| b2i(by1) / i ≤ abs(b2i(by1)), 0 ≤ abs(b2i(by1)) + b2i(by1) / i ⊦ i = ~1, i = 0, b2i(by1) / i = b2i(i2b(b2i(by1) / i)), ¬ b2i(by1) / i < ~128 ∧ ¬ 127 < b2i(by1) / i |
b2i(by1) / i ≤ abs(b2i(by1)), 0 ≤ abs(b2i(by1)) + b2i(by1) / i ⊦ ¬ b2i(by1) / i < ~128, i = ~1, i = 0, b2i(by1) / i = b2i(i2b(b2i(by1) / i))
b2i(by1) / i ≤ abs(b2i(by1)), 0 ≤ abs(b2i(by1)) + b2i(by1) / i ⊦ ¬ 127 < b2i(by1) / i, i = ~1, i = 0, b2i(by1) / i = b2i(i2b(b2i(by1) / i))