1 #ifndef _LINUX_HEAD_H
   2 #define _LINUX_HEAD_H
   3 
   4 typedef struct desc_struct {
   5         unsigned long a,b;
   6 } desc_table[256];
   7 
   8 extern unsigned long swapper_pg_dir[1024];
   9 extern desc_table idt,gdt;
  10 
  11 #define GDT_NUL 0
  12 #define GDT_CODE 1
  13 #define GDT_DATA 2
  14 #define GDT_TMP 3
  15 
  16 #define LDT_NUL 0
  17 #define LDT_CODE 1
  18 #define LDT_DATA 2
  19 
  20 #endif