MAX_IO_SPACES_BITS   40 arch/ia64/include/asm/io.h #define MAX_IO_SPACES			(1UL << MAX_IO_SPACES_BITS)
MAX_IO_SPACES_BITS   68 arch/ia64/include/asm/io.h #define PIO_OFFSET		(1UL << (MAX_IO_SPACES_BITS + IO_SPACE_BITS))