--- a/ProcessorScheduler.st	Wed Feb 08 04:10:51 1995 +0100
+++ b/ProcessorScheduler.st	Wed Feb 08 04:11:17 1995 +0100
@@ -23,6 +23,7 @@
 			     UserSchedulingPriority 
 			     UserInterruptPriority
 			     TimingPriority
+			     HighestPriority
 			     SchedulingPriority'
 	 poolDictionaries:''
 	 category:'Kernel-Processes'
@@ -32,7 +33,7 @@
 COPYRIGHT (c) 1993 by Claus Gittinger
 	     All Rights Reserved
 
-$Header: /cvs/stx/stx/libbasic/ProcessorScheduler.st,v 1.27 1995-02-05 21:33:24 claus Exp $
+$Header: /cvs/stx/stx/libbasic/ProcessorScheduler.st,v 1.28 1995-02-08 03:11:03 claus Exp $
 '!
 
 Smalltalk at:#Processor put:nil!
@@ -55,7 +56,7 @@
 
 version
 "
-$Header: /cvs/stx/stx/libbasic/ProcessorScheduler.st,v 1.27 1995-02-05 21:33:24 claus Exp $
+$Header: /cvs/stx/stx/libbasic/ProcessorScheduler.st,v 1.28 1995-02-08 03:11:03 claus Exp $
 "
 !
 
@@ -91,19 +92,26 @@
 
 	KnownProcesses          <Collection>    all known processes
 	KnownProcessIds         <Collection>    and their IDs
+
 	PureEventDriven         <Boolean>       true, if no process support
 						is available
+
 	UserSchedulingPriority  <Integer>       the priority at which normal
 						user interfaces run
+
 	UserInterruptPriority                   the priority at which user-
 						interrupts (Cntl-C) processing
 						takes place. Processes with
 						a greater or equal priority are
 						not interruptable.
+
 	TimingPriority                          the priority used for timing.
 						Processes with a greater or
 						equal priority are not interrupted
 						by timers.
+
+	HighestPriority                         The highest allowed prio for processes
+
 	SchedulingPriority                      The priority of the scheduler (must
 						me higher than any other).
 
@@ -134,6 +142,7 @@
     UserInterruptPriority := 24.
     TimingPriority := 16.
     SchedulingPriority := 31.
+    HighestPriority := 30.
 
     Processor isNil ifTrue:[
 	"create the one and only processor"
@@ -306,12 +315,9 @@
     activeProcess := aProcess.
     currentPriority := pri.
 %{
-    extern OBJ __threadSwitch(), __threadSwitchWithSingleStep();
+    extern OBJ ___threadSwitch();
 
-    if (singleStep == true)
-	ok = __threadSwitchWithSingleStep(__context, _intVal(id));
-    else
-	ok = __threadSwitch(__context, _intVal(id));
+    ok = ___threadSwitch(__context, _intVal(id), (singleStep == true) ? 1 : 0);
 %}.
     "time passes spent in some other process ...
      ... here again"
@@ -368,7 +374,7 @@
     "must be below schedulingPriority - 
      otherwise scheduler could be blocked ...
     "
-    ^ SchedulingPriority - 1  
+    ^ HighestPriority  
 !
 
 schedulingPriority
@@ -602,16 +608,16 @@
      check if the running process is not the only one
     "
     l size ~~ 1 ifTrue:[
-        "
-         bring running process to the end
-        "
-        l removeFirst.
-        l addLast:activeProcess.
+	"
+	 bring running process to the end
+	"
+	l removeFirst.
+	l addLast:activeProcess.
 
-        "
-         and switch to first in the list
-        "
-        self threadSwitch:(l first).
+	"
+	 and switch to first in the list
+	"
+	self threadSwitch:(l first).
     ].
     wasBlocked ifFalse:[OperatingSystem unblockInterrupts].
 !
@@ -877,8 +883,8 @@
 	newPrio := 1.
     ] ifFalse:[
 	aProcess == scheduler ifTrue:[^ self].
-	newPrio >= SchedulingPriority ifTrue:[
-	    newPrio := SchedulingPriority - 1
+	newPrio > HighestPriority ifTrue:[
+	    newPrio := HighestPriority
 	]
     ].
 
@@ -954,17 +960,18 @@
 highestPriorityRunnableProcess
     "return the highest prio runnable process"
 
-    |l p maxPri "{ Class: SmallInteger }" |
+    |listArray l p maxPri "{ Class: SmallInteger }" |
 
-    maxPri := self highestPriority.
+    maxPri := HighestPriority.
+    listArray := quiescentProcessLists.
     maxPri to:1 by:-1 do:[:prio |
-	l := quiescentProcessLists at:prio.
+	l := listArray at:prio.
 	l notNil ifTrue:[
 	    l isEmpty ifTrue:[
 		"
 		 on the fly clear out empty lists
 		"
-		quiescentProcessLists at:prio put:nil
+		listArray at:prio put:nil
 	    ] ifFalse:[    
 		p := l first.
 		"
@@ -982,18 +989,27 @@
     ^ nil
 !
 
+isSystemProcess:aProcess
+    "return true if aProcess is a system process,
+     which should not be suspended/terminated etc.."
+
+    (self class isPureEventDriven 
+    or:[aProcess id == 0
+    or:[aProcess nameOrId endsWith:'dispatcher']]) ifTrue:[
+	^ true
+    ].
+    ^ false
+
+    "
+     Processor activeProcessIsSystemProcess
+    "
+!
+
 activeProcessIsSystemProcess
     "return true if the active process is a system process,
      which should not be suspended."
 
-    |active|
-
-    (self class isPureEventDriven 
-    or:[(active := self activeProcess) id == 0
-    or:[active nameOrId endsWith:'dispatcher']]) ifTrue:[
-	^ true
-    ].
-    ^ false
+    ^ self isSystemProcess:activeProcess
 
     "
      Processor activeProcessIsSystemProcess