module Copilot.Language.Operators.Integral
( div
, mod
, (^)
) where
import Copilot.Core (Typed, typeOf)
import qualified Copilot.Core as Core
import Copilot.Language.Operators.BitWise ((.<<.))
import Copilot.Language.Stream
import qualified Data.Bits as B
import qualified Prelude as P
import Data.List (foldl', replicate)
div :: (Typed a, P.Integral a) => Stream a -> Stream a -> Stream a
(Const 0) `div` _ = Const 0
_ `div` (Const 0) = Core.badUsage "in div: division by zero."
x `div` (Const 1) = x
x `div` y = Op2 (Core.Div typeOf) x y
mod :: (Typed a, P.Integral a) => Stream a -> Stream a -> Stream a
_ `mod` (Const 0) = Core.badUsage "in mod: division by zero."
(Const 0) `mod` _ = (Const 0)
(Const x) `mod` (Const y) = Const (x `P.mod` y)
x `mod` y = Op2 (Core.Mod typeOf) x y
(^) :: (Typed a, Typed b, P.Num a, B.Bits a, P.Integral b)
=> Stream a -> Stream b -> Stream a
(Const 0) ^ (Const 0) = Const 1
(Const 0) ^ x = Op3 (Core.Mux typeOf) (Op2 (Core.Eq typeOf) x 0) (1) (0)
(Const 1) ^ _ = Const 1
(Const x) ^ (Const y) = Const (x P.^ y)
(Const 2) ^ y = (Const 1) .<<. y
x ^ (Const y) = foldl' ((P.*)) (Const 1) (replicate (P.fromIntegral y) x)
_ ^ _ = Core.badUsage "in ^: in x ^ y, either x must be the constant 2, or y must be a constant. (Do not confuse ^ with bitwise XOR (.^.) or with ** for exponentation of floats/doubles.)"