{-|
Copyright  :  (C) 2013-2016, University of Twente
                  2022-2024, Google Inc.
License    :  BSD2 (see the file LICENSE)
Maintainer :  Christiaan Baaij <christiaan.baaij@gmail.com>
-}

{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE TypeFamilies #-}

{-# OPTIONS_HADDOCK show-extensions #-}

module Clash.Sized.BitVector
  ( -- * Bit
    Bit
    -- ** Construction
    -- *** Initialisation
  , high
  , low
    -- * BitVector
  , BitVector
    -- ** Accessors
    -- *** Length information
  , size#
  , maxIndex#
    -- ** Construction
  , bLit
  , hLit
  , oLit
    -- ** Concatenation
  , (++#)
    -- * Modification
  , (+>>.)
  , (.<<+)
    -- ** Pattern matching
  , bitPattern
  )
where

import Clash.Sized.Internal.BitVector
import Clash.Promoted.Nat (SNat(..), SNatLE(..), compareSNat, natToNum)
import Data.Bits (shiftL, shiftR)
import GHC.TypeNats (KnownNat)

{- $setup
>>> :set -XNumericUnderscores
-}

infixr 4 +>>.
-- | Shift in a bit from the MSB side of a 'BitVector'. Equal to right shifting
-- the 'BitVector' by one and replacing the MSB with the bit to be shifted in.
--
-- >>> 1 +>>. 0b1111_0000 :: BitVector 8
-- 0b1111_1000
-- >>> 0 +>>. 0b1111_0000 :: BitVector 8
-- 0b0111_1000
--
(+>>.) :: forall n. KnownNat n => Bit -> BitVector n -> BitVector n
Bit
b +>>. :: Bit -> BitVector n -> BitVector n
+>>. BitVector n
bv = case SNat n -> SNat 0 -> SNatLE n 0
forall (a :: Nat) (b :: Nat). SNat a -> SNat b -> SNatLE a b
compareSNat (KnownNat n => SNat n
forall (n :: Nat). KnownNat n => SNat n
SNat @n) (KnownNat 0 => SNat 0
forall (n :: Nat). KnownNat n => SNat n
SNat @0) of
  SNatLE n 0
SNatGT -> BitVector n -> Int -> Bit -> BitVector n
forall (n :: Nat).
KnownNat n =>
BitVector n -> Int -> Bit -> BitVector n
replaceBit# (BitVector n -> Int -> BitVector n
forall a. Bits a => a -> Int -> a
shiftR BitVector n
bv Int
1) (forall a. (Num a, KnownNat n) => a
forall (n :: Nat) a. (Num a, KnownNat n) => a
natToNum @n Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
1) Bit
b
  SNatLE n 0
SNatLE -> BitVector n
bv

infixr 4 .<<+
-- | Shift in a bit from the LSB side of a 'BitVector'. Equal to left shifting
-- the 'BitVector' by one and replacing the LSB with the bit to be shifted in.
--
-- >>> 0b1111_0000 .<<+ 0 :: BitVector 8
-- 0b1110_0000
-- >>> 0b1111_0000 .<<+ 1 :: BitVector 8
-- 0b1110_0001
--
(.<<+) :: forall n. KnownNat n => BitVector n -> Bit -> BitVector n
BitVector n
bv .<<+ :: BitVector n -> Bit -> BitVector n
.<<+ Bit
b = case SNat n -> SNat 0 -> SNatLE n 0
forall (a :: Nat) (b :: Nat). SNat a -> SNat b -> SNatLE a b
compareSNat (KnownNat n => SNat n
forall (n :: Nat). KnownNat n => SNat n
SNat @n) (KnownNat 0 => SNat 0
forall (n :: Nat). KnownNat n => SNat n
SNat @0) of
  SNatLE n 0
SNatGT -> BitVector n -> Int -> Bit -> BitVector n
forall (n :: Nat).
KnownNat n =>
BitVector n -> Int -> Bit -> BitVector n
replaceBit# (BitVector n -> Int -> BitVector n
forall a. Bits a => a -> Int -> a
shiftL BitVector n
bv Int
1) Int
0 Bit
b
  SNatLE n 0
SNatLE -> BitVector n
bv