N ; GETKEY2.SCR		DEBUG Assembly Language script
N ;
N ; "2nd Generation" Programming Language demo for CIS 120
N ;
N ; Mike Huffman, Portland Community College
N ; Computer Information Systems, Winter Term, 2001
N ;
N ; Last update: 10 FEB 2001
N ;
A 100
MOV     AH,00	; BIOS service 00H Read Keyboard Character
INT     16	; call BIOS
CMP     AL,61	; is char less than 'a'?
JB      010E	; yes, display the char
CMP     AL,7A	; is char greater than 'z'?
JA      010E	; yes, display the char
AND     AL,DF	; char is a-z, clear bit 5 to convert to upper case
		; display the char; in a "real" program the char
		; would be used to, say, check for a menu choice
MOV     DL,AL	; DL = char to display
MOV     AH,02	; DOS service 02H Display output
INT     21	; call DOS
CMP     AL,51	; was char 'Q' (Quit)?
JNE     0100	; no, loop and get another character
MOV     AL,00   ; yes, AL = return code
MOV     AH,4C   ; AH = DOS service 4CH Terminate with return code
INT     21	; call DOS
		; leave blank line to end DEBUG Assembly mode
			
N getkey2.com
R CX
1E
W
Q