.model  small
             .code

start        segment
             assume  cs:start,ds:start
             org     0

ghost        proc    far
header       dd      0ffffffffh
attributes   dw      2000h
pointers     dw      offset strategy,offset commands
blockdev     db      0,0,2,2,1,0,1,40h,0,64h,0,0fah,1,0,8,0,1,0,0,0
ghost        endp

strategy     proc    far
             mov     cs:data1,bx
             mov     cs:data2,es
             retf
strategy     endp

commands     proc    far
             push    si
             push    ds
             lds     si,dword ptr cs:data1
             mov     word ptr [si+3],8102h
             cmp     byte ptr [si+2],0
             jne     loc1
             call    first
loc1:        pop     ds
             pop     si
             retf
commands     endp
             
data1        dw      0
data2        dw      0
             dw      24 dup(000bh)
par          db      0
data3        db      0

first        proc    near
             pushf
             push    ax
             push    bx
             push    cx
             push    dx
             push    si
             push    di
             push    ds
             push    es
             cld
             push    cs
             pop     ds
             mov     dx,offset message
             mov     ah,9
             int     21h
             call    second
             jc      loc2
             call    third
             jnc     loc3
loc2:        mov     al,0
             jmp     short loc4
loc3:        mov     al,data3
             sub     al,par
             cmp     al,1
             jge     loc4
             mov     al,0
loc4:        lds     bx,dword ptr data1
             mov     cs:blockdev,al
             mov     [bx+0dh],al
             xor     ah,ah
             cmp     al,0
             je      loc5
             shl     ax,1
             add     ax,45h
loc5:        mov     [bx+0eh],ax
             mov     [bx+10h],cs
             mov     word ptr [bx+12h],45h
             mov     [bx+14h],cs
             mov     word ptr [bx+3],100h
             pop     es
             pop     ds
             pop     di
             pop     si
             pop     dx
             pop     cx
             pop     bx
             pop     ax
             popf
             retn
first        endp

second       proc    near
             mov     al,24h
             mov     par,al
             mov     ax,4452h
             stc
             int     21h
             jc      loc6
             cmp     ax,dx
             jne     loc6
             cmp     ah,10h
             jne     loc6
             cmp     al,67h
             jne     loc6
             les     si,dword ptr data1
             mov     al,es:[si+16h]
             add     al,40h
             mov     par,al
             jmp     short loc7
loc6:        les     si,dword ptr data1
             cmp     byte ptr es:[si],16h
             jbe     loc7
             les     si,dword ptr data1
             mov     al,es:[si+16h]
             add     al,40h
             mov     par,al
loc7:        cmp     par,43h
             jb      loc8
             cmp     par,5ah
             jb      loc12
loc8:        les     si,header
             mov     al,40h
loc9:        cmp     si,0ffffh
             je      loc11
             test    word ptr es:[si+4],8000h
             jnz     loc10
             add     al,es:[si+0ah]
loc10:       les     si,dword ptr es:[si]
             jmp     short loc9
loc11:       mov     par,al
loc12:       clc
             retn
second       endp

third        proc    near
             push    ds
             les     bx,dword ptr data1
             lds     si,dword ptr es:[bx+12h]
loc13:       lodsb
             cmp     al,9
             je      loc14
             cmp     al,20h
             je      loc14
             ja      loc13
             jmp     short loc17
loc14:       call    fourth
             cmp     al,20h
             jb      loc17
             and     al,0dfh
             cmp     al,40h
             jb      loc16
             cmp     al,5ah
             ja      loc16
             cmp     byte ptr [si],3ah
             jne     loc15
             inc     si
loc15:       mov     cs:data3,al
             jmp     short loc14
loc16:       mov     dx,18dh
             stc
             pop     ds
             retn
loc17:       clc
             pop     ds
             retn
third        endp

fourth       proc    near
loc18:       lodsb
             cmp     al,20h
             je      loc18
             cmp     al,9
             je      loc18
             retn
fourth       endp

message      db      'Ghost Device Driver vers. 1.00 by Peter2000',13,10,36
             
start        ends

             end