kernel/16bit/gdt.asm

   1 ;----------------------------------------------------------;
   2 ; BOS kernel                Christoffer Bubach, 2004-2005. ;
   3 ;----------------------------------------------------------;
   4 ;                                                          ;
   5 ;     Global Descriptor Table (GDT).                       ;
   6 ;                                                          ;
   7 ;----------------------------------------------------------;
   8
   9 ;-------------------;
  10 ;  pointer to GDT   ;
  11 ;-------------------;
  12 gdtr:
  13     .size        dw   gdt_end - gdt - 1
  14     .address     dd   0x7400                          ; here we move the gdt
  15
  16 ;-----------------------------------;
  17 ;  Global Descriptor Table (GDT).   ;
  18 ;-----------------------------------;
  19 gdt:
  20     .null        dw   0x0000, 0x0000, 0x0000, 0x0000  ; null desc.
  21     .BOS_code:   dw   0xFFFF, 0x0000, 0x9A00, 0x00CF  ; 0x08 , was 9800 before.
  22     .BOS_data:   dw   0xFFFF, 0x0000, 0x9200, 0x00CF  ; 0x10
  23     .BOS_16code: dw   0xFFFF, 0x0000, 0x9A00, 0x0000  ; 0x18
  24     .BOS_16data: dw   0xFFFF, 0x0000, 0x9200, 0x0000  ; 0x20
  25 gdt_end: