[bits 16]
[org 0x7c00]

                   ; Use the boot drive number passed to us by BIOS in register DL
start:
    xor ax,ax      ; We want a segment of 0 for DS for this question
    mov ds,ax      ;     Set AX to appropriate segment value for your situation
    mov es,ax      ; In this case we'll default to ES=DS
    mov bx,0x8000  ; Stack segment can be any usable memory

    mov ss,bx      ; This places it with the top of the stack @ 0x80000.
    mov sp,ax      ; Set SP=0 so the bottom of stack will be @ 0x8FFFF

    cld            ; Set the direction flag to be positive direction

    mov si, wolf_wel_msg
    call wolf_print

    mov si, wolf_kernel_load
    call wolf_print

    pushf
    stc

    mov ah,00
    int 13h

    read_sector:
        mov ax, 0x0
        mov es, ax      ; ES = 0
        mov bx, 0x1000  ; BX = 0x1000. ES:BX=0x0:0x1000 
                        ; ES:BX = starting address to read sector(s) into
        mov ah, 02      ; Int 13h/AH=2 = Read Sectors From Drive
        mov al, 01      ; Sectors to read = 1
        mov ch, 00      ; CH=Cylinder. Second sector of disk
                        ; is at Cylinder 0 not 1
        mov cl, 02      ; Sector to read = 2
        mov dh, 00      ; Head to read = 0
                        ; DL hasn't been destroyed by our bootloader code and still
                        ;     contains boot drive # passed to our bootloader by the BIOS
        int 13h

    jc wolf_error
    popf
    jmp 0x0:0x1000
    cli
    hlt

    wolf_error:
        mov si, wolf_error_msg
        call wolf_print
        mov si, wolf_error_msg1
        call wolf_print
        mov ah,00
        int 16h
        xor ax,ax
        int 19h

    wolf_print:
        lodsb
        or al,al
        jz exit
        mov ah,0x0e
        int 10h
        jmp wolf_print
        exit:
        ret

; Moved the data before the boot signature but after the code
wolf_wel_msg db 'Welcome to this publication...',0x0D,0x0A,0
wolf_kernel_load db 'Loading program',0x0D,0x0A,0
wolf_error_msg db 'Program not found!',0x0D,0x0A,0
wolf_error_msg1 db 'Press any key to restart..',0

times 510-($-$$) db 0
dw 0xAA55