[project @ 2001-02-22 16:10:12 by rrt]

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

diff --git a/ghc/lib/std/Random.lhs b/ghc/lib/std/Random.lhs
index 0064315..920d986 100644 (file)
--- a/ghc/lib/std/Random.lhs
+++ b/ghc/lib/std/Random.lhs
@@ -1,7 +1,10 @@
+% ------------------------------------------------------------------------------
+% $Id: Random.lhs,v 1.22 2001/02/22 13:17:59 simonpj Exp $
 %
-% (c) The GRASP/AQUA Project, Glasgow University, 1995-99
+% (c) The University of Glasgow, 1995-2000
 %
 
+\section[Random]{Module @Random@}
 
 The June 1988 (v31 #6) issue of the Communications of the ACM has an
 article by Pierre L'Ecuyer called, "Efficient and Portable Combined
@@ -30,18 +33,24 @@ module Random
 
 #ifndef __HUGS__
 import PrelGHC         ( RealWorld )
-import PrelNum         ( fromInt )
 import PrelShow                ( showSignedInt, showSpace )
 import PrelRead                ( readDec )
 import PrelIOBase      ( unsafePerformIO, stToIO )
-import PrelArr         ( MutableVar, newVar, readVar, writeVar )
+import PrelArr         ( STRef, newSTRef, readSTRef, writeSTRef )
 import PrelReal                ( toInt )
-import CPUTime         ( getCPUTime )
 import PrelFloat       ( float2Double, double2Float )
 import Time            ( getClockTime, ClockTime(..) )
+#else
+import PrelPrim                ( IORef
+                       , newIORef
+                       , readIORef
+                       , writeIORef
+                       , unsafePerformIO
+                       )
 #endif
 
-import Char ( isSpace, chr, ord )
+import CPUTime         ( getCPUTime )
+import Char            ( isSpace, chr, ord )
 \end{code}
 
 \begin{code}
@@ -184,7 +193,9 @@ instance Random Float where
 \begin{code}
 #ifdef __HUGS__
 mkStdRNG :: Integer -> IO StdGen
-mkStdRNG o = return (createStdGen o)
+mkStdRNG o = do
+    ct          <- getCPUTime
+    return (createStdGen (ct + o))
 #else
 mkStdRNG :: Integer -> IO StdGen
 mkStdRNG o = do
@@ -207,7 +218,7 @@ randomIvalInteger (l,h) rng
           let
           (x,g')   = next g
          in
-         f (n-1) (fromInt x + acc * b) g'
+         f (n-1) (fromIntegral x + acc * b) g'
 
 randomIvalDouble :: (RandomGen g, Fractional a) => (Double, Double) -> (Double -> a) -> g -> (a, g)
 randomIvalDouble (l,h) fromDouble rng 
@@ -270,20 +281,20 @@ getStdGen :: IO StdGen
 getStdGen  = readIORef theStdGen
 
 theStdGen :: IORef StdGen
-theStdGen  = primRunST (newIORef (createStdGen 0))
+theStdGen  = unsafePerformIO (newIORef (createStdGen 0))
 
 #else
 
-global_rng :: MutableVar RealWorld StdGen
+global_rng :: STRef RealWorld StdGen
 global_rng = unsafePerformIO $ do
    rng <- mkStdRNG 0
-   stToIO (newVar rng)
+   stToIO (newSTRef rng)
 
 setStdGen :: StdGen -> IO ()
-setStdGen sgen = stToIO (writeVar global_rng sgen)
+setStdGen sgen = stToIO (writeSTRef global_rng sgen)
 
 getStdGen :: IO StdGen
-getStdGen = stToIO (readVar global_rng)
+getStdGen = stToIO (readSTRef global_rng)
 
 #endif