49 lines
1.6 KiB
Python
49 lines
1.6 KiB
Python
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#!/usr/bin/env python3
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# For each error-correction level (0, 1, or 2-bit errors)
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# generate the set of possible DF values that could possibly be
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# corrected to DF11/17/18/19 messages, expressed as a bitset.
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def popcount(x):
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return bin(x).count('1')
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# is the Hamming distance between 'df' and a valid long-message DF no more than `max_errors`?
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def correctable_long(df, max_errors):
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if popcount(df ^ 17) <= max_errors: return True
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if popcount(df ^ 18) <= max_errors: return True
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#if popcount(df ^ 19) <= max_errors: return True
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return False
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# is the Hamming distance between 'df' and a valid short-message DF no more than `max_errors`?
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def correctable_short(df, max_errors):
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if popcount(df ^ 11) <= max_errors: return True
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return False
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# Generate a bitset value where bit N is set if predicate(N) is True
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def bitset(predicate):
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result = 0
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for i in range(32):
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if predicate(i):
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result |= 1 << i
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return result
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shorts = [
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bitset(lambda x: correctable_short(x,0)),
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bitset(lambda x: correctable_short(x,1)),
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bitset(lambda x: correctable_short(x,1)) # deliberately not 2
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]
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longs = [
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bitset(lambda x: correctable_long(x,0)),
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bitset(lambda x: correctable_long(x,1)),
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bitset(lambda x: correctable_long(x,2))
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]
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print('static const uint32_t df_correctable_short[MODES_MAX_BITERRORS + 1] = {')
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print(' ' + ', '.join(f'0x{i:08x}' for i in shorts))
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print('};')
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print('static const uint32_t df_correctable_long[MODES_MAX_BITERRORS + 1] = {')
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print(' ' + ', '.join(f'0x{i:08x}' for i in longs))
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print('};')
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