cgOp (LFloatInt ITBig) [x] = do
  x' <- unbox (FArith ATFloat) x
  z  <- alloc mpzTy
  inst' $ simpleCall "__gmpz_init" [z]
  inst' $ simpleCall "__gmpz_set_d" [ z, x' ]
  box (FArith (ATInt ITBig)) z
cgOp (LFloatInt ITBig) [x] = do
  x' <- unbox (FArith ATFloat) x
  z  <- alloc mpzTy
  inst' $ simpleCall "__gmpz_init" [z]
  inst' $ simpleCall "__gmpz_set_d" [ z, x' ]
  box (FArith (ATInt ITBig)) z
cgOp (LFloatInt ITBig) [x] = do
  x' <- unbox (FArith ATFloat) x
  z  <- alloc mpzTy
  inst' $ simpleCall "__gmpz_init" [z]
  inst' $ simpleCall "__gmpz_set_d" [ z, x' ]
  box (FArith (ATInt ITBig)) z