diff --git a/chan.c b/chan.c
index 74244f4..e86f9eb 100644
--- a/chan.c
+++ b/chan.c
@@ -4,7 +4,7 @@
 #include "prv.h"
 
 void
-chan_init(struct ovni_chan *chan, int row, int type, FILE *prv, int64_t *clock)
+chan_init(struct ovni_chan *chan, int track, int row, int type, FILE *prv, int64_t *clock)
 {
 	chan->n = 0;
 	chan->type = type;
@@ -13,15 +13,52 @@ chan_init(struct ovni_chan *chan, int row, int type, FILE *prv, int64_t *clock)
 	chan->ev = -1;
 	chan->prv = prv;
 	chan->clock = clock;
-	chan->t = -1;
+	chan->t = *clock;
 	chan->row = row;
 	chan->dirty = 0;
+	chan->track = track;
+}
+
+void
+chan_th_init(struct ovni_ethread *th, int chan_index, int track, int row, FILE *prv, int64_t *clock)
+{
+	struct ovni_chan *chan;
+	int prvth;
+
+	chan = &th->chan[chan_index];
+	prvth = chan_to_prvtype[chan_index][1];
+
+	chan_init(chan, track, row, prvth, prv, clock);
+}
+
+void
+chan_cpu_init(struct ovni_cpu *cpu, int chan_index, int track, int row, FILE *prv, int64_t *clock)
+{
+	struct ovni_chan *chan;
+	int prvcpu;
+
+	chan = &cpu->chan[chan_index];
+	prvcpu = chan_to_prvtype[chan_index][2];
+
+	chan_init(chan, track, row, prvcpu, prv, clock);
 }
 
 void
 chan_enable(struct ovni_chan *chan, int enabled)
 {
+	/* Can be dirty */
+
+	dbg("chan_enable chan=%p enabled=%d\n", (void*) chan, enabled);
+
+	if(chan->enabled == enabled)
+	{
+		err("chan already in enabled=%d\n", enabled);
+		abort();
+	}
+
 	chan->enabled = enabled;
+	chan->t = *chan->clock;
+	chan->dirty = 1;
 }
 
 int
@@ -33,15 +70,15 @@ chan_is_enabled(struct ovni_chan *chan)
 void
 chan_set(struct ovni_chan *chan, int st)
 {
-	dbg("chan_set st=%d", st);
+	//dbg("chan_set chan=%p st=%d\n", (void*) chan, st);
 
 	assert(chan->enabled);
-	assert(chan->dirty == 0);
+	//assert(chan->dirty == 0);
 
 	if(chan->n == 0)
 		chan->n = 1;
 
-	chan->stack[chan->n] = st;
+	chan->stack[chan->n - 1] = st;
 	chan->t = *chan->clock;
 	chan->dirty = 1;
 }
@@ -49,7 +86,7 @@ chan_set(struct ovni_chan *chan, int st)
 void
 chan_push(struct ovni_chan *chan, int st)
 {
-	dbg("chan_push st=%d", st);
+	//dbg("chan_push chan=%p st=%d\n", (void*) chan, st);
 
 	assert(chan->enabled);
 	assert(chan->dirty == 0);
@@ -70,7 +107,7 @@ chan_pop(struct ovni_chan *chan, int expected_st)
 {
 	int st;
 
-	dbg("chan_pop expexted_st=%d", expected_st);
+	//dbg("chan_pop chan=%p expected_st=%d\n", (void*) chan, expected_st);
 
 	assert(chan->enabled);
 	assert(chan->dirty == 0);
@@ -100,6 +137,8 @@ chan_pop(struct ovni_chan *chan, int expected_st)
 void
 chan_ev(struct ovni_chan *chan, int ev)
 {
+	dbg("chan_ev chan=%p ev=%d\n", (void*) chan, ev);
+
 	assert(chan->enabled);
 	assert(chan->dirty == 0);
 	assert(ev >= 0);
@@ -115,6 +154,9 @@ chan_get_st(struct ovni_chan *chan)
 	if(chan->enabled == 0)
 		return chan->badst;
 
+	if(chan->n == 0)
+		return 0;
+
 	assert(chan->n > 0);
 	return chan->stack[chan->n-1];
 }
@@ -141,8 +183,6 @@ emit_st(struct ovni_chan *chan)
 {
 	int st;
 
-	assert(chan->enabled);
-
 	st = chan_get_st(chan);
 
 	prv_ev(chan->prv, chan->row, chan->t, chan->type, st);
@@ -155,6 +195,8 @@ chan_emit(struct ovni_chan *chan)
 	if(chan->dirty == 0)
 		return;
 
+	//dbg("chan_emit chan=%p\n", (void*) chan);
+
 	/* Emit badst if disabled */
 	if(chan->enabled == 0)
 	{
diff --git a/chan.h b/chan.h
index 2e60c35..3c4cbd8 100644
--- a/chan.h
+++ b/chan.h
@@ -4,7 +4,13 @@
 #include "emu.h"
 
 void
-chan_init(struct ovni_chan *chan, int row, int type, FILE *prv, int64_t *clock);
+chan_init(struct ovni_chan *chan, int track, int row, int type, FILE *prv, int64_t *clock);
+
+void
+chan_th_init(struct ovni_ethread *th, int chan_index, int track, int row, FILE *prv, int64_t *clock);
+
+void
+chan_cpu_init(struct ovni_cpu *cpu, int chan_index, int track, int row, FILE *prv, int64_t *clock);
 
 void
 chan_enable(struct ovni_chan *chan, int enabled);
diff --git a/emu.h b/emu.h
index 53dcd31..15e3ab1 100644
--- a/emu.h
+++ b/emu.h
@@ -66,6 +66,11 @@ struct nosv_task_type {
 
 #define MAX_CHAN_STACK 128
 
+enum chan_track {
+	CHAN_TRACK_NONE = 0,
+	CHAN_TRACK_TH_RUNNING,
+};
+
 struct ovni_chan {
 	/* Number of states in the stack */
 	int n;