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29 lines
813 B
Python
29 lines
813 B
Python
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#!/usr/bin/python
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print "Period,nbits,feedback,mask"
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for n in range(1,18):
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mask = (1<<n)-1
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hibit = (1<<(n-1))
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for i in range(0,1<<n):
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for invert in [0,1]:
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x = 1
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seq = []
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seen = set()
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while x and not x in seen:
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seq.append(x)
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seen.add(x)
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feedback = x & hibit
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x = ((x << 1) & mask)
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if invert:
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if not feedback:
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x ^= i
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else:
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if feedback:
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x ^= i
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if x:
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seqindex = seq.index(x)
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seqlen = len(seq) - seqindex
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if seqlen>1:
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print seqlen, "#(%d,%d'%s,%d)" % (n,n,bin(i)[1:],invert), seqindex
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