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lib.fifo: simplify. NFC.

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This commit is contained in:
whitequark 2019-09-21 06:09:30 +00:00
parent a1bc2bbeb0
commit f6f0a7b692
1 changed files with 10 additions and 7 deletions
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17
nmigen/lib/fifo.py
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@ -358,12 +358,13 @@ class AsyncFIFO(Elaboratable, FIFOInterface):
m.d.comb += consume_enc.i.eq(consume_r_nxt)
m.d[self._r_domain] += consume_r_gry.eq(consume_enc.o)
w_full = Signal()
r_empty = Signal()
m.d.comb += [
self.w_rdy.eq(
(produce_w_gry[-1] == consume_w_gry[-1]) |
(produce_w_gry[-2] == consume_w_gry[-2]) |
(produce_w_gry[:-2] != consume_w_gry[:-2])),
self.r_rdy.eq(consume_r_gry != produce_r_gry)
w_full.eq((produce_w_gry[-1] != consume_w_gry[-1]) &
(produce_w_gry[-2] != consume_w_gry[-2]) &
(produce_w_gry[:-2] == consume_w_gry[:-2])),
r_empty.eq(consume_r_gry == produce_r_gry),
]
storage = Memory(self.width, self.depth)
@ -373,12 +374,14 @@ class AsyncFIFO(Elaboratable, FIFOInterface):
m.d.comb += [
w_port.addr.eq(produce_w_bin[:-1]),
w_port.data.eq(self.w_data),
w_port.en.eq(do_write)
w_port.en.eq(do_write),
self.w_rdy.eq(~w_full),
]
m.d.comb += [
r_port.addr.eq((consume_r_bin + do_read)[:-1]),
r_port.addr.eq(consume_r_nxt[:-1]),
self.r_data.eq(r_port.data),
r_port.en.eq(1),
self.r_rdy.eq(~r_empty),
]
if platform == "formal":