major_version	    equ     4	    ;Major DOS version
minor_version	    equ     00	    ;Minor DOS Version

MINOR_VERSION equ minor_version	; NASM port equate
MAJOR_VERSION equ major_version	; NASM port equate
expected_version    equ     (MINOR_VERSION << 8)+MAJOR_VERSION

alt_major_version    equ     5	    ;Major DOS version
alt_minor_version    equ     26	    ;Minor DOS Version

alt_expected_version    equ     (alt_minor_version << 8) + alt_major_version

new_major_version    equ     5	    ;Major DOS version
new_minor_version    equ     38	    ;Minor DOS Version
new_expected_version    equ     (new_minor_version << 8) + new_major_version

       %warning out: ... for DOS Version 4.00 ...

       ;******************************
       ;Each assembler program should:
       ;  mov ah,030h			;DOS Get Version function
       ;  int 021h			;Version ret. in AX,minor version first
       ;  cmp ax,expected_version	;ALL utilities should check for an
       ;  jne error_handler		; EXACT version match.
       ;******************************