff66687
1 | #include <linux/kernel.h> |
2 | #include <asm/div64.h> |
3 | #include <linux/reciprocal_div.h> |
4 | #include <linux/export.h> |
5 | |
6 | /* |
7 | * For a description of the algorithm please have a look at |
8 | * include/linux/reciprocal_div.h |
9 | */ |
10 | |
11 | struct reciprocal_value reciprocal_value(u32 d) |
12 | { |
13 | struct reciprocal_value R; |
14 | u64 m; |
15 | int l; |
16 | |
17 | l = fls(d - 1); |
18 | m = ((1ULL << 32) * ((1ULL << l) - d)); |
19 | do_div(m, d); |
20 | ++m; |
21 | R.m = (u32)m; |
22 | R.sh1 = min(l, 1); |
23 | R.sh2 = max(l - 1, 0); |
24 | |
25 | return R; |
26 | } |
27 | EXPORT_SYMBOL(reciprocal_value); |
28 |