Copyright	(c) Edward Kmett 2013-2014
License	BSD3
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	experimental
Portability	non-portable
Safe Haskell	Trustworthy
Language	Haskell2010

Data.Bits.Extras

Description

Calculate a number of fiddly bit operations using fast de Bruijn multiplication tables.

Synopsis

class (Num t, FiniteBits t) => Ranked t where
- lsb :: t -> Int
- rank :: t -> Int
- nlz :: t -> Int
log2 :: Word32 -> Int
msb :: Ranked t => t -> Int
w8 :: Integral a => a -> Word8
w16 :: Integral a => a -> Word16
w32 :: Integral a => a -> Word32
w64 :: Integral a => a -> Word64
assignBit :: Bits b => b -> Int -> Bool -> b
zeroBits :: Bits a => a
oneBits :: Bits b => b
srl :: Bits b => b -> Int -> b

Documentation

class (Num t, FiniteBits t) => Ranked t where Source #

Minimal complete definition

Methods

Calculate the least significant set bit using a debruijn multiplication table. NB: The result of this function is undefined when given 0.

Calculate the number of trailing 0 bits.

Calculate the number of leading zeros.

Instances details

Ranked Int8 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Int8 -> Int Source # rank :: Int8 -> Int Source # nlz :: Int8 -> Int Source #
Ranked Int16 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Int16 -> Int Source # rank :: Int16 -> Int Source # nlz :: Int16 -> Int Source #
Ranked Int32 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Int32 -> Int Source # rank :: Int32 -> Int Source # nlz :: Int32 -> Int Source #
Ranked Int64 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Int64 -> Int Source # rank :: Int64 -> Int Source # nlz :: Int64 -> Int Source #
Ranked Word8 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Word8 -> Int Source # rank :: Word8 -> Int Source # nlz :: Word8 -> Int Source #
Ranked Word16 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Word16 -> Int Source # rank :: Word16 -> Int Source # nlz :: Word16 -> Int Source #
Ranked Word32 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Word32 -> Int Source # rank :: Word32 -> Int Source # nlz :: Word32 -> Int Source #
Ranked Word64 Source #
Instance details Defined in Data.Bits.Extras Methods lsb :: Word64 -> Int Source # rank :: Word64 -> Int Source # nlz :: Word64 -> Int Source #

Calculate the most significant set bit.

zeroBits is the value with all bits unset.

The following laws ought to hold (for all valid bit indices n):

This method uses clearBit (bit 0) 0 as its default implementation (which ought to be equivalent to zeroBits for types which possess a 0th bit).

Since: base-4.7.0.0

srl :: Bits b => b -> Int -> b Source #

Shift Right Logical (i.e., without sign extension)

NB: When used on negative Integers, hilarity may ensue.