seqLessWrap

compare_less_wrap(lhs, rhs, ACK_MASK) from utp_stream.cpp: true iff lhs is "less than" rhs in 16-bit sequence space, treating the shorter walking direction as the ordering. The exact C++ logic:

dist_down = (lhs - rhs) & mask;
dist_up   = (rhs - lhs) & mask;
return dist_up < dist_down;