diff --git a/chan.c b/chan.c
index a6792ac..3eeb9e1 100644
--- a/chan.c
+++ b/chan.c
@@ -209,13 +209,6 @@ chan_set(struct ovni_chan *chan, int st)
 	}
 }
 
-void
-chan_enable_and_set(struct ovni_chan *chan, int st)
-{
-	chan_enable(chan, 1);
-	chan_set(chan, st);
-}
-
 void
 chan_push(struct ovni_chan *chan, int st)
 {
diff --git a/chan.h b/chan.h
index de98cc9..2fdfd0d 100644
--- a/chan.h
+++ b/chan.h
@@ -56,9 +56,6 @@ chan_is_enabled(struct ovni_chan *chan);
 void
 chan_set(struct ovni_chan *chan, int st);
 
-void
-chan_enable_and_set(struct ovni_chan *chan, int st);
-
 void
 chan_push(struct ovni_chan *chan, int st);
 
diff --git a/emu.h b/emu.h
index 92176b9..019e01a 100644
--- a/emu.h
+++ b/emu.h
@@ -112,6 +112,10 @@ struct nosv_task {
 	struct ovni_ethread *thread;
 	enum nosv_task_state state;
 	UT_hash_handle hh;
+
+	/* List handle for nested task support */
+	struct nosv_task *next;
+	struct nosv_task *prev;
 };
 
 struct nosv_task_type {
@@ -284,6 +288,8 @@ struct ovni_ethread {
 
 	/* nosv task */
 	struct nosv_task *task;
+	/* nosv effective task, which is what is currently executing */
+	struct nosv_task *running_task;
 
 	/* Channels are used to output the emulator state in PRV */
 	struct ovni_chan chan[CHAN_MAX];
diff --git a/emu_nosv.c b/emu_nosv.c
index b59a133..2313477 100644
--- a/emu_nosv.c
+++ b/emu_nosv.c
@@ -16,6 +16,7 @@
  */
 
 #include "uthash.h"
+#include "utlist.h"
 
 #include "ovni.h"
 #include "emu.h"
@@ -80,7 +81,7 @@ static void
 pre_task_create(struct ovni_emu *emu)
 {
 	struct nosv_task *task, *p = NULL;
-	
+
 	task = calloc(1, sizeof(*task));
 
 	if(task == NULL)
@@ -106,8 +107,6 @@ pre_task_create(struct ovni_emu *emu)
 	/* Add the new task to the hash table */
 	HASH_ADD_INT(emu->cur_proc->tasks, id, task);
 
-	emu->cur_task = task;
-
 	dbg("new task created id=%d\n", task->id);
 }
 
@@ -138,9 +137,8 @@ pre_task_execute(struct ovni_emu *emu)
 
 	task->state = TASK_ST_RUNNING;
 	task->thread = emu->cur_thread;
-	emu->cur_thread->task = task;
-
-	emu->cur_task = task;
+	DL_PREPEND(emu->cur_thread->task, task);
+	emu->cur_thread->running_task = task;
 
 	dbg("task id=%d runs now\n", task->id);
 }
@@ -170,9 +168,9 @@ pre_task_pause(struct ovni_emu *emu)
 	if(emu->cur_thread != task->thread)
 		die("task is assigned to a different thread\n");
 
-	task->state = TASK_ST_PAUSED;
+	emu->cur_thread->running_task = NULL;
 
-	emu->cur_task = task;
+	task->state = TASK_ST_PAUSED;
 
 	dbg("task id=%d pauses\n", task->id);
 }
@@ -202,9 +200,9 @@ pre_task_resume(struct ovni_emu *emu)
 	if(emu->cur_thread != task->thread)
 		die("task is assigned to a different thread\n");
 
-	task->state = TASK_ST_RUNNING;
+	emu->cur_thread->running_task = task;
 
