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| author | Andreas Rumpf <andreasrumpf@noname> | 2009-09-15 23:22:22 +0200 |
|---|---|---|
| committer | Andreas Rumpf <andreasrumpf@noname> | 2009-09-15 23:22:22 +0200 |
| commit | 66a7e3d37c0303997a6b1a3b7ec263dfb8c07748 (patch) | |
| tree | 40ae1ab8aeb9086b7310ea73ab8a2ed6b597f88b /lib/pure/math.nim | |
| parent | 300430fbba28b408f7ac86ca46b03d9d50839399 (diff) | |
| download | Nim-66a7e3d37c0303997a6b1a3b7ec263dfb8c07748.tar.gz | |
added tools and web dirs
Diffstat (limited to 'lib/pure/math.nim')
| -rwxr-xr-x[-rw-r--r--] | lib/pure/math.nim | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/lib/pure/math.nim b/lib/pure/math.nim index a3e57e403..bca45894c 100644..100755 --- a/lib/pure/math.nim +++ b/lib/pure/math.nim @@ -1,7 +1,7 @@ # # # Nimrod's Runtime Library -# (c) Copyright 2008 Andreas Rumpf +# (c) Copyright 2009 Andreas Rumpf # # See the file "copying.txt", included in this # distribution, for details about the copyright. @@ -83,10 +83,12 @@ proc nextPowerOfTwo*(x: int): int = result = result or (result shr 1) Inc(result) -proc countBits*(n: int32): int {.noSideEffect.} +proc countBits32*(n: int32): int {.noSideEffect.} = ## counts the set bits in `n`. - -include "system/cntbits" + var v = n + v = v -% ((v shr 1'i32) and 0x55555555'i32) + v = (v and 0x33333333'i32) +% ((v shr 2'i32) and 0x33333333'i32) + result = ((v +% (v shr 4'i32) and 0xF0F0F0F'i32) *% 0x1010101'i32) shr 24'i32 proc sum*[T](x: openarray[T]): T {.noSideEffect.} = ## computes the sum of the elements in `x`. |