#ifndef _HEAD_H #define _HEAD_H typedef struct desc_struct { unsigned long a,b; } desc_table[256]; extern unsigned long pg_dir[1024]; extern desc_table idt,gdt; #define GDT_NUL 0 #define GDT_CODE 1 #define GDT_DATA 2 #define GDT_TMP 3 #define LDT_NUL 0 #define LDT_CODE 1 #define LDT_DATA 2 #endif