Until now, {leaving,entering} was set in the first cycle _after_
{leaving,entering} a state.
This reshuffles the methods as discussed on IRC.-- Robert Jordens.
From 395c0635922edc394c1be3f88ba4f2e9b5b80738 Mon Sep 17 00:00:00 2001 From: Robert Jordens <[email protected]> Date: Thu, 21 Nov 2013 12:44:01 -0700 Subject: [PATCH] genlib/fsm: rename {entering,leaving} to after_{entering,leaving}, add before_{entering,leaving} --- examples/basic/fsm.py | 8 +++++--- migen/genlib/fsm.py | 40 ++++++++++++++++++++++++++-------------- 2 files changed, 31 insertions(+), 17 deletions(-) diff --git a/examples/basic/fsm.py b/examples/basic/fsm.py index 7dd1ba2..435aaa4 100644 --- a/examples/basic/fsm.py +++ b/examples/basic/fsm.py @@ -9,8 +9,10 @@ class Example(Module): self.submodules += myfsm myfsm.act("FOO", self.s.eq(1), NextState("BAR")) myfsm.act("BAR", self.s.eq(0), NextState("FOO")) - self.entering_foo = myfsm.entering("FOO") - self.leaving_bar = myfsm.leaving("BAR") + self.be = myfsm.before_entering("FOO") + self.ae = myfsm.after_entering("FOO") + self.bl = myfsm.before_leaving("FOO") + self.al = myfsm.after_leaving("FOO") example = Example() -print(verilog.convert(example, {example.s, example.entering_foo, example.leaving_bar})) +print(verilog.convert(example, {example.s, example.be, example.ae, example.bl, example.al})) diff --git a/migen/genlib/fsm.py b/migen/genlib/fsm.py index e4ee94f..8818fe6 100644 --- a/migen/genlib/fsm.py +++ b/migen/genlib/fsm.py @@ -35,8 +35,10 @@ class FSM(Module): self.state_aliases = dict() self.reset_state = reset_state - self.entering_signals = OrderedDict() - self.leaving_signals = OrderedDict() + self.before_entering_signals = OrderedDict() + self.before_leaving_signals = OrderedDict() + self.after_entering_signals = OrderedDict() + self.after_leaving_signals = OrderedDict() def act(self, state, *statements): if self.finalized: @@ -65,7 +67,7 @@ class FSM(Module): self.act(state, is_ongoing.eq(1)) return is_ongoing - def _entering_leaving(self, d, state): + def _get_signal(self, d, state): if state not in self.actions: self.actions[state] = [] try: @@ -75,12 +77,22 @@ class FSM(Module): d[state] = is_el return is_el - def entering(self, state): - return self._entering_leaving(self.entering_signals, state) + def before_entering(self, state): + return self._get_signal(self.before_entering_signals, state) + + def before_leaving(self, state): + return self._get_signal(self.before_leaving_signals, state) + + def after_entering(self, state): + signal = self._get_signal(self.after_entering_signals, state) + self.sync += signal.eq(self.before_entering(state)) + return signal + + def after_leaving(self, state): + signal = self._get_signal(self.after_leaving_signals, state) + self.sync += signal.eq(self.before_leaving(state)) + return signal - def leaving(self, state): - return self._entering_leaving(self.leaving_signals, state) - def do_finalize(self): nstates = len(self.actions) if self.reset_state is None: @@ -101,11 +113,11 @@ class FSM(Module): self.sync += self.state.eq(self.next_state) # drive entering/leaving signals - for state, is_entering in self.entering_signals.items(): + for state, signal in self.before_leaving_signals.items(): encoded = self.encoding[state] - self.sync += is_entering.eq((self.next_state == encoded) & (self.state != encoded)) - if reset_state in self.entering_signals: - self.entering_signals[reset_state].reset = 1 - for state, is_leaving in self.leaving_signals.items(): + self.comb += signal.eq((self.state == encoded) & ~(self.next_state == encoded)) + if reset_state in self.after_entering_signals: + self.after_entering_signals[reset_state].reset = 1 + for state, signal in self.before_entering_signals.items(): encoded = self.encoding[state] - self.sync += is_leaving.eq((self.next_state != encoded) & (self.state == encoded)) + self.comb += signal.eq(~(self.state == encoded) & (self.next_state == encoded)) -- 1.8.3.2
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