Data.Bits.Extras

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

Documentation

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

Minimal complete definition

nlz

Methods

lsb :: t -> Int

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

rank :: t -> Int

Calculate the number of trailing 0 bits.

nlz :: t -> Int

Calculate the number of leading zeros.

Instances

Ranked Int8

Methods

lsb :: Int8 -> Int

rank :: Int8 -> Int

nlz :: Int8 -> Int

Ranked Int16

Methods

lsb :: Int16 -> Int

rank :: Int16 -> Int

nlz :: Int16 -> Int

Ranked Int32

Methods

lsb :: Int32 -> Int

rank :: Int32 -> Int

nlz :: Int32 -> Int

Ranked Int64

Methods

lsb :: Int64 -> Int

rank :: Int64 -> Int

nlz :: Int64 -> Int

Ranked Word8

Methods

lsb :: Word8 -> Int

rank :: Word8 -> Int

nlz :: Word8 -> Int

Ranked Word16

Methods

lsb :: Word16 -> Int

rank :: Word16 -> Int

nlz :: Word16 -> Int

Ranked Word32

Methods

lsb :: Word32 -> Int

rank :: Word32 -> Int

nlz :: Word32 -> Int

Ranked Word64

Methods

lsb :: Word64 -> Int

rank :: Word64 -> Int

nlz :: Word64 -> Int

log2 :: Word32 -> Int

msb :: Ranked t => t -> Int

Calculate the most significant set bit.

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

zeroBits is the value with all bits unset.

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

• clearBit zeroBits n == zeroBits

• setBit   zeroBits n == bit n

• testBit  zeroBits n == False

• popCount zeroBits   == 0

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: 4.7.0.0

oneBits :: Bits b => b

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

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

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