multiboot_tag_bootdev
((struct multiboot_tag_bootdev *)mbt)->biosdev,
((struct multiboot_tag_bootdev *)mbt)->slice,
((struct multiboot_tag_bootdev *)mbt)->part);
struct multiboot_tag_bootdev *mbt = buf;
mbi_bootdev(struct multiboot_tag_bootdev *mbt)
((struct multiboot_tag_bootdev *)mbt)->biosdev,
((struct multiboot_tag_bootdev *)mbt)->slice,
((struct multiboot_tag_bootdev *)mbt)->part);