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corelogic/fsm: delayed enters

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This commit is contained in:
Sebastien Bourdeauducq 2012-03-18 00:09:40 +01:00
parent a4294762d0
commit 5f28103769
1 changed files with 16 additions and 2 deletions
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18
migen/corelogic/fsm.py
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@ -1,13 +1,27 @@
from migen.fhdl.structure import *
class FSM:
def __init__(self, *states):
self._state_bv = BV(bits_for(len(states)-1))
def __init__(self, *states, delayed_enters=[]):
nstates = len(states) + sum([d[2] for d in delayed_enters])
self._state_bv = BV(bits_for(nstates-1))
self._state = Signal(self._state_bv)
self._next_state = Signal(self._state_bv)
for n, state in enumerate(states):
setattr(self, state, Constant(n, self._state_bv))
self.actions = [[] for i in range(len(states))]
for name, target, delay in delayed_enters:
target_state = getattr(self, target)
if delay:
name_state = len(self.actions)
setattr(self, name, Constant(name_state, self._state_bv))
for i in range(delay-1):
self.actions.append([self.next_state(Constant(name_state+i+1), self._state_bv)])
self.actions.append([self.next_state(target_state)])
else:
# alias
setattr(self, name, getattr(self, target_state))
def reset_state(self, state):
self._state.reset = state