corelogic: timeline module

migen/corelogic/timeline.py

@@ -0,0 +1,33 @@
+from migen.fhdl import structure as f
+
+class Inst:
+	def __init__(self, trigger, events):
+		self.trigger = trigger
+		self.events = events
+		self.lastevent = max([e[0] for e in events] + [e[2] for e in events if len(e) == 3])
+		f.Declare(self, "_counter", f.BV(f.BitsFor(self.lastevent)))
+	
+	def GetFragment(self):
+		counterlogic = f.If(self._counter != f.Constant(0, self._counter.bv), 
+			[f.Assign(self._counter, self._counter + f.Constant(1, self._counter.bv))],
+			[f.If(self.trigger, [f.Assign(self._counter, f.Constant(1, self._counter.bv))])])
+		# insert counter reset if it doesn't automatically overflow
+		# (test if self.lastevent+1 is a power of 2)
+		if (self.lastevent & (self.lastevent + 1)) != 0:
+			counterlogic = f.If(self._counter == self.lastevent,
+				[f.Assign(self._counter, f.Constant(0, self._counter.bv))],
+				[counterlogic])
+		def getcond(e):
+			if len(e) == 3:
+				if e[0] == 0:
+					return self.trigger & (self._counter <= f.Constant(e[2], self._counter.bv))
+				else:
+					return (self._counter >= f.Constant(e[0], self._counter.bv)) & (self._counter <= f.Constant(e[2], self._counter.bv))
+			else:
+				if e[0] == 0:
+					return self.trigger
+				else:
+					return self._counter == f.Constant(e[0], self._counter.bv)
+		sync = [f.If(getcond(e), e[1]) for e in self.events]
+		sync.append(counterlogic)
+		return f.Fragment(sync=sync)