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corelogic: support reverse in displacer/chooser

This commit is contained in:
Sebastien Bourdeauducq 2012-02-13 23:10:27 +01:00
parent 264be80f2d
commit 1662e1b3bc
1 changed files with 14 additions and 4 deletions
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18
migen/corelogic/misc.py
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@ -40,17 +40,27 @@ def split(v, *counts):
offset += n
return tuple(r)
def displacer(signal, shift, output, n=None):
def displacer(signal, shift, output, n=None, reverse=False):
if n is None:
n = 2**shift.bv.width
w = signal.bv.width
l = [Replicate(shift == i, w) & signal for i in range(n)]
if reverse:
r = reversed(range(n))
else:
r = range(n)
l = [Replicate(shift == i, w) & signal for i in r]
return output.eq(Cat(*l))
def chooser(signal, shift, output, n=None):
def chooser(signal, shift, output, n=None, reverse=False):
if n is None:
n = 2**shift.bv.width
w = output.bv.width
cases = [[Constant(i, shift.bv), output.eq(signal[i*w:(i+1)*w])] for i in range(n)]
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])])
cases[n-1][0] = Default()
return Case(shift, *cases)