Pointer Tagging

[ghc-hetmet.git] / compiler / codeGen / Bitmap.hs

diff --git a/compiler/codeGen/Bitmap.hs b/compiler/codeGen/Bitmap.hs
index c0b4909..2e77014 100644 (file)
--- a/compiler/codeGen/Bitmap.hs
+++ b/compiler/codeGen/Bitmap.hs
@@ -1,5 +1,5 @@
 --
--- (c) The University of Glasgow 2003
+-- (c) The University of Glasgow 2003-2006
 -- 
 
 -- Functions for constructing bitmaps, which are used in various
@@ -17,7 +17,8 @@ module Bitmap (
 
 import SMRep
 import Constants
-import DATA_BITS
+
+import Data.Bits
 
 {-|
 A bitmap represented by a sequence of 'StgWord's on the /target/
@@ -37,7 +38,7 @@ chunkToBitmap chunk =
   foldr (.|.) 0 [ 1 `shiftL` n | (True,n) <- zip chunk [0..] ]
 
 -- | Make a bitmap where the slots specified are the /ones/ in the bitmap.
--- eg. @[1,2,4], size 4 ==> 0xb@.
+-- eg. @[0,1,3], size 4 ==> 0xb@.
 --
 -- The list of @Int@s /must/ be already sorted.
 intsToBitmap :: Int -> [Int] -> Bitmap
@@ -50,7 +51,7 @@ intsToBitmap size slots{- must be sorted -}
    where (these,rest) = span (<wORD_SIZE_IN_BITS) slots
 
 -- | Make a bitmap where the slots specified are the /zeros/ in the bitmap.
--- eg. @[1,2,4], size 4 ==> 0x8@  (we leave any bits outside the size as zero,
+-- eg. @[0,1,3], size 4 ==> 0x4@  (we leave any bits outside the size as zero,
 -- just to make the bitmap easier to read).
 --
 -- The list of @Int@s /must/ be already sorted.