litex/migen/actorlib/structuring.py

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2012-06-20 10:35:01 -04:00
from migen.fhdl.structure import *
from migen.flow.actor import *
class Cast(CombinatorialActor):
def __init__(self, layout_from, layout_to):
super().__init__(
("sink", Sink, layout_from),
("source", Source, layout_to))
def get_process_fragment(self):
sigs_from = self.token("sink").flatten()
sigs_to = self.token("source").flatten()
if sum(len(s) for s in sigs_from) != sum(len(s) for s in sigs_to):
raise TypeError
return Fragment([
Cat(*sigs_to).eq(Cat(*sigs_from))
])
class Chop(Actor):
def __init__(self, n, layout_to):
self.n = n
layout_from = [("chunk{0}".format(i), layout_to)
for i in range(self.n)]
super().__init__(
("sink", Sink, layout_from),
("source", Source, layout_to))
def get_fragment(self):
muxbits = bits_for(self.n-1)
mux = Signal(BV(muxbits))
last = Signal()
comb = [
last.eq(mux == (self.n-1)),
self.endpoints["source"].stb.eq(self.endpoints["sink"].stb),
self.endpoints["sink"].ack.eq(last & self.endpoints["source"].ack)
]
sync = [
If(self.endpoints["source"].stb & self.endpoints["source"].ack,
If(last,
mux.eq(0)
).Else(
mux.eq(mux + 1)
)
)
]
cases = [(Constant(i, BV(muxbits)),
Cat(*self.token("source").flatten()).eq(*self.token("sink").subrecord("chunk{0}".format(i)).flatten()))
for i in range(self.n)]
cases[-1][0] = Default()
comb.append(Case(mux, *cases))
return Fragment(comb, sync)
class Pack(Actor):
def __init__(self, layout_from, n):
self.n = n
layout_to = [("chunk{0}".format(i), layout_from)
for i in range(self.n)]
super().__init__(
("sink", Sink, layout_from),
("source", Source, layout_to))
def get_fragment(self):
demuxbits = bits_for(self.n-1)
demux = Signal(BV(demuxbits))
load_part = Signal()
strobe_all = Signal()
cases = [(Constant(i, BV(demuxbits)),
Cat(*self.token("source").subrecord("chunk{0}".format(i)).flatten()).eq(*self.token("sink").flatten())
for i in range(self.n)]
comb = [
self.endpoints["sink"].ack.eq(~strobe_all | self.endpoints["source"].ack),
self.endpoints["source"].stb.eq(strobe_all),
load_part.eq(self.endpoints["sink"].stb & self.endpoints["sink"].ack)
]
sync = [
If(self.endpoints["source"].ack,
strobe_all.eq(0)
),
If(load_part,
Case(demux, *cases),
If(demux == (self.n - 1),
demux.eq(0),
strobe_all.eq(1)
).Else(
demux.eq(demux + 1)
)
)
]
return Fragment(comb, sync)