Clash.Signal.Delayed

Delay-annotated synchronous signals

data DSignal (dom :: Domain) (delay :: Nat) a

A synchronized signal with samples of type a, synchronized to clock clk, that has accumulated delay amount of samples delay along its path.

DSignal has the type role

>>> :i DSignal
type role DSignal nominal nominal representational
...

as it is safe to coerce the values in the signal, but not safe to coerce the synthesis domain or delay in the signal.

Instances

Lift a => Lift (DSignal dom delay a :: Type)

Defined in Clash.Signal.Delayed.Internal

Methods

lift :: DSignal dom delay a -> Q Exp

liftTyped :: DSignal dom delay a -> Q (TExp (DSignal dom delay a))

Functor (DSignal dom delay)

Defined in Clash.Signal.Delayed.Internal

Methods

fmap :: (a -> b) -> DSignal dom delay a -> DSignal dom delay b

(<$) :: a -> DSignal dom delay b -> DSignal dom delay a

Applicative (DSignal dom delay)

Defined in Clash.Signal.Delayed.Internal

Methods

pure :: a -> DSignal dom delay a

(<*>) :: DSignal dom delay (a -> b) -> DSignal dom delay a -> DSignal dom delay b

liftA2 :: (a -> b -> c) -> DSignal dom delay a -> DSignal dom delay b -> DSignal dom delay c

(*>) :: DSignal dom delay a -> DSignal dom delay b -> DSignal dom delay b

(<*) :: DSignal dom delay a -> DSignal dom delay b -> DSignal dom delay a

Foldable (DSignal dom delay)

Defined in Clash.Signal.Delayed.Internal

Methods

fold :: Monoid m => DSignal dom delay m -> m

foldMap :: Monoid m => (a -> m) -> DSignal dom delay a -> m

foldMap' :: Monoid m => (a -> m) -> DSignal dom delay a -> m

foldr :: (a -> b -> b) -> b -> DSignal dom delay a -> b

foldr' :: (a -> b -> b) -> b -> DSignal dom delay a -> b

foldl :: (b -> a -> b) -> b -> DSignal dom delay a -> b

foldl' :: (b -> a -> b) -> b -> DSignal dom delay a -> b

foldr1 :: (a -> a -> a) -> DSignal dom delay a -> a

foldl1 :: (a -> a -> a) -> DSignal dom delay a -> a

toList :: DSignal dom delay a -> [a]

null :: DSignal dom delay a -> Bool

length :: DSignal dom delay a -> Int

elem :: Eq a => a -> DSignal dom delay a -> Bool

maximum :: Ord a => DSignal dom delay a -> a

minimum :: Ord a => DSignal dom delay a -> a

sum :: Num a => DSignal dom delay a -> a

product :: Num a => DSignal dom delay a -> a

Traversable (DSignal dom delay)

Defined in Clash.Signal.Delayed.Internal

Methods

traverse :: Applicative f => (a -> f b) -> DSignal dom delay a -> f (DSignal dom delay b)

sequenceA :: Applicative f => DSignal dom delay (f a) -> f (DSignal dom delay a)

mapM :: Monad m => (a -> m b) -> DSignal dom delay a -> m (DSignal dom delay b)

sequence :: Monad m => DSignal dom delay (m a) -> m (DSignal dom delay a)

Fractional a => Fractional (DSignal dom delay a)

Defined in Clash.Signal.Delayed.Internal

Methods

(/) :: DSignal dom delay a -> DSignal dom delay a -> DSignal dom delay a

recip :: DSignal dom delay a -> DSignal dom delay a

fromRational :: Rational -> DSignal dom delay a

Num a => Num (DSignal dom delay a)

Defined in Clash.Signal.Delayed.Internal

Methods

(+) :: DSignal dom delay a -> DSignal dom delay a -> DSignal dom delay a

(-) :: DSignal dom delay a -> DSignal dom delay a -> DSignal dom delay a

(*) :: DSignal dom delay a -> DSignal dom delay a -> DSignal dom delay a

negate :: DSignal dom delay a -> DSignal dom delay a

abs :: DSignal dom delay a -> DSignal dom delay a

signum :: DSignal dom delay a -> DSignal dom delay a

fromInteger :: Integer -> DSignal dom delay a

Show a => Show (DSignal dom delay a)

