@x special diagnostic info for cubic_intersection debugging [p23 of BUGMF.ch]
loop@+	begin continue:
@y
loop@+	begin continue:
wlog_cr;
wlog_ln(cur_t:12,cur_tt:12,delx:12,dely:12,tol:12);
wlog_ln(stack_1(x_packet(xy)):13,stack_2(x_packet(xy)):12,stack_3(x_packet(xy)):12,
 stack_min(x_packet(xy)):12,stack_max(x_packet(xy)):12);
wlog_ln(stack_1(y_packet(xy)):13,stack_2(y_packet(xy)):12,stack_3(y_packet(xy)):12,
 stack_min(y_packet(xy)):12,stack_max(y_packet(xy)):12);
wlog_ln(stack_1(u_packet(uv)):13,stack_2(u_packet(uv)):12,stack_3(u_packet(uv)):12,
 stack_min(u_packet(uv)):12,stack_max(u_packet(uv)):12);
wlog_ln(stack_1(v_packet(uv)):13,stack_2(v_packet(uv)):12,stack_3(v_packet(uv)):12,
 stack_min(v_packet(uv)):12,stack_max(v_packet(uv)):12);
@z