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Allow SimActors to produce/consume a constant stream of tokens

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Currently a SimActor requires one clock period to recover from consuming or
producing a token. ack/stb are deasserted in the cycle where the token is
consumed/produced and only re-asserted in the next cycle. This patch updates the
code to keep the control signals asserted if the actor is able to produce or
consume a token in the next cycle.

The patch also sets 'initialize' attribute on the simulation method, this will
make sure that the control and data signals will be ready right on the first
clock cycle.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This commit is contained in:
Lars-Peter Clausen 2013-03-12 22:27:19 +01:00
parent 72579a6129
commit dea4674922
1 changed files with 25 additions and 18 deletions
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43
migen/actorlib/sim.py
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@ -22,27 +22,31 @@ class TokenExchanger(PureSimulable):
for token in self.active:
ep = self.actor.endpoints[token.endpoint]
if isinstance(ep, Sink):
if s.rd(ep.ack):
if s.rd(ep.stb):
token.value = s.multiread(ep.token)
completed.add(token)
s.wr(ep.ack, 0)
else:
s.wr(ep.ack, 1)
if s.rd(ep.ack) and s.rd(ep.stb):
token.value = s.multiread(ep.token)
completed.add(token)
s.wr(ep.ack, 0)
elif isinstance(ep, Source):
if s.rd(ep.stb):
if s.rd(ep.ack):
completed.add(token)
s.wr(ep.stb, 0)
else:
s.wr(ep.stb, 1)
s.multiwrite(ep.token, token.value)
if s.rd(ep.ack) and s.rd(ep.stb):
completed.add(token)
s.wr(ep.stb, 0)
else:
raise TypeError
self.active -= completed
if not self.active:
self.busy = True
def _update_control_signals(self, s):
for token in self.active:
ep = self.actor.endpoints[token.endpoint]
if isinstance(ep, Sink):
s.wr(ep.ack, 1)
elif isinstance(ep, Source):
s.multiwrite(ep.token, token.value)
s.wr(ep.stb, 1)
else:
raise TypeError
def _next_transactions(self):
try:
transactions = next(self.generator)
@ -62,13 +66,16 @@ class TokenExchanger(PureSimulable):
raise TypeError
if self.active and all(transaction.idle_wait for transaction in self.active):
self.busy = False
def do_simulation(self, s):
if not self.done:
if not self.active:
self._next_transactions()
if self.active:
self._process_transactions(s)
if not self.active:
self._next_transactions()
self._update_control_signals(s)
do_simulation.initialize = True
class SimActor(Actor):
def __init__(self, generator, *endpoint_descriptions, **misc):