+#include "MachDeps.h"
+
+#ifdef __GLASGOW_HASKELL__
+#if (WORD_SIZE_IN_BITS == 32 || WORD_SIZE_IN_BITS == 64)
+instance Show (Ptr a) where
+ showsPrec p (Ptr a) rs = pad_out (showHex (word2Integer(int2Word#(addr2Int# a))) "") rs
+ where
+ -- want 0s prefixed to pad it out to a fixed length.
+ pad_out ('0':'x':ls) rs =
+ '0':'x':(replicate (2*SIZEOF_HSPTR - length ls) '0') ++ ls ++ rs
+ -- word2Integer :: Word# -> Integer (stolen from Word.lhs)
+ word2Integer w = case word2Integer# w of
+ (# s, d #) -> J# s d
+#endif
+#endif