ROSE_MODULUS
rose->vr = (rose->vr + 1) % ROSE_MODULUS;
if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
end = (rose->va + sysctl_rose_window_size) % ROSE_MODULUS;
rose->vs = (rose->vs + 1) % ROSE_MODULUS;
rose->va = (rose->va + 1) % ROSE_MODULUS;
vc = (vc + 1) % ROSE_MODULUS;