B_DEVMAGIC
if ((bootdev & B_MAGICMASK) == (u_int)B_DEVMAGIC) {
if ((dev & B_MAGICMASK) == B_DEVMAGIC) { /* search by bootdev */
if ((bootdev & B_MAGICMASK) == (u_int)B_DEVMAGIC) {
if ((dev & B_MAGICMASK) == B_DEVMAGIC) { /* search by bootdev */
if ((bootdev & B_MAGICMASK) == B_DEVMAGIC) {
((partition) << B_PARTITIONSHIFT) | B_DEVMAGIC)