--- a/AbstractOperatingSystem.st	Fri Dec 23 13:41:34 2011 +0000
+++ b/AbstractOperatingSystem.st	Fri Jan 06 08:53:28 2012 +0000
@@ -5414,6 +5414,50 @@
     aBlock value:hours value:minutes value:seconds value:millis
 !
 
+getCPUCycleCount
+    "get a CPU specific cycle counter value.
+     Can be used for exact timing & performance measurements.
+     Notice, that the # of cycles has to be multiplied by the cycle time (1/cpu-frequency).
+
+     For x86:
+        the CPU cycle count register value is returned (RDTSC instruction).
+        Fails if RDTSC instruction is not supported (which is unlikely, nowadays).
+     For others:
+        currently fails"
+
+%{  /* NOCONTEXT */
+    unsigned int low, high;
+
+#ifdef i386
+    // use RDTSC instruction (retrieves 64bit cycle count; hi in EDX, lo in EAX)
+
+# if defined(__BORLANDC__)
+    _asm { push edx };
+    __emit__(0x0F,0x31);            /* RDTSC instruction */
+    _asm { mov low,eax };          
+    _asm { mov high,edx };
+    _asm { pop edx };
+# elif defined(_MSC_VER)
+    _asm { push  edx };
+    _asm { _emit 0fh }; _asm { _emit 031h };
+    _asm { mov low,eax };          
+    _asm { mov high,edx };
+    _asm { pop   edx };
+# elif defined(__MINGW_H) || defined(__GNUC__)
+    asm volatile("rdtsc" : "=a"(low), "=d"(high));
+# else
+    goto unsupported;
+# endif
+#endif /* i386 */
+
+    RETURN ( __MKLARGEINT64(1, low, high) );
+unsupported: ;
+%}.
+    self primitiveFailed:'no CPU cycle register on this architecture'
+
+    "Created: / 05-01-2012 / 13:23:31 / cg"
+!
+
 getMicrosecondTime
     "This returns the microsecond timers value - if available.
      On some machines, times with this precision may not be available,
@@ -7058,16 +7102,17 @@
 !AbstractOperatingSystem class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic/AbstractOperatingSystem.st,v 1.215 2011/10/27 16:31:24 stefan Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic/AbstractOperatingSystem.st,v 1.216 2012/01/05 13:08:45 cg Exp $'
 !
 
 version_CVS
-    ^ 'Header: /cvs/stx/stx/libbasic/AbstractOperatingSystem.st,v 1.215 2011/10/27 16:31:24 stefan Exp '
+    ^ 'Header: /cvs/stx/stx/libbasic/AbstractOperatingSystem.st,v 1.216 2012/01/05 13:08:45 cg Exp '
 !
 
 version_SVN
-    ^ '$Id: AbstractOperatingSystem.st 10729 2011-10-31 22:19:21Z vranyj1 $'
+    ^ '$Id: AbstractOperatingSystem.st 10754 2012-01-06 08:53:28Z vranyj1 $'
 ! !
 
 AbstractOperatingSystem initialize!
 
+