OP_std_modadd
dest = OP_std_modadd(base, offset, cb->desc->size);
return (OP_std_modadd(cb_desc->end, 1, cb_desc->size) == cb_desc->start);
dest = OP_std_modadd(base, offset, cb_desc->size);
cb_desc.start = OP_std_modadd(cb_desc.start, 1, cb_desc.size);
offset = OP_std_modadd(cb_desc.start, offset, cb_desc.size);