Defined in Clash.Signal.Delayed.Internal

Methods

showsPrec :: Int -> DSignal dom delay a -> ShowS

show :: DSignal dom delay a -> String

showList :: [DSignal dom delay a] -> ShowS

Arbitrary a => Arbitrary (DSignal dom delay a)

Defined in Clash.Signal.Delayed.Internal

Methods

arbitrary :: Gen (DSignal dom delay a)

shrink :: DSignal dom delay a -> [DSignal dom delay a]

CoArbitrary a => CoArbitrary (DSignal dom delay a)

Defined in Clash.Signal.Delayed.Internal

Methods

coarbitrary :: DSignal dom delay a -> Gen b -> Gen b

Default a => Default (DSignal dom delay a)

Defined in Clash.Signal.Delayed.Internal

Methods

def :: DSignal dom delay a

type HasDomain dom1 (DSignal dom2 delay a)

Defined in Clash.Class.HasDomain.HasSpecificDomain

type HasDomain dom1 (DSignal dom2 delay a) = DomEq dom1 dom2

type TryDomain t (DSignal dom delay a)

Defined in Clash.Class.HasDomain.HasSingleDomain

type TryDomain t (DSignal dom delay a) = 'Found dom

delayed :: (KnownNat d, HiddenClockResetEnable dom, NFDataX a) => Vec d a -> DSignal dom n a -> DSignal dom (n + d) a

Delay a DSignal for d periods.

delay3
  :: HiddenClockResetEnable dom
  => DSignal dom n Int
  -> DSignal dom (n + 3) Int
delay3 = delayed (-1 :> -1 :> -1 :> Nil)

>>> sampleN @System 7 (toSignal (delay3 (dfromList [0..])))
[-1,-1,-1,-1,1,2,3]

delayedI

Arguments

:: (KnownNat d, NFDataX a, HiddenClockResetEnable dom)

=> a

Initial value

-> DSignal dom n a

-> DSignal dom (n + d) a

Delay a DSignal for d periods, where d is derived from the context.

delay2
  :: HiddenClockResetEnable dom
  => Int
  -> DSignal dom n Int
  -> DSignal dom (n + 2) Int
delay2 = delayedI

>>> sampleN @System 7 (toSignal (delay2 (-1) (dfromList [0..])))
[-1,-1,-1,1,2,3,4]

Or d can be specified using type application:

>>> :t delayedI @3
delayedI @3
  :: (...
      ...
      ...
      ...) =>
     a -> DSignal dom n a -> DSignal dom (n + 3) a

delayN

Arguments

:: forall dom a d n. (HiddenClock dom, HiddenEnable dom, NFDataX a)

=> SNat d

-> a

Initial value

-> DSignal dom n a

-> DSignal dom (n + d) a

Delay a DSignal for d cycles, the value at time 0..d-1 is a.

delayN2
  :: ( HiddenClock dom
     , HiddenEnable dom )
  => Int
  -> DSignal dom n Int
  -> DSignal dom (n + 2) Int
delayN2 = delayN d2

>>> printX $ sampleN @System 6 (toSignal (delayN2 (-1) (dfromList [1..])))
[-1,-1,1,2,3,4]

delayI

Arguments

:: forall d n a dom. (HiddenClock dom, HiddenEnable dom, NFDataX a, KnownNat d)

=> a

Initial value

-> DSignal dom n a

-> DSignal dom (n + d) a

Delay a DSignal for d cycles, where d is derived from the context. The value at time 0..d-1 is a default value.

delayI2
  :: ( HiddenClock dom
     , HiddenEnable dom )
  => Int
  -> DSignal dom n Int
  -> DSignal dom (n + 2) Int
delayI2 = delayI

>>> sampleN @System 6 (toSignal (delayI2 (-1) (dfromList [1..])))
[-1,-1,1,2,3,4]

You can also use type application to do the same:

>>> sampleN @System 6 (toSignal (delayI @2 (-1) (dfromList [1..])))
[-1,-1,1,2,3,4]

delayedFold

Arguments

:: forall dom n delay k a. (HiddenClock dom, HiddenEnable dom, NFDataX a, KnownNat delay, KnownNat k)

=> SNat delay

Delay applied after each step

-> a

Initial value

-> (a -> a -> a)

Fold operation to apply

-> Vec (2 ^ k) (DSignal dom n a)

Vector input of size 2^k

-> DSignal dom (n + (delay * k)) a

Output Signal delayed by (delay * k)

Tree fold over a Vec of DSignals with a combinatorial function, and delaying delay cycles after each application. Values at times 0..(delay*k)-1 are set to a default.

countingSignals :: Vec 4 (DSignal dom 0 Int)
countingSignals = repeat (dfromList [0..])

