;====================================================== ;Code that determines whether a command line ;was present or not. Have a look and see how it works ;The program segment prefix (PSP) contains information ;about the program including the number or characters ;in the command tail at 80h and the command tail ;which begins at 81h and is 127 bytes long. ;Compile into a .COM file ;====================================================== .MODEL TINY .8086 .CODE .STARTUP START: xor cx, cx ; cx = 0 mov cl, byte ptr es:[80h] ; Get length of command tail from PSP ; MASM sets ES to point to PSP cmp cl, 0 je nocmln ; There isn't a command line - exit! ; Knows where the end is. mov ah, 9 mov dx, offset Hello int 21h ; Print the string mov ah,4ch int 21h nocmln: mov ah,9 mov dx,offset NOC int 21h mov ah,4ch int 21h Hello db 'Command line detected',0ah,0dh,24h NOC DB 'No command line detected',0ah,0dh,24h END ; Set end of program