diff options
| author | Ingo Molnar <mingo@kernel.org> | 2014-02-02 09:45:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-02-02 09:45:39 +0100 |
| commit | eaa4e4fcf1b5c60e656d93242f7fe422173f25b2 (patch) | |
| tree | c05d5d6ca3f625d72a9d136b4c485d3dc9472089 /lib/reciprocal_div.c | |
| parent | be1e4e760d940c14d119bffef5eb007dfdf29046 (diff) | |
| parent | 5cb480f6b488128140c940abff3c36f524a334a8 (diff) | |
Merge branch 'linus' into sched/core, to resolve conflicts
Conflicts:
kernel/sysctl.c
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'lib/reciprocal_div.c')
| -rw-r--r-- | lib/reciprocal_div.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/lib/reciprocal_div.c b/lib/reciprocal_div.c index 75510e94f7d0..464152410c51 100644 --- a/lib/reciprocal_div.c +++ b/lib/reciprocal_div.c @@ -1,11 +1,27 @@ +#include <linux/kernel.h> #include <asm/div64.h> #include <linux/reciprocal_div.h> #include <linux/export.h> -u32 reciprocal_value(u32 k) +/* + * For a description of the algorithm please have a look at + * include/linux/reciprocal_div.h + */ + +struct reciprocal_value reciprocal_value(u32 d) { - u64 val = (1LL << 32) + (k - 1); - do_div(val, k); - return (u32)val; + struct reciprocal_value R; + u64 m; + int l; + + l = fls(d - 1); + m = ((1ULL << 32) * ((1ULL << l) - d)); + do_div(m, d); + ++m; + R.m = (u32)m; + R.sh1 = min(l, 1); + R.sh2 = max(l - 1, 0); + + return R; } EXPORT_SYMBOL(reciprocal_value); |
