[project @ 2000-03-23 17:45:17 by simonpj]

[ghc-hetmet.git] / ghc / lib / std / PrelNum.lhs

diff --git a/ghc/lib/std/PrelNum.lhs b/ghc/lib/std/PrelNum.lhs
index be3abc8..1ff4c98 100644 (file)
--- a/ghc/lib/std/PrelNum.lhs
+++ b/ghc/lib/std/PrelNum.lhs
@@ -169,11 +169,15 @@ remInteger ia 0
   = error "Prelude.Integral.rem{Integer}: divide by 0"
 remInteger a@(S# (-2147483648#)) b = remInteger (toBig a) b
 remInteger (S# a) (S# b) = S# (remInt# a b)
+{- Special case doesn't work, because a 1-element J# has the range
+   -(2^32-1) -- 2^32-1, whereas S# has the range -2^31 -- (2^31-1)
 remInteger ia@(S# a) (J# sb b)
   | sb ==# 1#  = S# (remInt# a (word2Int# (integer2Word# sb b)))
   | sb ==# -1# = S# (remInt# a (0# -# (word2Int# (integer2Word# sb b))))
   | 0# <# sb   = ia
   | otherwise  = S# (0# -# a)
+-}
+remInteger ia@(S# _) ib@(J# _ _) = remInteger (toBig ia) ib
 remInteger (J# sa a) (S# b)
   = case int2Integer# b of { (# sb, b #) ->
     case remInteger# sa a sb b of { (# sr, r #) ->
@@ -186,10 +190,13 @@ quotInteger ia 0
   = error "Prelude.Integral.quot{Integer}: divide by 0"
 quotInteger a@(S# (-2147483648#)) b = quotInteger (toBig a) b
 quotInteger (S# a) (S# b) = S# (quotInt# a b)
+{- Special case disabled, see remInteger above
 quotInteger (S# a) (J# sb b)
   | sb ==# 1#  = S# (quotInt# a (word2Int# (integer2Word# sb b)))
   | sb ==# -1# = S# (quotInt# a (0# -# (word2Int# (integer2Word# sb b))))
   | otherwise  = zeroInteger
+-}
+quotInteger ia@(S# _) ib@(J# _ _) = quotInteger (toBig ia) ib
 quotInteger (J# sa a) (S# b)
   = case int2Integer# b of { (# sb, b #) ->
     case quotInteger# sa a sb b of (# sq, q #) -> J# sq q }
@@ -377,10 +384,21 @@ instance  Enum Integer  where
     {-# INLINE enumFromThen #-}
     {-# INLINE enumFromTo #-}
     {-# INLINE enumFromThenTo #-}
-    enumFrom x             = build (\c _ -> enumDeltaIntegerFB          c   x 1)
-    enumFromThen x y       = build (\c _ -> enumDeltaIntegerFB          c   x (y-x))
-    enumFromTo x lim      = build (\c n -> enumDeltaToIntegerFB c n x 1     lim)
-    enumFromThenTo x y lim = build (\c n -> enumDeltaToIntegerFB c n x (y-x) lim)
+    enumFrom x             = efdInteger  x 1
+    enumFromThen x y       = efdInteger  x (y-x)
+    enumFromTo x lim      = efdtInteger x 1     lim
+    enumFromThenTo x y lim = efdtInteger x (y-x) lim
+
+
+efdInteger  = enumDeltaIntegerList
+efdtInteger = enumDeltaToIntegerList
+
+{-# RULES
+"efdInteger"           forall x y.  efdInteger x y         = build (\c _ -> enumDeltaIntegerFB c x y)
+"efdtInteger"          forall x y l.efdtInteger x y l      = build (\c n -> enumDeltaToIntegerFB c n x y l)
+"enumDeltaInteger"     enumDeltaIntegerFB   (:)    = enumDeltaIntegerList
+"enumDeltaToInteger"   enumDeltaToIntegerFB (:) [] = enumDeltaToIntegerList
+ #-}
 
 enumDeltaIntegerFB :: (Integer -> b -> b) -> Integer -> Integer -> b
 enumDeltaIntegerFB c x d = x `c` enumDeltaIntegerFB c (x+d) d
@@ -414,10 +432,6 @@ dn_list x delta lim = go (x::Integer)
                        go x | x < lim   = []
                             | otherwise = x : go (x+delta)
 
-{-# RULES
-"enumDeltaInteger"     enumDeltaIntegerFB   (:)    = enumDeltaIntegerList
-"enumDeltaToInteger"   enumDeltaToIntegerFB (:) [] = enumDeltaToIntegerList
- #-}
 \end{code}