Sample vs simulate behaviour

[ra1u]

Is this bahaviour expected (notice difference between test1 and test2 output )?

Can I use sample to behave as simulate and that output does not start with 2 zeros?

import Clash.Prelude
import qualified Prelude as P

test1 = P.take 10 $ sample
                   $ register @System (0 :: (Signed 5))
                   $ fromList
                   $ P.repeat 1
-- test1 == [0,0,1,1,1,1,1,1,1,1]

test2 = P.take 10 $ simulate
                  ( register @System (0 :: (Signed 5)))
                  $ P.repeat 1
-- test2 == [0,1,1,1,1,1,1,1,1,1]

My version is 1.4.2.

[martijnbastiaan]

Is this bahaviour expected (notice difference between test1 and test2 output )?

Yes, insofar as that the documentation of sample says:

If the given component has not yet been given a clock, reset, or enable line, sample will supply them. The reset will be asserted for a single cycle. sample will not drop the value produced by the circuit while the reset was asserted. If you want this, or if you want more than a single cycle reset, consider using sampleWithReset.

Documentation of simulate:

Where 'System' denotes the /domain/ to simulate on. The reset line is asserted for a single cycle. The first value is therefore supplied twice to the circuit: once while reset is high, and once directly after. The first /output/ value (the value produced while the reset is asserted) is dropped.

(It does look like the Haddock is missing this simulate documentation for some reason.)

Is this bahaviour expected (notice difference between test1 and test2 output )?

No, insofar as that you didn't expect it, and I think it's a bit of a wart to have them behave differently.

Can I use sample to behave as simulate and that output does not start with 2 zeros?

Yes, use sampleWithReset.