edsl.hs

-- Fixed point registers
data Rx = R0 | R1 | R2 | R3 | R4 | R5 | R6 | R7 deriving (Show, Eq, Ord) 
-- Floating point registers
data Fx = F0 | F1 | F2 | F3 | F4 | F5 | F6 | F7 deriving (Show, Eq, Ord)

data Expr :: * -> * where
  AddI  :: Rx -> Rx -> Expr Integer
  SubI  :: Rx -> Rx -> Expr Integer
  AddF  :: Fx -> Fx -> Expr Float
  SubF  :: Fx -> Fx -> Expr Float

class ALU a b | a -> b where
  add  :: a -> a -> b
  sub  :: a -> a -> b

instance ALU Rx (Expr Integer) where
  add m n  = AddI m n
  sub m n  = SubI m n

instance ALU Fx (Expr Float) where
  add m n  = AddF m n
  sub m n  = SubF m n