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| author | Robert Griesemer <gri@golang.org> | 2017-02-17 15:02:49 -0800 |
|---|---|---|
| committer | Robert Griesemer <gri@golang.org> | 2017-02-17 23:40:45 +0000 |
| commit | 19028bdd18483689a3743639fa89d272cbb96c7b (patch) | |
| tree | 57878271b3cef4b4e0f24206ab3575f1c429dd39 /src/math/bits/bits_impl.go | |
| parent | a12edb8db6f3fa93a1ccd96a0f84b647d08429ef (diff) | |
| download | go-19028bdd18483689a3743639fa89d272cbb96c7b.tar.xz | |
math/bits: faster Rotate functions, added respective benchmarks
Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3.
benchmark old ns/op new ns/op delta
BenchmarkRotateLeft-8 7.87 7.00 -11.05%
BenchmarkRotateLeft8-8 8.41 4.52 -46.25%
BenchmarkRotateLeft16-8 8.07 4.55 -43.62%
BenchmarkRotateLeft32-8 8.36 4.73 -43.42%
BenchmarkRotateLeft64-8 7.93 4.78 -39.72%
BenchmarkRotateRight-8 8.23 6.72 -18.35%
BenchmarkRotateRight8-8 8.76 4.39 -49.89%
BenchmarkRotateRight16-8 9.07 4.44 -51.05%
BenchmarkRotateRight32-8 8.85 4.46 -49.60%
BenchmarkRotateRight64-8 8.11 4.43 -45.38%
Change-Id: I79ea1e9e6fc65f95794a91f860a911efed3aa8a1
Reviewed-on: https://go-review.googlesource.com/37219
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Diffstat (limited to 'src/math/bits/bits_impl.go')
| -rw-r--r-- | src/math/bits/bits_impl.go | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/src/math/bits/bits_impl.go b/src/math/bits/bits_impl.go index c7834106c8..e7c1a8a5dc 100644 --- a/src/math/bits/bits_impl.go +++ b/src/math/bits/bits_impl.go @@ -74,17 +74,6 @@ func ntz64(x uint64) int { return int(deBruijn64tab[(x&-x)*deBruijn64>>(64-6)]) } -func pos(k int) uint { - if k < 0 { - panic("negative rotation count") - } - return uint(k) -} - -func rot(x uint64, size, k uint) uint64 { - return x<<k | x>>(size-k)&(1<<k-1) -} - func blen(x uint64) (i int) { for ; x >= 1<<(16-1); x >>= 16 { i += 16 |