X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=System%2FCPUTime.hsc;h=132b041588a8886d1b74a90079223a65a186c50f;hb=22038e70e9e89dc199bf9986e35217847064ff73;hp=b9678a3d50d98070defc67996e43ae0cc400a99e;hpb=4f4fbd185f6cea77eb28407b1eadcca2673c6382;p=haskell-directory.git

diff --git a/System/CPUTime.hsc b/System/CPUTime.hsc
index b9678a3..132b041 100644
--- a/System/CPUTime.hsc
+++ b/System/CPUTime.hsc
@@ -26,6 +26,10 @@ import Data.Ratio
 import Hugs.Time ( getCPUTime, clockTicks )
 #endif
 
+#ifdef __NHC__
+import CPUTime ( getCPUTime, cpuTimePrecision )
+#endif
+
 #ifdef __GLASGOW_HASKELL__
 import Foreign
 import Foreign.C
@@ -87,6 +91,8 @@ foreign import ccall unsafe times :: Ptr CTms -> IO CClock
 #endif
 
 #else /* win32 */
+     -- NOTE: GetProcessTimes() is only supported on NT-based OSes.
+     -- The counts reported by GetProcessTimes() are in 100-ns (10^-7) units.
     allocaBytes (#const sizeof(FILETIME)) $ \ p_creationTime -> do
     allocaBytes (#const sizeof(FILETIME)) $ \ p_exitTime -> do
     allocaBytes (#const sizeof(FILETIME)) $ \ p_kernelTime -> do
@@ -96,11 +102,15 @@ foreign import ccall unsafe times :: Ptr CTms -> IO CClock
     if toBool ok then do
       ut <- ft2psecs p_userTime
       kt <- ft2psecs p_kernelTime
-      return (fromIntegral (ut + kt))
+      return (ut + kt)
      else return 0
-  where ft2psecs ft = do
+  where 
+	ft2psecs :: Ptr FILETIME -> IO Integer
+        ft2psecs ft = do
           high <- (#peek FILETIME,dwHighDateTime) ft :: IO CLong
           low <- (#peek FILETIME,dwLowDateTime) ft :: IO CLong
+	    -- Convert 100-ns units to picosecs (10^-12) 
+	    -- => multiply by 10^5.
           return (((fromIntegral high) * (2^32) + (fromIntegral low)) * 100000)
 
     -- ToDo: pin down elapsed times to just the OS thread(s) that
@@ -119,8 +129,10 @@ foreign import ccall unsafe "GetProcessTimes" getProcessTimes :: Ptr HANDLE -> P
 -- in CPU time that the implementation can record, and is given as an
 -- integral number of picoseconds.
 
+#ifndef __NHC__
 cpuTimePrecision :: Integer
 cpuTimePrecision = round ((1000000000000::Integer) % fromIntegral (clockTicks))
+#endif
 
 #ifdef __GLASGOW_HASKELL__
 clockTicks :: Int