Task 1

        org 100h
        use16

Start:
        push    char
        push    string

        call    SearchChar

        ; AX contains number of symbol (from 1)
        ; if 0 then symbol not founded

        ret

SearchChar:
        push    BP
        mov     BP, SP

        mov     BX, [BP + 6]
        mov     AL, byte[BX]

        mov     BX, [BP + 4]

        mov     DI, -1
Cycle:
        inc     DI

        cmp     byte[BX + DI], 0
        je      NotFound

        cmp     AL, byte[BX + DI]
        jne     Cycle

        inc     DI
        jmp     ProcEnd

NotFound:
        mov     DI, 0

ProcEnd:
        mov     AX, DI

        pop     BP
        ret     4

string  db      'abracadbr', 0
char    db      'd'