On Tue, Jul 31, 2012 at 1:56 AM, Ryan Ingram
<ryani.spam@gmail.com> wrote:
Sure, but it's easy to roll your own from those primitives:
{-# LANGUAGE MagicHash, UnboxedTuples #-}
import GHC.Exts
addCarry :: Int -> Int -> (Int, Bool)
addCarry (I# x) (I# y) = case addIntC# x y of
(# s, c #) -> case c of
0# -> (I# s, False)
_ -> (I# s, True)
or something along those lines.
-- ryan
On Mon, Jul 30, 2012 at 1:43 PM, Евгений Пермяков
<permeakra@gmail.com> wrote:
On 07/31/2012 12:04 AM, Artyom Kazak wrote:
Евгений Пермяков <permeakra@gmail.com> писал в своём письме Mon, 30 Jul 2012 09:47:48 +0300:
Can someone tell me if there are any primitives, that used to detect machine type overflows, in ghc haskell ? I perfectly understand, that I can build something based on preconditioning of variables, but this will kill any performance, if needed.
In GHC.Prim — primitives addIntC# and subIntC#:
addIntC# :: Int# -> Int# -> (#Int#, Int##)
Add with carry. First member of result is (wrapped) sum; second member is 0 iff no overflow occured.
subIntC# :: Int# -> Int# -> (#Int#, Int##)
Subtract with carry. First member of result is (wrapped) difference; second member is 0 iff no overflow occured.
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Strangely enough, I found some relevant descriptions in *.pp in dev branch, so I expect them in 7.6.1. They applies to native-size Word and Int only.