;       Matt Wilhelm's Small Starfield

.model tiny

.code
org 100h

start:
        mov     al,13h
        int     10h

        mov     bh,0a0h
hidden_ret:
        mov     es,bx

;        dec     ch             ; for many stars
genstar:
        in      al,40h          ; pop ax works (but sucks)
                                ; inc ax works, and looks nice
                                ; (but loses randomness)
        aaa

scroll:
        sbb     di,ax
        stosb
        loop    genstar

        mov     ah,1            ; keycheck
        int     16h
        jnz     hidden_ret + 1

        xor     ax,ax           ; CBW works on some systems

        xchg    al,es:[di]
        inc     cx

        jmp     scroll          ; jmp to scroll - 1 for a different look
end start