• Robert Griesemer's avatar
    math/bits: faster OnesCount · 177dfba1
    Robert Griesemer authored
    Using some additional suggestions per "Hacker's Delight".
    Added documentation and extra tests.
    
    Measured on 1.7 GHz Intel Core i7, running macOS 10.12.3.
    
    benchmark                  old ns/op     new ns/op     delta
    BenchmarkOnesCount-4       7.34          5.38          -26.70%
    BenchmarkOnesCount8-4      2.03          1.98          -2.46%
    BenchmarkOnesCount16-4     2.56          2.50          -2.34%
    BenchmarkOnesCount32-4     2.98          2.39          -19.80%
    BenchmarkOnesCount64-4     4.22          2.96          -29.86%
    
    Change-Id: I566b0ef766e55cf5776b1662b6016024ebe5d878
    Reviewed-on: https://go-review.googlesource.com/37223Reviewed-by: 's avatarMatthew Dempsky <mdempsky@google.com>
    Run-TryBot: Matthew Dempsky <mdempsky@google.com>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    177dfba1
bits_test.go 16.6 KB