>>> printX $ sampleN @System 6 (toSignal (delayedFold d1 (-1) (+) countingSignals))
[-1,-2,0,4,8,12]

>>> printX $ sampleN @System 8 (toSignal (delayedFold d2 (-1) (*) countingSignals))
[-1,-1,1,1,0,1,16,81]

feedback :: (DSignal dom n a -> (DSignal dom n a, DSignal dom ((n + m) + 1) a)) -> DSignal dom n a

Feed the delayed result of a function back to its input:

mac
  :: forall dom
   . KnownDomain dom
  => Clock dom
  -> Reset dom
  -> Enable dom
  -> DSignal dom 0 Int
  -> DSignal dom 0 Int
  -> DSignal dom 0 Int
mac clk rst en x y = feedback (mac' x y)
  where
    mac'
      :: DSignal dom 0 Int
      -> DSignal dom 0 Int
      -> DSignal dom 0 Int
      -> (DSignal dom 0 Int, DSignal dom 1 Int)
    mac' a b acc = let acc' = a * b + acc
                   in  (acc, delayedI clk rst en 0 acc')

>>> sampleN 7 (toSignal (mac systemClockGen systemResetGen enableGen (dfromList [0..]) (dfromList [0..])))
[0,0,1,5,14,30,55]

Signal <-> DSignal conversion

fromSignal :: Signal dom a -> DSignal dom 0 a

Signals are not delayed

toSignal :: DSignal dom delay a -> Signal dom a

Strip a DSignal of its delay information.

List <-> DSignal conversion (not synthesizable)

dfromList :: NFDataX a => [a] -> DSignal dom 0 a

Create a DSignal from a list

Every element in the list will correspond to a value of the signal for one clock cycle.

>>> sampleN 2 (toSignal (dfromList [1,2,3,4,5]))
[1,2]

NB: This function is not synthesizable

lazy versions

dfromList_lazy :: [a] -> DSignal dom 0 a

Create a DSignal from a list

Every element in the list will correspond to a value of the signal for one clock cycle.

>>> sampleN 2 (toSignal (dfromList [1,2,3,4,5]))
[1,2]

NB: This function is not synthesizable

Experimental

unsafeFromSignal :: Signal dom a -> DSignal dom n a

EXPERIMENTAL

Unsafely convert a Signal to a DSignal with an arbitrary delay.

NB: Should only be used to interface with functions specified in terms of Signal.

antiDelay :: SNat d -> DSignal dom (n + d) a -> DSignal dom n a

EXPERIMENTAL

Access a delayed signal from the future in the present. Often required When writing a circuit that requires feedback from itself.

mac
  :: KnownDomain dom
  => Clock dom
  -> Reset dom
  -> Enable dom
  -> DSignal dom 0 Int
  -> DSignal dom 0 Int
  -> DSignal dom 0 Int
mac clk rst en x y = acc'
  where
    acc' = (x * y) + antiDelay d1 acc
    acc  = delayedI clk rst en 0 acc'

forward :: SNat d -> DSignal dom n a -> DSignal dom (n + d) a

EXPERIMENTAL

Access a delayed signal from the past in the present. In contrast with delayed and friends forward does not insert any logic. This means using this function violates the delay invariant of DSignal. This is sometimes useful when combining unrelated delayed signals where inserting logic is not wanted or when abstracting over internal delayed signals where the internal delay information should not be leaked.

For example, the circuit below returns a sequence of numbers as a pair but the internal delay information between the elements of the pair should not leak into the type.

numbers
  :: forall dom
   . KnownDomain dom
  => Clock dom
  -> Reset dom
  -> Enable dom
  -> DSignal dom 5 (Int, Int)
numbers clk rst en = DB.bundle (forward d1 s1, s2)
  where
    s1 :: DSignal dom 4 Int
    s1 = delayed clk rst en (100 :> 10 :> 5 :> 1 :> Nil) (pure 200)
    s2 :: DSignal dom 5 Int
    s2 = fmap (2*) $ delayN d1 0 en clk s1

>>> sampleN 8 (toSignal (numbers systemClockGen systemResetGen enableGen))
[(1,0),(1,2),(5,2),(10,10),(100,20),(200,200),(200,400),(200,400)]