IndexCPU2.hs

[..]

data CPUState waitCycles
  = Idle
  | Waiting (Index waitCycles)
  deriving (Generic, NFData, Show)

[..]

cpu
  :: forall waitCycles
   . (CPUState, Int)
  -- ^ State
  -> Maybe (Instruction waitCycles)
  -- ^ Input
  -> ((CPUState, Int), (Maybe Int, Ready))
  -- (New state, output)
  
--  state          input          new state                   output
cpu (Idle, _)      Nothing      = ((Idle, 0),                  (Nothing, Ready))
cpu (Idle, _)      (Just instr) = ((Waiting 0, doInstr instr), (Nothing, Busy))
cpu (Waiting 0, r) _            = ((Idle, 0),                  (Just r, Ready))
cpu (Waiting n, r) _            = ((Waiting (pred n), r),      (Nothing, Busy))

[..]

cpuWaiting5Cycles = cpu @5 (Idle, 0)