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actorlib/misc/IntSequence: add offset feature

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This commit is contained in:
Sebastien Bourdeauducq 2012-07-07 00:10:23 +02:00
parent 518501c493
commit 0b19112f8f
1 changed files with 18 additions and 7 deletions
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25
migen/actorlib/misc.py
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@ -5,13 +5,18 @@ from migen.flow.actor import *
# Generates integers from start to maximum-1
class IntSequence(Actor):
def __init__(self, nbits, step=1):
def __init__(self, nbits, offsetbits=0, step=1):
self.nbits = nbits
self.offsetbits = offsetbits
self.step = step
parameters_layout = [("maximum", BV(self.nbits))]
if self.offsetbits:
parameters_layout.append(("offset", BV(self.offsetbits)))
super().__init__(
("maximum", Sink, [("value", BV(nbits))]),
("source", Source, [("value", BV(nbits))]))
("parameters", Sink, parameters_layout),
("source", Source, [("value", BV(max(self.nbits, self.offsetbits)))]))
def get_fragment(self):
load = Signal()
@ -19,6 +24,8 @@ class IntSequence(Actor):
last = Signal()
maximum = Signal(BV(self.nbits))
if self.offsetbits:
offset = Signal(BV(self.offsetbits))
counter = Signal(BV(self.nbits))
if self.step > 1:
@ -28,7 +35,8 @@ class IntSequence(Actor):
sync = [
If(load,
counter.eq(0),
maximum.eq(self.token("maximum").value)
maximum.eq(self.token("parameters").maximum),
offset.eq(self.token("parameters").offset) if self.offsetbits else None
).Elif(ce,
If(last,
counter.eq(0)
@ -37,14 +45,17 @@ class IntSequence(Actor):
)
)
]
comb.append(self.token("source").value.eq(counter))
if self.offsetbits:
comb.append(self.token("source").value.eq(counter + offset))
else:
comb.append(self.token("source").value.eq(counter))
counter_fragment = Fragment(comb, sync)
fsm = FSM("IDLE", "ACTIVE")
fsm.act(fsm.IDLE,
load.eq(1),
self.endpoints["maximum"].ack.eq(1),
If(self.endpoints["maximum"].stb, fsm.next_state(fsm.ACTIVE))
self.endpoints["parameters"].ack.eq(1),
If(self.endpoints["parameters"].stb, fsm.next_state(fsm.ACTIVE))
)
fsm.act(fsm.ACTIVE,
self.busy.eq(1),