pnBitfield :: Slice Int -> PNExpr -> PNExpr
    pnBitfield slice expr
        | isEmptySlice slice = PNLiteral NoSimValue
        | otherwise = PNBitfield slice expr
pnBitfield :: Slice Int -> PNExpr -> PNExpr
pnBitfield slice expr
        | isEmptySlice slice = PNLiteral NoSimValue
        | otherwise = PNBitfield slice expr
pnBitfield slice expr
        | isEmptySlice slice = PNLiteral NoSimValue
        | otherwise = PNBitfield slice expr