litex/migen/genlib/misc.py

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from migen.fhdl.std import *
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from migen.fhdl.structure import _Operator
def optree(op, operands, lb=None, ub=None, default=None):
if lb is None:
lb = 0
if ub is None:
ub = len(operands)
l = ub - lb
if l == 0:
if default is None:
raise AttributeError
else:
return default
elif l == 1:
return operands[lb]
else:
s = lb + l//2
return _Operator(op,
[optree(op, operands, lb, s, default),
optree(op, operands, s, ub, default)])
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def split(v, *counts):
r = []
offset = 0
for n in counts:
if n != 0:
r.append(v[offset:offset+n])
else:
r.append(None)
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offset += n
return tuple(r)
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def displacer(signal, shift, output, n=None, reverse=False):
if shift is None:
return output.eq(signal)
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if n is None:
n = 2**flen(shift)
w = flen(signal)
if reverse:
r = reversed(range(n))
else:
r = range(n)
l = [Replicate(shift == i, w) & signal for i in r]
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return output.eq(Cat(*l))
def chooser(signal, shift, output, n=None, reverse=False):
if shift is None:
return output.eq(signal)
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if n is None:
n = 2**flen(shift)
w = flen(output)
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cases = {}
for i in range(n):
if reverse:
s = n - i - 1
else:
s = i
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cases[i] = [output.eq(signal[s*w:(s+1)*w])]
return Case(shift, cases).makedefault()
def timeline(trigger, events):
lastevent = max([e[0] for e in events])
counter = Signal(max=lastevent+1)
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counterlogic = If(counter != 0,
counter.eq(counter + 1)
).Elif(trigger,
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counter.eq(1)
)
# insert counter reset if it doesn't naturally overflow
# (test if lastevent+1 is a power of 2)
if (lastevent & (lastevent + 1)) != 0:
counterlogic = If(counter == lastevent,
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counter.eq(0)
).Else(
counterlogic
)
def get_cond(e):
if e[0] == 0:
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return trigger & (counter == 0)
else:
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return counter == e[0]
sync = [If(get_cond(e), *e[1]) for e in events]
sync.append(counterlogic)
return sync