Clash.Prelude.Moore

Whereas the output of a Mealy machine depends on current transition, the output of a Moore machine depends on the previous state.

Moore machines are strictly less expressive, but may impose laxer timing requirements.

Moore machine

moore

Arguments

:: HiddenClockReset domain gated synchronous

=> (s -> i -> s)

Transfer function in moore machine form: state -> input -> newstate

-> (s -> o)

Output function in moore machine form: state -> output

-> s

Initial state

-> Signal domain i -> Signal domain o

Synchronous sequential function with input and output matching that of the moore machine

Create a synchronous function from a combinational function describing a moore machine

macT :: Int        -- Current state
     -> (Int,Int)  -- Input
     -> Int        -- Updated state
macT s (x,y) = x * y + s

mac :: HiddenClockReset domain gated synchronous => Signal domain (Int, Int) -> Signal domain Int
mac = moore mac id 0

>>> simulate mac [(1,1),(2,2),(3,3),(4,4)]
[0,1,5,14...
...

Synchronous sequential functions can be composed just like their combinational counterpart:

dualMac
  :: HiddenClockReset domain gated synchronous
  => (Signal domain Int, Signal domain Int)
  -> (Signal domain Int, Signal domain Int)
  -> Signal domain Int
dualMac (a,b) (x,y) = s1 + s2
  where
    s1 = moore mac id 0 (bundle (a,x))
    s2 = moore mac id 0 (bundle (b,y))

mooreB

Arguments

:: (Bundle i, Bundle o, HiddenClockReset domain gated synchronous)

=> (s -> i -> s)

Transfer function in moore machine form: state -> input -> newstate

-> (s -> o)

Output function in moore machine form: state -> output

-> s

Initial state

-> Unbundled domain i -> Unbundled domain o

Synchronous sequential function with input and output matching that of the moore machine

A version of moore that does automatic Bundleing

Given a functions t and o of types:

t :: Int -> (Bool, Int) -> Int
o :: Int -> (Int, Bool)

When we want to make compositions of t and o in g using moore, we have to write:

g a b c = (b1,b2,i2)
  where
    (i1,b1) = unbundle (moore t o 0 (bundle (a,b)))
    (i2,b2) = unbundle (moore t o 3 (bundle (i1,c)))

Using mooreB however we can write:

g a b c = (b1,b2,i2)
  where
    (i1,b1) = mooreB t o 0 (a,b)
    (i2,b2) = mooreB t o 3 (i1,c)

medvedev :: HiddenClockReset domain gated synchronous => (s -> i -> s) -> s -> Signal domain i -> Signal domain s

Create a synchronous function from a combinational function describing a moore machine without any output logic

medvedevB :: (Bundle i, Bundle s, HiddenClockReset domain gated synchronous) => (s -> i -> s) -> s -> Unbundled domain i -> Unbundled domain s

A version of medvedev that does automatic Bundleing