diff --git a/Setup.lhs b/Setup.lhs
--- a/Setup.lhs
+++ b/Setup.lhs
@@ -2,6 +2,6 @@
 > import Distribution.Simple
 > import System.Cmd (system)
 
-> main = defaultMainWithHooks (defaultUserHooks { runTests = tests })
+> main = defaultMainWithHooks (simpleUserHooks { runTests = tests })
 
 > tests _ _ _ _ = system "runhaskell Tests/Properties.hs" >> return ()
diff --git a/Text/Show/ByteString/Char.hs b/Text/Show/ByteString/Char.hs
--- a/Text/Show/ByteString/Char.hs
+++ b/Text/Show/ByteString/Char.hs
diff --git a/Text/Show/ByteString/Float.hs b/Text/Show/ByteString/Float.hs
--- a/Text/Show/ByteString/Float.hs
+++ b/Text/Show/ByteString/Float.hs
diff --git a/Text/Show/ByteString/Int.hs b/Text/Show/ByteString/Int.hs
--- a/Text/Show/ByteString/Int.hs
+++ b/Text/Show/ByteString/Int.hs
diff --git a/Text/Show/ByteString/Integer.hs b/Text/Show/ByteString/Integer.hs
--- a/Text/Show/ByteString/Integer.hs
+++ b/Text/Show/ByteString/Integer.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE MagicHash, BangPatterns #-}
+{-# LANGUAGE UnboxedTuples, MagicHash, BangPatterns, CPP #-}
 
 -- ---------------------------------------------------------------------------
 -- |
@@ -15,8 +15,14 @@
 module Text.Show.ByteString.Integer where
 
 import GHC.Base
+
+#ifdef INTEGER_GMP
+import GHC.Integer.Internals
+#endif
+
 import GHC.Num
 
+
 import Data.Binary.Put
 
 import Text.Show.ByteString.Util
@@ -47,19 +53,34 @@
 splith :: Integer -> [Integer] -> [Integer]
 splith _ [    ] = error "splith: the impossible happened."
 splith p (n:ns) = case n `quotRemInteger` p of
-  (q, r) -> if q > 0
+#ifdef INTEGER_GMP
+  (# q, r #) ->
+#else
+  (q, r) -> 
+#endif
+          if q > 0
             then q : r : splitb p ns
             else r : splitb p ns
 
 splitb :: Integer -> [Integer] -> [Integer]
 splitb _ [    ] = []
 splitb p (n:ns) = case n `quotRemInteger` p of
-  (q, r) -> q : r : splitb p ns
+#ifdef INTEGER_GMP
+  (# q, r #) ->
+#else
+  (q, r) ->
+#endif
+            q : r : splitb p ns
 
 printh :: [Integer] -> Put
 printh [    ] = error "printh: the impossible happened."
 printh (n:ns) = case n `quotRemInteger` mx of
-  (q', r') -> let q = fromInteger q'
+#ifdef INTEGER_GMP
+  (# q', r' #) ->
+#else
+  (q', r') ->
+#endif
+              let q = fromInteger q'
                   r = fromInteger r'
               in if q > 0 then phead q >> pblock r >> printb ns
                           else phead r >> printb ns
@@ -67,7 +88,12 @@
 printb :: [Integer] -> Put
 printb [    ] = return ()
 printb (n:ns) = case n `quotRemInteger` mx of
-  (q', r') -> let q = fromInteger q'
+#ifdef INTEGER_GMP
+  (# q', r' #) ->
+#else
+  (q', r') ->
+#endif
+              let q = fromInteger q'
                   r = fromInteger r'
               in pblock q >> pblock r >> printb ns
 
diff --git a/bytestring-show.cabal b/bytestring-show.cabal
--- a/bytestring-show.cabal
+++ b/bytestring-show.cabal
@@ -1,31 +1,35 @@
-Name:              bytestring-show
-Version:           0.2
-License:           BSD3
-License-File:      LICENSE
-Author:            Dan Doel
-Maintainer:        Dan Doel <dan.doel@gmail.com>
-Homepage:          http://code.haskell.org/~dolio/
-Category:          Text
-Synopsis:          Efficient conversion of values into readable byte strings.
-Description:       Efficient conversion of values into readable byte strings.
-Build-Type:        Simple
-Cabal-Version:     >= 1.2
+name:              bytestring-show
+version:           0.2.1
+license:           BSD3
+license-file:      LICENSE
+author:            Dan Doel
+maintainer:        Dan Doel <dan.doel@gmail.com>
+homepage:          http://code.haskell.org/~dolio/
+category:          Text
+synopsis:          Efficient conversion of values into readable byte strings.
+description:       Efficient conversion of values into readable byte strings.
+build-type:        Simple
+cabal-version:     >= 1.2
 
-Library
-    Build-Depends: base, binary, bytestring >= 0.9, array, containers
+library
+    build-depends: base, binary, bytestring >= 0.9, array, containers
 
-    Exposed-Modules:
+    exposed-modules:
         Text.Show.ByteString
 
-    Other-Modules:
+    other-modules:
         Text.Show.ByteString.Util
         Text.Show.ByteString.Char
         Text.Show.ByteString.Int
         Text.Show.ByteString.Float
         Text.Show.ByteString.Integer
 
-    Extensions:
-        MagicHash, BangPatterns, TypeSynonymInstances
+    extensions:
+        UnboxedTuples, MagicHash, BangPatterns, TypeSynonymInstances, CPP
 
-    GHC-Options:
+    ghc-options:
         -O2 -Wall
+
+    if impl(ghc >= 6.9)
+        build-depends: integer
+        cpp-options: -DINTEGER_GMP