AutoReg - Uses beyond Maybe

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1

I’ve got two AutoReg questions:

Is there a reason there’s no instance for RamOp, other than no one’s written it? (I have now…*)

And it seems beneficial for there to be a version of mealy which uses AutoReg internally, is there a good reason that doesn’t exist, other than no one’s written it? (and the explosion of mealy functions after mealyB, mealyS and mealySB…).

Am I missing anything obvious?

*Implementation below:

instance (AutoReg a, KnownNat n) => AutoReg (RamOp n a) where
  autoReg clk rst en initVal input =
    createRamOp <$> tagR <*> valAddr <*> valValue
    where
      tag = toTag <$> input

      toTag = \case
                RamNoOp    -> 0b00 :: BitVector 2
                RamRead{}  -> 0b01
                RamWrite{} -> 0b10

      tagInit = toTag initVal
      tagR = register clk rst en tagInit tag

      toAddr  = \case
                RamNoOp         -> deepErrorX "autoReg'.ramOpAddr"
                RamRead addr    -> addr
                RamWrite addr _ -> addr

      toValue  = \case
                RamWrite _ a -> a
                _ -> deepErrorX "autoReg'.ramOpValue"


      ramOpAddr  = toAddr <$> input
      ramOpValue = toValue <$> input

      addrInit = toAddr   initVal
      valInit  = toValue initVal

      valAddr  = autoReg clk rst (andEnable en ((/=0) <$> tag)) addrInit ramOpAddr
      valValue = autoReg clk rst (andEnable en (bitToBool . msb <$> tag)) valInit ramOpValue

      createRamOp t addr val = case t of
        0 -> RamNoOp
        1 -> RamRead addr
        2 -> RamWrite addr val
        _ -> deepErrorX  "autoReg'.createRamOp: impossible"

  {-# INLINE autoReg #-}
2

Personally I’ve never use AutoReg (maybe I should :eyes:) and I can’t easily verify if your instance is correct. However, I did write RamOp and don’t see any reason why it should not have an AutoReg instance :slight_smile: