From 22b3c11b93436d9f15459ce3380aec82776a1053 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Tue, 6 Mar 2012 15:00:02 +0100
Subject: [PATCH] sim: clean startup/shutdown

---
 examples/basic_sim.py | 16 ++++++++++++----
 migen/sim/generic.py  | 10 +++++-----
 migen/sim/icarus.py   |  4 +++-
 migen/sim/ipc.py      |  2 ++
 vpi/ipc.c             |  9 ++++++++-
 vpi/main.c            | 22 +++++++++++++---------
 6 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/examples/basic_sim.py b/examples/basic_sim.py
index 332881d3..55db802c 100644
--- a/examples/basic_sim.py
+++ b/examples/basic_sim.py
@@ -4,16 +4,24 @@ from migen.sim.icarus import Runner
 
 class Counter:
 	def __init__(self):
+		self.ce = Signal()
 		self.count = Signal(BV(4))
 	
 	def do_simulation(self, s, cycle):
+		if cycle % 2:
+			s.wr(self.ce, 0)
+		else:
+			s.wr(self.ce, 1)
 		print("Cycle: " + str(cycle) + " Count: " + str(s.rd(self.count)))
 	
 	def get_fragment(self):
-		sync = [self.count.eq(self.count + 1)]
+		sync = [If(self.ce, self.count.eq(self.count + 1))]
 		sim = [self.do_simulation]
 		return Fragment(sync=sync, sim=sim)
 
-dut = Counter()
-sim = Simulator(dut.get_fragment(), Runner())
-sim.run(10)
+def main():
+	dut = Counter()
+	sim = Simulator(dut.get_fragment(), Runner())
+	sim.run(10)
+
+main()
diff --git a/migen/sim/generic.py b/migen/sim/generic.py
index 56e82f73..db9978a6 100644
--- a/migen/sim/generic.py
+++ b/migen/sim/generic.py
@@ -75,19 +75,19 @@ class Simulator:
 		self.sim_runner = sim_runner
 		self.sim_runner.start(c_top, c_fragment)
 		self.ipc.accept()
-		
-		self.fragment.call_sim(self, 0)
-		self.ipc.send(MessageGo())
+		reply = self.ipc.recv()
+		assert(isinstance(reply, MessageTick))
+		self.fragment.call_sim(self, -1)
 	
 	def run(self, ncycles=-1):
 		counter = 0
 		while not self.interrupt and (ncycles < 0 or counter < ncycles):
+			self.ipc.send(MessageGo())
 			reply = self.ipc.recv()
 			assert(isinstance(reply, MessageTick))
+			self.fragment.call_sim(self, self.cycle_counter)
 			self.cycle_counter += 1
 			counter += 1
-			self.fragment.call_sim(self, self.cycle_counter)
-			self.ipc.send(MessageGo())
 
 	def rd(self, signal):
 		name = self.top_level.top_name + "." \
diff --git a/migen/sim/icarus.py b/migen/sim/icarus.py
index 680cacf1..0661c307 100644
--- a/migen/sim/icarus.py
+++ b/migen/sim/icarus.py
@@ -20,9 +20,11 @@ class Runner:
 		_str2file(self.top_file, c_top)
 		_str2file(self.dut_file, c_dut)
 		subprocess.check_call(["iverilog", "-o", self.vvp_file, self.top_file, self.dut_file] + self.extra_files)
-		subprocess.Popen(["vvp", "-mmigensim", self.vvp_file])
+		self.process = subprocess.Popen(["vvp", "-mmigensim", self.vvp_file])
 
 	def __del__(self):
+		if hasattr(self, "process"):
+			self.process.wait()
 		if not self.keep_files:
 			for f in [self.top_file, self.dut_file, self.vvp_file]:
 				try:
diff --git a/migen/sim/ipc.py b/migen/sim/ipc.py
index 0e45af27..9464a12c 100644
--- a/migen/sim/ipc.py
+++ b/migen/sim/ipc.py
@@ -145,7 +145,9 @@ class Initiator:
 
 	def __del__(self):
 		if hasattr(self, "conn"):
+			self.conn.shutdown(socket.SHUT_RDWR)
 			self.conn.close()
 		if hasattr(self, "socket"):
+			self.socket.shutdown(socket.SHUT_RDWR)
 			self.socket.close()
 		self._cleanup_file()
diff --git a/vpi/ipc.c b/vpi/ipc.c
index 9b3e5299..c78fd20e 100644
--- a/vpi/ipc.c
+++ b/vpi/ipc.c
@@ -64,6 +64,11 @@ enum {
 
 #define MAX_LEN 2048
 
+/*
+ * 0 -> error
+ * 1 -> success
+ * 2 -> graceful shutdown
+ */
 int ipc_receive(struct ipc_softc *sc)
 {
 	char buffer[MAX_LEN];
@@ -71,7 +76,9 @@ int ipc_receive(struct ipc_softc *sc)
 	int i;
 	
 	l = recv(sc->socket, buffer, MAX_LEN, 0);
-	if((l <= 0) || (l >= MAX_LEN))
+	if(l == 0)
+		return 2;
+	if((l < 0) || (l >= MAX_LEN))
 		return 0;
 	
 	i = 0;
diff --git a/vpi/main.c b/vpi/main.c
index 44fc21ce..0157df1f 100644
--- a/vpi/main.c
+++ b/vpi/main.c
@@ -105,10 +105,13 @@ static int h_read(char *name, void *user)
 
 static int process_until_go(struct migensim_softc *sc)
 {
+	int r;
+	
 	sc->has_go = 0;
 	while(!sc->has_go) {
-		if(!ipc_receive(sc->ipc))
-			return 0;
+		r = ipc_receive(sc->ipc);
+		if(r != 1)
+			return r;
 	}
 	return 1;
 }
@@ -134,25 +137,26 @@ static PLI_INT32 connect_calltf(PLI_BYTE8 *user)
 		return 0;
 	}
 	
-	if(!process_until_go(sc)) {
-		vpi_control(vpiFinish, 1);
-		return 0;
-	}
-	
 	return 0;
 }
 
 static PLI_INT32 tick_calltf(PLI_BYTE8 *user)
 {
 	struct migensim_softc *sc = (struct migensim_softc *)user;
+	int r;
 	
 	if(!ipc_tick(sc->ipc)) {
 		perror("ipc_tick");
 		vpi_control(vpiFinish, 1);
+		ipc_destroy(sc->ipc);
+		sc->ipc = NULL;
 		return 0;
 	}
-	if(!process_until_go(sc)) {
-		vpi_control(vpiFinish, 1);
+	r = process_until_go(sc);
+	if(r != 1) {
+		vpi_control(vpiFinish, r == 2 ? 0 : 1);
+		ipc_destroy(sc->ipc);
+		sc->ipc = NULL;
 		return 0;
 	}
 	
-- 
2.30.2