genericWordMul2Op :: GenericOp
genericWordMul2Op [res_h, res_l] [arg_x, arg_y]
 = do dflags <- getDynFlags
      let t = cmmExprType dflags arg_x
      xlyl <- liftM CmmLocal $ newTemp t
      xlyh <- liftM CmmLocal $ newTemp t
      xhyl <- liftM CmmLocal $ newTemp t
      r    <- liftM CmmLocal $ newTemp t
      -- This generic implementation is very simple and slow. We might
      -- well be able to do better, but for now this at least works.
      let topHalf x = CmmMachOp (MO_U_Shr (wordWidth dflags)) [x, hww]
          toTopHalf x = CmmMachOp (MO_Shl (wordWidth dflags)) [x, hww]
          bottomHalf x = CmmMachOp (MO_And (wordWidth dflags)) [x, hwm]
          add x y = CmmMachOp (MO_Add (wordWidth dflags)) [x, y]
          sum = foldl1 add
          mul x y = CmmMachOp (MO_Mul (wordWidth dflags)) [x, y]
          or x y = CmmMachOp (MO_Or (wordWidth dflags)) [x, y]
          hww = CmmLit (CmmInt (fromIntegral (widthInBits (halfWordWidth dflags)))
                               (wordWidth dflags))
          hwm = CmmLit (CmmInt (halfWordMask dflags) (wordWidth dflags))
      emit $ catAGraphs
             [mkAssign xlyl
                  (mul (bottomHalf arg_x) (bottomHalf arg_y)),
              mkAssign xlyh
                  (mul (bottomHalf arg_x) (topHalf arg_y)),
              mkAssign xhyl
                  (mul (topHalf arg_x) (bottomHalf arg_y)),
              mkAssign r
                  (sum [topHalf    (CmmReg xlyl),
                        bottomHalf (CmmReg xhyl),
                        bottomHalf (CmmReg xlyh)]),
              mkAssign (CmmLocal res_l)
                  (or (bottomHalf (CmmReg xlyl))
                      (toTopHalf (CmmReg r))),
              mkAssign (CmmLocal res_h)
                  (sum [mul (topHalf arg_x) (topHalf arg_y),
                        topHalf (CmmReg xhyl),
                        topHalf (CmmReg xlyh),
                        topHalf (CmmReg r)])]
genericWordMul2Op :: GenericOp
genericWordMul2Op [res_h, res_l] [arg_x, arg_y]
 = do dflags <- getDynFlags
      let t = cmmExprType dflags arg_x
      xlyl <- liftM CmmLocal $ newTemp t
      xlyh <- liftM CmmLocal $ newTemp t
      xhyl <- liftM CmmLocal $ newTemp t
      r    <- liftM CmmLocal $ newTemp t
      -- This generic implementation is very simple and slow. We might
      -- well be able to do better, but for now this at least works.
      let topHalf x = CmmMachOp (MO_U_Shr (wordWidth dflags)) [x, hww]
          toTopHalf x = CmmMachOp (MO_Shl (wordWidth dflags)) [x, hww]
          bottomHalf x = CmmMachOp (MO_And (wordWidth dflags)) [x, hwm]
          add x y = CmmMachOp (MO_Add (wordWidth dflags)) [x, y]
          sum = foldl1 add
          mul x y = CmmMachOp (MO_Mul (wordWidth dflags)) [x, y]
          or x y = CmmMachOp (MO_Or (wordWidth dflags)) [x, y]
          hww = CmmLit (CmmInt (fromIntegral (widthInBits (halfWordWidth dflags)))
                               (wordWidth dflags))
          hwm = CmmLit (CmmInt (halfWordMask dflags) (wordWidth dflags))
      emit $ catAGraphs
             [mkAssign xlyl
                  (mul (bottomHalf arg_x) (bottomHalf arg_y)),
              mkAssign xlyh
                  (mul (bottomHalf arg_x) (topHalf arg_y)),
              mkAssign xhyl
                  (mul (topHalf arg_x) (bottomHalf arg_y)),
              mkAssign r
                  (sum [topHalf    (CmmReg xlyl),
                        bottomHalf (CmmReg xhyl),
                        bottomHalf (CmmReg xlyh)]),
              mkAssign (CmmLocal res_l)
                  (or (bottomHalf (CmmReg xlyl))
                      (toTopHalf (CmmReg r))),
              mkAssign (CmmLocal res_h)
                  (sum [mul (topHalf arg_x) (topHalf arg_y),
                        topHalf (CmmReg xhyl),
                        topHalf (CmmReg xlyh),
                        topHalf (CmmReg r)])]
genericWordMul2Op [res_h, res_l] [arg_x, arg_y]
 = do dflags <- getDynFlags
      let t = cmmExprType dflags arg_x
      xlyl <- liftM CmmLocal $ newTemp t
      xlyh <- liftM CmmLocal $ newTemp t
      xhyl <- liftM CmmLocal $ newTemp t
      r    <- liftM CmmLocal $ newTemp t
      -- This generic implementation is very simple and slow. We might
      -- well be able to do better, but for now this at least works.
      let topHalf x = CmmMachOp (MO_U_Shr (wordWidth dflags)) [x, hww]
          toTopHalf x = CmmMachOp (MO_Shl (wordWidth dflags)) [x, hww]
          bottomHalf x = CmmMachOp (MO_And (wordWidth dflags)) [x, hwm]
          add x y = CmmMachOp (MO_Add (wordWidth dflags)) [x, y]
          sum = foldl1 add
          mul x y = CmmMachOp (MO_Mul (wordWidth dflags)) [x, y]
          or x y = CmmMachOp (MO_Or (wordWidth dflags)) [x, y]
          hww = CmmLit (CmmInt (fromIntegral (widthInBits (halfWordWidth dflags)))
                               (wordWidth dflags))
          hwm = CmmLit (CmmInt (halfWordMask dflags) (wordWidth dflags))
      emit $ catAGraphs
             [mkAssign xlyl
                  (mul (bottomHalf arg_x) (bottomHalf arg_y)),
              mkAssign xlyh
                  (mul (bottomHalf arg_x) (topHalf arg_y)),
              mkAssign xhyl
                  (mul (topHalf arg_x) (bottomHalf arg_y)),
              mkAssign r
                  (sum [topHalf    (CmmReg xlyl),
                        bottomHalf (CmmReg xhyl),
                        bottomHalf (CmmReg xlyh)]),
              mkAssign (CmmLocal res_l)
                  (or (bottomHalf (CmmReg xlyl))
                      (toTopHalf (CmmReg r))),
              mkAssign (CmmLocal res_h)
                  (sum [mul (topHalf arg_x) (topHalf arg_y),
                        topHalf (CmmReg xhyl),
                        topHalf (CmmReg xlyh),
                        topHalf (CmmReg r)])]