-	emu->cur_task = task;
+	task->state = TASK_ST_RUNNING;
 
 	dbg("task id=%d resumes\n", task->id);
 }
@@ -237,13 +235,25 @@ pre_task_end(struct ovni_emu *emu)
 
 	task->state = TASK_ST_DEAD;
 	task->thread = NULL;
-	emu->cur_thread->task = NULL;
-
-	emu->cur_task = task;
+	DL_DELETE(emu->cur_thread->task, task);
+	emu->cur_thread->running_task = emu->cur_thread->task;
 
 	dbg("task id=%d ends\n", task->id);
 }
 
+static void
+pre_task_not_running(struct ovni_emu *emu)
+{
+	struct ovni_ethread *th;
+	th = emu->cur_thread;
+
+	chan_set(&th->chan[CHAN_NOSV_TASKID], 0);
+	chan_set(&th->chan[CHAN_NOSV_TYPEID], 0);
+	chan_set(&th->chan[CHAN_NOSV_APPID], 0);
+
+	chan_pop(&th->chan[CHAN_NOSV_SUBSYSTEM], ST_NOSV_TASK_RUNNING);
+}
+
 static void
 pre_task_running(struct ovni_emu *emu, struct nosv_task *task)
 {
@@ -273,28 +283,35 @@ pre_task_running(struct ovni_emu *emu, struct nosv_task *task)
 }
 
 static void
-pre_task_not_running(struct ovni_emu *emu)
+pre_task_switch(struct ovni_emu *emu, struct nosv_task *prev_task, struct nosv_task *next_task)
 {
 	struct ovni_ethread *th;
+	struct ovni_eproc *proc;
+
+	assert(prev_task);
+	assert(next_task);
+	assert(prev_task != next_task);
 
 	th = emu->cur_thread;
+	proc = emu->cur_proc;
 
-	chan_set(&th->chan[CHAN_NOSV_TASKID], 0);
-	chan_set(&th->chan[CHAN_NOSV_TYPEID], 0);
-	chan_set(&th->chan[CHAN_NOSV_APPID], 0);
+	assert(next_task->id > 0);
+	assert(next_task->type_id > 0);
+	assert(proc->appid > 0);
 
-	if(emu->cur_loom->rank_enabled)
-		chan_set(&th->chan[CHAN_NOSV_RANK], 0);
+	chan_set(&th->chan[CHAN_NOSV_TASKID], next_task->id);
 
-	chan_pop(&th->chan[CHAN_NOSV_SUBSYSTEM], ST_NOSV_TASK_RUNNING);
+	if (prev_task->type_id != next_task->type_id)
+		chan_set(&th->chan[CHAN_NOSV_TYPEID], next_task->type_id);
 }
 
 static void
 pre_task(struct ovni_emu *emu)
 {
-	struct nosv_task *task;
+	struct nosv_task *prev_task, *next_task;
 
-	task = emu->cur_task;
+	assert(emu->cur_thread);
+	prev_task = emu->cur_thread->running_task;
 
 	switch(emu->cur_ev->header.value)
 	{
@@ -307,19 +324,16 @@ pre_task(struct ovni_emu *emu)
 			  abort();
 	}
 
-	switch(emu->cur_ev->header.value)
-	{
-		case 'x':
-		case 'r':
-			pre_task_running(emu, task);
-			break;
-		case 'p':
-		case 'e':
+	next_task = emu->cur_thread->running_task;
+
+	// Unless we're creating a task, register the switch
+	if (emu->cur_ev->header.value != 'c') {
+		if(!next_task)
 			pre_task_not_running(emu);
-			break;
-		case 'c':
-		default:
-			break;
+		else if(!prev_task)
+			pre_task_running(emu, next_task);
+		else
+			pre_task_switch(emu, prev_task, next_task);
 	}
 }
 
@@ -350,7 +364,7 @@ pre_type_create(struct ovni_emu *emu)
 		err("A task type with id %d already exists\n", *typeid);
 		abort();
 	}
-	
+
 	type = calloc(1, sizeof(*type));
 
 	if(type == NULL)