Just for the record, there's a less-branchy analog of the floor division code I suggested for modulo. In Python-land, it looks like this: def propermod(a, b): # mimic the C setup assert a != 0 and b != 0 left = abs(a) size_a = -1 if a < 0 else 1 right = abs(b) size_b = -1 if b < 0 else 1 # Compute mod: only one branch needed. mod = left % right if size_a == size_b else right - 1 - (left - 1) % right return mod * size_b # Verify that we get the same results as the regular mod. for n in range(-100, 100): if n == 0: continue for d in range(-100, 100): if d == 0: continue assert propermod(n, d) == n % d It may well not have any significant effect here, though.