Index: Python/ceval.c
===================================================================
RCS file: /home/cvs/stackless/src/Python/ceval.c,v
retrieving revision 1.10
diff -u -r1.10 ceval.c
--- Python/ceval.c	2002/06/03 20:45:41	1.10
+++ Python/ceval.c	2002/06/18 17:43:39
@@ -679,6 +679,19 @@
 			}
 #endif
 
+#ifdef STACKLESS
+                        if ( ! tstate->slp_state.switch_lock) {
+			  PyTaskletObject *task = tstate->slp_state.current;
+                          PyTaskletObject *next = (PyTaskletObject*)task->next;
+                          if (task != next && tstate->slp_state.runcount != 0) {
+			    if(slp_schedule_task(task, next)) {
+				why = WHY_EXCEPTION;
+				goto on_error;
+			    }
+			  }
+		        }
+#endif
+
 #ifdef WITH_THREAD
 			if (interpreter_lock) {
 				/* Give another thread a chance */
Index: Stackless/stackless.h
===================================================================
RCS file: /home/cvs/stackless/src/Stackless/stackless.h,v
retrieving revision 1.28
diff -u -r1.28 stackless.h
--- Stackless/stackless.h	2002/06/18 10:38:50	1.28
+++ Stackless/stackless.h	2002/06/18 17:43:39
@@ -97,6 +97,7 @@
 	struct _tasklet *client;
 	PyObject *tempval;
 	int slicing_lock;
+        int saved_switch_lock;
 } PyTaskletObject;
 
 /*** important structures: channel ***/
@@ -121,6 +122,8 @@
 	struct _tasklet *queue;
 	/* recursion control */
 	int slice_interval;
+	/* schedule lock */
+	int switch_lock;
 	/* temporary variables for slp_switch */
 	struct {
 		struct _cstack **cstprev, *cst;
@@ -146,6 +149,7 @@
 	tstate->slp_state.waitcount = 0;\
 	tstate->slp_state.queue = NULL;\
 	tstate->slp_state.slice_interval = RECURSION_LIMIT;\
+	tstate->slp_state.switch_lock = 1;\
 
 #define STACKLESS_PYSTATE_ZAP \
 	ZAP(tstate->slp_state.initial_stub);\
Index: Stackless/stacklesseval.h
===================================================================
RCS file: /home/cvs/stackless/src/Stackless/stacklesseval.h,v
retrieving revision 1.40
diff -u -r1.40 stacklesseval.h
--- Stackless/stacklesseval.h	2002/06/18 10:35:42	1.40
+++ Stackless/stacklesseval.h	2002/06/18 17:43:40
@@ -195,6 +195,7 @@
 		t->client = NULL;
 		t->tempval = NULL;
 		t->slicing_lock = 0;
+		t->saved_switch_lock = 1; /*init shouldn't matter...*/
 	}
 	return t;
 }
@@ -376,6 +377,12 @@
 	}
 	else {
 		savets.frame = NULL;
+	}
+
+        /*save switch_lock*/
+        {
+	  prev->saved_switch_lock = tstate->slp_state.switch_lock;
+          tstate->slp_state.switch_lock = target->saved_switch_lock;
 	}
 
 	tstate->slp_state.current = target;
Index: Stackless/stacklessmodule.c
===================================================================
RCS file: /home/cvs/stackless/src/Stackless/stacklessmodule.c,v
retrieving revision 1.23
diff -u -r1.23 stacklessmodule.c
--- Stackless/stacklessmodule.c	2002/06/18 10:38:50	1.23
+++ Stackless/stacklessmodule.c	2002/06/18 17:43:40
@@ -82,6 +82,7 @@
 	{"tempval", T_OBJECT, offsetof(PyTaskletObject, tempval), READONLY},
 	{"blocked", T_INT, offsetof(PyTaskletObject, blocked), READONLY},
 	{"slicing_lock", T_INT, offsetof(PyTaskletObject, slicing_lock), READONLY},\
+	{"saved_switch_lock", T_INT, offsetof(PyTaskletObject, saved_switch_lock), READONLY},\
 	{0}
 };
 
@@ -121,6 +122,24 @@
 }
 
 
+static char autoschedule_lock_doc__[] =
+"Returns current state of the tasklet scheduler lock. \
+Sets the lock to the passed state.";
+
+static PyObject *
+autoschedule_lock(PyObject *self, PyObject *args, PyObject *kwds)
+{
+	long state, ret;
+	static char *kwlist[] = {"state", NULL};
+	PyThreadState *tstate = PyThreadState_GET();
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "i:autoschedule_lock", kwlist, &state))
+		return NULL;
+
+        ret = tstate->slp_state.switch_lock;
+        tstate->slp_state.switch_lock = state;
+	return PyInt_FromLong(ret);
+}
+
 static char taskoutlet_call__doc__[] =
 "A call to this object takes the same parameters\n\
 as the wrapped function. The function is not called;\n\
@@ -580,6 +599,8 @@
 	{"getruncount",	(PyCFunction)getruncount, METH_NOARGS, getruncount__doc__},
 	{"getcurrent",	(PyCFunction)getcurrent, METH_NOARGS, getcurrent__doc__},
 	{"getmain",	(PyCFunction)getmain, METH_NOARGS, getmain__doc__},
+	{"autoschedule_lock",(PyCFunction)autoschedule_lock, 
+	        METH_VARARGS | METH_KEYWORDS, autoschedule_lock_doc__},
 #ifdef STACKLESS_SPY
 	{"_peek", (PyCFunction)_peek, METH_O, _peek__doc__},
 #endif