82 lines
2.7 KiB
Python
Executable File
82 lines
2.7 KiB
Python
Executable File
#!/usr/bin/env python3
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with open('input.txt') as f:
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input_string = f.read().split('\n')
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def twos_comp(num, length):
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if num == 0:
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return 0
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num ^= ((1 << length) - 1)
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return num + 1
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def logical_shiftr(num, length, times):
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for t in range(times):
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num = (num >> 1) | ((1 << length) & num)
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return num
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def convert_if_twoscomp(num, length):
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if num & (1 << length - 1):
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return (-1 * twos_comp(num, length))
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return num & (1 << length) - 1
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def debug(multiplicand_b, multiplier_b, length):
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sign = 0
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multiplicand = convert_if_twoscomp(multiplicand_b, length)
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multiplier = convert_if_twoscomp(multiplier_b, length)
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result = multiplicand * multiplier
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result_bin = (twos_comp(result, length * 2), result) [result > 0]
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print("expected result:\t{}\t*\t{}\t=\t{}\t=\t{}".format(multiplicand, multiplier, bin(result_bin), multiplicand * multiplier))
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#print("booths result:\t\t{}\t*\t{}\t=\t{}".format(bin(multiplicand), bin(multiplier), bin(result_booth)))
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def booth(multiplier, multiplicand, length):
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multiplicand_twos_comp = twos_comp(multiplicand, length)
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result = multiplier << 1 # extended bit
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for i in range(length):
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op = result & 0b11
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if op == 0b01:
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result += multiplicand << (length + 1)
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if op == 0b10:
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result += multiplicand_twos_comp << (length + 1)
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result &= (1 << (length * 2) + 1) - 1 # get rid of any overflows
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result = logical_shiftr(result, length * 2, 1)
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result = result >> 1
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return result
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def booth_mod(multiplier, multiplicand, length):
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multiplicand_twos_comp = twos_comp(multiplicand, length)
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result = multiplier << 1 # extended bit
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for i in range(int(length / 2)):
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match result & 0b111:
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case 0b010 | 0b001: # add
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result += multiplicand << (length + 1)
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case 0b011: # add * 2
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result += multiplicand << (length + 2) # extra shift is multiplying multiplicand by 2
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case 0b100: # sub * 2
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result += multiplicand_twos_comp << (length + 2)
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case 0b101 | 0b110: # sub
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result += multiplicand_twos_comp << (length + 1)
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result &= (1 << (length * 2) + 1) - 1 # get rid of any overflows
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result = logical_shiftr(result, length * 2, 2)
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result = result >> 1
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return result
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for operation in input_string:
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if operation == '' or operation[0] == '#':
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continue
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length = len(operation.split(" ")[0])
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multiplicand = int(operation.split(" ")[0], 2)
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multiplier = int(operation.split(" ")[1], 2)
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debug(multiplicand, multiplier, length)
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result_booth = booth(multiplier, multiplicand, length)
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result_mod_booth = booth_mod(multiplier, multiplicand, length)
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print("booths:\t\t\t", bin(result_booth))
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print("modified booths:\t", bin(result_mod_booth))
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