| # bits = 8, int2bits(i) = bits0 + bits, # bits1 = 8, int2bits(j) = bits2 + bits1 ⊦ bits0 = [], bits2 = [], bits = [], bits2 + bits1 = [], lastn(8, fillsgn(8, bitsand(bits0, bits2) + bitsand(bits, bits1))) = lastn(8, fillsgn(8, bitsand(bits2 + bits1, bits))) |
⊦ n ≤ # bits → fillsgn(n, bits) = bits
¬ 8 ≤ #(bitsand(bits0, bits2) + bitsand(bits, bits1)), # bits = 8, int2bits(i) = bits0 + bits, # bits1 = 8, int2bits(j) = bits2 + bits1 ⊦ bits0 = [], bits2 = [], bits = [], bits2 + bits1 = [], lastn(8, fillsgn(8, bitsand(bits0, bits2) + bitsand(bits, bits1))) = lastn(8, fillsgn(8, bitsand(bits2 + bits1, bits)))
8 ≤ #(bitsand(bits0, bits2) + bitsand(bits, bits1)), # bits = 8, int2bits(i) = bits0 + bits, # bits1 = 8, int2bits(j) = bits2 + bits1 ⊦ bits0 = [], bits2 = [], bits = [], bits2 + bits1 = [], lastn(8, bitsand(bits0, bits2) + bitsand(bits, bits1)) = lastn(8, fillsgn(8, bitsand(bits2 + bits1, bits)))
Used terms: bitsand(bits0, bits2) + bitsand(bits, bits1), 8