litex/migen/corelogic/timeline.py

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from migen.fhdl.structure import *
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class Timeline:
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def __init__(self, trigger, events):
self.trigger = trigger
self.events = events
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self.lastevent = max([e[0] for e in events])
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def get_fragment(self):
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counter = Signal(BV(bits_for(self.lastevent)))
counterlogic = If(counter != Constant(0, counter.bv),
counter.eq(counter + Constant(1, counter.bv))
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).Elif(self.trigger,
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counter.eq(Constant(1, counter.bv))
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)
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# 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:
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counterlogic = If(counter == self.lastevent,
counter.eq(Constant(0, counter.bv))
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).Else(
counterlogic
)
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def get_cond(e):
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if e[0] == 0:
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return self.trigger & (counter == Constant(0, counter.bv))
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else:
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return counter == Constant(e[0], counter.bv)
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sync = [If(get_cond(e), *e[1]) for e in self.events]
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sync.append(counterlogic)
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return Fragment(sync=sync)