From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Sat, 17 Mar 2012 23:09:40 +0000 (+0100)
Subject: corelogic/fsm: delayed enters
X-Git-Tag: 24jan2021_ls180~2099^2~964
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5f281037691419530064eb5e5f50f926ea010649;p=litex.git

corelogic/fsm: delayed enters
---

diff --git a/migen/corelogic/fsm.py b/migen/corelogic/fsm.py
index d2d18481..9d0de3c8 100644
--- a/migen/corelogic/fsm.py
+++ b/migen/corelogic/fsm.py
@@ -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