65 lines
2 KiB
Python
65 lines
2 KiB
Python
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import re
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def twosComplementToDenary(bitPattern):
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value = 0
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for i in range(len(bitPattern) - 1, -1, -1):
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placeValue = 2 ** (len(bitPattern) - i - 1)
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if i == 0: placeValue *= -1
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value += int(bitPattern[i]) * placeValue
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return value
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def twosComplementNormalisedToDenary(bitPattern):
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wholePart, fractionalPart = bitPattern[0], bitPattern[-len(bitPattern)+1:]
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value = -1 if int(wholePart) == 1 else 0
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for i in range(len(fractionalPart), 0, -1):
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placeValue = 2 ** -i
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value += int(fractionalPart[i - 1]) * placeValue
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return value
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while True:
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try:
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binary = input('Please enter the bit pattern you would like to decode: ')
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if re.match('[^01]+', binary):
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raise ValueError
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break
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except ValueError:
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print('Please ensure that you input a valid binary sequence!')
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while True:
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try:
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while True:
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try:
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mantissaBits = int(input('Please enter the amount of bits that the mantissa uses: '))
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break
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except ValueError:
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print('Please ensure that you input a valid integer!')
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while True:
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try:
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exponentBits = int(input('Please enter the amount of bits that the exponent uses: '))
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break
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except ValueError:
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print('Please ensure that you input a valid integer!')
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if exponentBits + mantissaBits != len(binary):
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raise ValueError
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break
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except ValueError:
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print(f'The amount of bits you inputed for the mantissa and exponent do not add up to the length of your sequence - please make sure they span the entire range of the sequence! For reference, your sequence was {binary}')
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binary = str(binary)
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mantissa = binary[:mantissaBits]
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exponent = binary[-exponentBits:]
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denaryExponent = twosComplementToDenary(exponent)
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denaryMantissa = twosComplementNormalisedToDenary(mantissa)
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print(denaryMantissa * (2 ** denaryExponent))
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