75 lines
2.5 KiB
Python
75 lines
2.5 KiB
Python
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import warnings
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from ..._utils import deprecated
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from ...lib.cdc import FFSynchronizer as NativeFFSynchronizer
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from ...lib.cdc import PulseSynchronizer as NativePulseSynchronizer
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from ...hdl.ast import *
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from ..fhdl.module import CompatModule
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from ..fhdl.structure import If
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__all__ = ["MultiReg", "PulseSynchronizer", "GrayCounter", "GrayDecoder"]
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class MultiReg(NativeFFSynchronizer):
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def __init__(self, i, o, odomain="sync", n=2, reset=0):
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old_opts = []
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new_opts = []
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if odomain != "sync":
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old_opts.append(", odomain={!r}".format(odomain))
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new_opts.append(", o_domain={!r}".format(odomain))
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if n != 2:
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old_opts.append(", n={!r}".format(n))
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new_opts.append(", stages={!r}".format(n))
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warnings.warn("instead of `MultiReg(...{})`, use `FFSynchronizer(...{})`"
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.format("".join(old_opts), "".join(new_opts)),
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DeprecationWarning, stacklevel=2)
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super().__init__(i, o, o_domain=odomain, stages=n, reset=reset)
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self.odomain = odomain
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@deprecated("instead of `migen.genlib.cdc.PulseSynchronizer`, use `nmigen.lib.cdc.PulseSynchronizer`")
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class PulseSynchronizer(NativePulseSynchronizer):
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def __init__(self, idomain, odomain):
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super().__init__(i_domain=idomain, o_domain=odomain)
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@deprecated("instead of `migen.genlib.cdc.GrayCounter`, use `nmigen.lib.coding.GrayEncoder`")
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class GrayCounter(CompatModule):
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def __init__(self, width):
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self.ce = Signal()
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self.q = Signal(width)
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self.q_next = Signal(width)
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self.q_binary = Signal(width)
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self.q_next_binary = Signal(width)
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###
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self.comb += [
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If(self.ce,
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self.q_next_binary.eq(self.q_binary + 1)
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).Else(
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self.q_next_binary.eq(self.q_binary)
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),
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self.q_next.eq(self.q_next_binary ^ self.q_next_binary[1:])
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]
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self.sync += [
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self.q_binary.eq(self.q_next_binary),
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self.q.eq(self.q_next)
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]
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@deprecated("instead of `migen.genlib.cdc.GrayDecoder`, use `nmigen.lib.coding.GrayDecoder`")
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class GrayDecoder(CompatModule):
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def __init__(self, width):
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self.i = Signal(width)
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self.o = Signal(width, reset_less=True)
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# # #
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o_comb = Signal(width)
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self.comb += o_comb[-1].eq(self.i[-1])
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for i in reversed(range(width-1)):
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self.comb += o_comb[i].eq(o_comb[i+1] ^ self.i[i])
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self.sync += self.o.eq(o_comb)
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