#define RAMDISK_PROMPT_FLAG (0x8000)
#define RAMDISK_LOAD_FLAG (0x4000)
+#define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
+#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
+#define PFN_PHYS(x) ((x) << PAGE_SHIFT)
+
extern unsigned long memory_start;
extern unsigned long memory_end;