| 0,0 → 1,74 |
|---|
| format MZ |
| heap 0 |
| stack 800h |
| entry main:start |
| |
| segment main use16 |
| |
| use16 |
| start: |
| |
| mov ax,_data |
| mov ds, ax |
| mov es, ax |
| |
| xor eax, eax |
| mov ax,ds |
| |
| shl eax, 4 |
| |
| mov bx, gdt |
| add ebx, eax ; ebx - ëèíåéíûé àäðåñ gdt |
| |
| mov word [gdtPtr], 2 * 8 -1 ; ïðåäåë gdt 2 äåñêðèïòîðà = 0x000f |
| mov dword [gdtPtr + 2], ebx |
| |
| lgdt pword [gdtPtr] |
| |
| in al, 0x70 ;çàïðåùàåì NMI |
| mov bl, al |
| or al, 0x80 |
| out 70h , al |
| in al, 0x71 ;íåêîòîðûå RTC ïîñëå çàïèñè áàéòà â ïîðò 0õ70 |
| ;îæèäàþò îáðàùåíèÿ ê ïîðòó 0x71 |
| |
| cli |
| |
| mov eax, cr0 |
| or al, 01b |
| mov cr0, eax |
| |
| mov dx, 0x08 |
| mov gs, dx ;gs - ãëîáàëüíûé ñåãìåíò ñ áàçîé 0 è ïðåäåëîì 0xFFFFFFFF |
| mov fs, dx |
| |
| and al, 0xFE |
| mov cr0, eax |
| |
| sti |
| |
| mov al, bl |
| out 70h , al |
| in al, 71h |
| |
| mov dx,92h |
| in al,dx |
| or al,2 |
| out dx,al |
| |
| ;òåïåðü ìîæíî ïîëó÷èòü äîñòóï êî âñåé ïàìÿòè |
| ;íàïðèìåð |
| ;mov eax, [gs:0xFFFFFFF0] ; |
| |
| mov ah,4ch ;çàâåðøåíèå ÄÎÑ ïðîãðàììû |
| int 21h |
| |
| segment _data use16 |
| |
| align 16 |
| |
| gdt dw 0, 0, 0, 0 ;0 |
| _flat dw 0ffffh,0,0F200h,008fh ;08 ñåãìåíò äàííûõ DPL = 3 |
| ;áàçà 0, ïðåäåë 0xFFFFFFFF |
| |
| gdtPtr dq ? |