litex/migen/corelogic/misc.py

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from migen.fhdl.structure import *
from migen.fhdl.structure import _Operator
def multimux(sel, inputs, output):
n = len(inputs)
i = 0
statements = []
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for osig in output:
choices = [x[i] for x in inputs]
cases = [[Constant(j, sel.bv), osig.eq(choices[j])] for j in range(n)]
cases[n-1][0] = Default()
statements.append(Case(sel, *cases))
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i += 1
return statements
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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:
r.append(v[offset:offset+n])
offset += n
return tuple(r)
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def displacer(signal, shift, output, n=None, reverse=False):
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if n is None:
n = 2**shift.bv.width
w = signal.bv.width
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):
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if n is None:
n = 2**shift.bv.width
w = output.bv.width
cases = []
for i in range(n):
if reverse:
s = n - i - 1
else:
s = i
cases.append([Constant(i, shift.bv), output.eq(signal[s*w:(s+1)*w])])
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cases[n-1][0] = Default()
return Case(shift, *cases)