name            numlock
        page            58,132
        title           NUMLOCK.COM

;
;
; NUMLOCK.COM   Version 1.00
;
; Copyright (C) Dan Obstbaum 1989
;
;
; Program toggles Num Lock ON.
;
;
; To assemble, link, and convert this program into 
; a .COM file, follow these steps:
;
;
;       C>masm numlock;
;       C>link numlock;
;       C>exe2bin numlock.exe numlock.com
;       C>del numlock.exe
;       C>del numlock.obj
;
;
; Ignore the message "Warning: no stack segment" from the Linker.
;



cseg    segment para    public  'code'


        org     100h            ;.COM


        assume  cs:cseg,ds:cseg,es:cseg,ss:cseg


toggle  proc    near

                                
        push    ds              ;save DS

        mov     ax,40h          ;BIOS data segment
        mov     ds,ax

        mov     bx,[ds:17h]     ;get Shift Status byte

        or      bx,00100000b    ;Num Lock bit to 1

        mov     [ds:17h],bx     ;Num Lock is now toggled ON

        pop     ds              ;restore


        mov     ah,4ch          ;exit back to MS-DOS  
        mov     al,00h          ;with a "return code" of zero
        int     21h             
                                

toggle  endp


cseg    ends


        end     toggle