corelogic: timeline module

diff --git a/migen/corelogic/timeline.py b/migen/corelogic/timeline.py
new file mode 100644 (file)
index 0000000..bae4f72
--- /dev/null
+++ b/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)