From ddb15cea4a02c403160c2d9772f85c122cbc8248 Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Fri, 17 Feb 2017 11:32:08 -0800 Subject: math/bits: much faster ReverseBytes, added respective benchmarks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Measured on 2.3 GHz Intel Core i7, running maxOS 10.12.3. benchmark old ns/op new ns/op delta BenchmarkReverseBytes-8 11.4 3.51 -69.21% BenchmarkReverseBytes16-8 6.87 0.64 -90.68% BenchmarkReverseBytes32-8 7.79 0.65 -91.66% BenchmarkReverseBytes64-8 11.6 0.64 -94.48% name old time/op new time/op delta ReverseBytes-8 11.4ns ± 0% 3.5ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes16-8 6.87ns ± 0% 0.64ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes32-8 7.79ns ± 0% 0.65ns ± 0% ~ (p=1.000 n=1+1) ReverseBytes64-8 11.6ns ± 0% 0.6ns ± 0% ~ (p=1.000 n=1+1) Change-Id: I67b529652b3b613c61687e9e185e8d4ee40c51a2 Reviewed-on: https://go-review.googlesource.com/37211 Run-TryBot: Robert Griesemer Reviewed-by: Matthew Dempsky --- src/math/bits/bits_impl.go | 8 -------- 1 file changed, 8 deletions(-) (limited to 'src/math/bits/bits_impl.go') diff --git a/src/math/bits/bits_impl.go b/src/math/bits/bits_impl.go index da38429fee..3a425e3b83 100644 --- a/src/math/bits/bits_impl.go +++ b/src/math/bits/bits_impl.go @@ -93,14 +93,6 @@ func rot(x uint64, size, k uint) uint64 { return x<>(size-k)&(1< 0; i-- { - r = r<<8 | x&0xff - x >>= 8 - } - return -} - func blen(x uint64) (i int) { for ; x >= 1<<(16-1); x >>= 16 { i += 16 -- cgit v1.3-5-g9baa