Ideal
Model tiny
Dataseg

FirstStart db "First start", 10, 13, '$'
AccessDenied db "Access denied", 10, 13, '$'
AccessGranted db "Access granted", 10, 13, '$'
FirstTime db 0
FirstVsn dw 0, 0
FirstPathLength db 0
FirstPath db 256 dup(0)
Vsn dw 0, 0
Path db 256 dup(0)
PathLength db 0
DiskInfo dw 64 dup(0)


Codeseg
org 100h

proc main
mov ds, [2ch]
mov bx, 0

SEARCH_START:
add bx, 1
mov al, [bx]
cmp al, 0
jne SEARCH_START
mov al, [bx + 1]
cmp al, 1
jne SEARCH_START

add bx, 2
mov di, -1
lea bp, cs:Path

SAVE:
add bx, 1
add di, 1
mov al, [bx]
mov [bp +di], al
cmp al, 0
jne SAVE
mov ax, di
mov cs:PathLength, al
push cs
pop ds

mov ax, 6900h
xor bl, bl
lea dx, DiskInfo
int 21h

mov ax, DiskInfo + 2
mov Vsn, ax
mov ax, DiskInfo + 4
mov Vsn + 2, ax

cmp FirstTime, 0
jne NOTFIRST


mov ax, 3d00h
lea dx, Path
int 21h
mov bx, ax

mov ax, 4301h
mov cx, 0
int 21h

mov ah, 3eh
int 21h

mov ax, 3d02h
int 21h
mov bx, ax

mov dx, 12dh
mov ax, 4201h
int 21h

mov FirstTime, 1

mov ah, 40h
mov cx, 1
lea dx, FirstTime
int 21h

mov ah, 40h
mov cx, 4
lea dx, Vsn
int 21h

mov ah, 40h
mov cx, 1
lea dx, PathLength
int 21h

xor cx, cx
mov cl, PathLength
mov ah, 40h
lea dx, Path
int 21h

mov ah, 3Eh
int 21h

mov ah, 9
lea dx, FirstStart
int 21h

jmp KONEC

NOTFIRST:

mov ax, Vsn
cmp ax, FirstVsn
jne NOACCESS
mov ax, Vsn + 2
cmp ax, FirstVsn + 2
jne NOACCESS

mov al, PathLength
cmp al, FirstPathLength
jne NOACCESS

mov cl, PathLength
xor di, di

COMPARE:
mov al, FirstPath + di
cmp al, Path + di
jne NOACCESS
inc di
loop COMPARE

mov ah, 9
lea dx, AccessGranted
int 21h

jmp KONEC

NOACCESS:

mov ah, 9
lea dx, AccessDenied
int 21h

KONEC:
mov ah, 1
int 21h

mov ah, 4ch
int 21h
endp main
end main