From 21eb17fc3621ff213bbc32a63c83cff354be2fe6 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Sat, 16 Jun 2012 22:41:34 +0200
Subject: [PATCH] examples/flow: Fibonacci demo

---
 examples/dataflow/fibonacci.py | 75 ++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 examples/dataflow/fibonacci.py

diff --git a/examples/dataflow/fibonacci.py b/examples/dataflow/fibonacci.py
new file mode 100644
index 00000000..f5800067
--- /dev/null
+++ b/examples/dataflow/fibonacci.py
@@ -0,0 +1,75 @@
+import sys
+
+from migen.flow.ala import *
+from migen.flow.network import *
+from migen.flow import plumbing
+from migen.actorlib.sim import *
+from migen.sim.generic import Simulator
+from migen.sim.icarus import Runner
+
+# Pushes a "1" token and then becomes transparent.
+class Init(Actor):
+	def __init__(self, nbits):
+		super().__init__(
+			("in", Sink, [("d", BV(nbits))]),
+			("out", Source, [("d", BV(nbits))]))
+	
+	def get_fragment(self):
+		done = Signal()
+		comb = [
+			self.busy.eq(~done),
+			If(done,
+				self.endpoints["in"].ack.eq(self.endpoints["out"].ack),
+				self.endpoints["out"].stb.eq(self.endpoints["in"].stb),
+				self.endpoints["out"].token.d.eq(self.endpoints["in"].token.d)
+			).Else(
+				self.endpoints["in"].ack.eq(0),
+				self.endpoints["out"].stb.eq(1),
+				self.endpoints["out"].token.d.eq(1)
+			)
+		]
+		sync = [
+			If(self.endpoints["out"].ack, done.eq(1))
+		]
+		return Fragment(comb, sync)
+
+class Dumper(SimActor):
+	def __init__(self, nbits):
+		def dumper_gen():
+			while True:
+				t = Token("result")
+				yield t
+				print(t.value["r"])
+		super().__init__(dumper_gen(),
+			("result", Sink, [("r", BV(nbits))]))
+
+def main():
+	nbits = 32
+	
+	# See:
+	# http://www.csse.monash.edu.au/~damian/Idioms/Topics/12.1.DataFlow/html/text.html
+	g = DataFlowGraph()
+	
+	adder = ActorNode(Add(BV(nbits)))
+	bufadd = ActorNode(plumbing.Buffer) # TODO FIXME: deadlocks without this buffer
+	init1 = ActorNode(Init(nbits))
+	buf1 = ActorNode(plumbing.Buffer)
+	init2 = ActorNode(Init(nbits))
+	buf2 = ActorNode(plumbing.Buffer)
+	
+	g.add_connection(adder, bufadd)
+	g.add_connection(bufadd, init1)
+	g.add_connection(init1, buf1)
+	g.add_connection(buf1, adder, sink_subr="a")
+	g.add_connection(buf1, init2)
+	g.add_connection(init2, buf2)
+	g.add_connection(buf2, adder, sink_subr="b")
+	
+	g.add_connection(bufadd, ActorNode(Dumper(nbits)))
+	
+	c = CompositeActor(g)
+	fragment = c.get_fragment()
+	sim = Simulator(fragment, Runner())
+	sim.run(100)
+	
+main()
-- 
2.30.2