io_map
unsigned short io_map[IO_MAP_SIZE];
grub_memset ((char *) io_map, 0, IO_MAP_SIZE * sizeof (unsigned short));
for (port = io_map; *port != 0; port++)
grub_memset ((char *) io_map, 0,
for (port = io_map; *port; port++, addr += sizeof (unsigned short))
extern unsigned short io_map[];