;KEY DIFFERENTIATION

;CODE BY REINER RICHTER
;(C) COPYRIGHT, NOT

;THIS IS SOME DEMO CODE TO DISTINGUISH
; BETWEEN DIFFERENT KEY COMBINATIONS
; THAT NOTMALLY GIVE THE SAME ASCII
; RESULT.


CHROUT   = $FFD2   ;KERNAL OUTPUT CHAR
GETIN    = $FFE4   ;KERNAL GET CHAR

LSTX     = 197     ;CURRENT KEY PRESSED
SHFLAG   = 653     ;KEYBOARD SHIFT KEY
                     ;1=SHIFT
                     ;2=COMMODORE
                     ;4=CONTROL


         *= $4000


         CLI
         LDX #0
LOOP     LDA INTROTXT,X  ;PRINT INTRO
         BEQ WAITLOOP    ; TEXT SO YOU
         JSR CHROUT      ; KNOW WHAT TO
         INX             ; DO.
         BNE LOOP
WAITLOOP JSR GETIN     ;WAIT UNTIL THE
         CMP #19       ; APPROPRIATE
         BNE WAITLOOP  ; KEY IS PRESSED.
         LDX #0
         LDA SHFLAG    ;CHECK FOR
         AND #4        ; CONTROL KEY.
         BEQ NOCTRL
         LDX #TXTCTRLS-TXTHOME
NOCTRL   LDA TXTHOME,X
         BEQ EXIT        ; TEXT SO YOU
         JSR CHROUT      ; KNOW WHAT TO
         INX             ; DO.
         BNE NOCTRL
EXIT     RTS

INTROTXT .BYTE 147
         .TEXT "PRESS HOME OR "
         .TEXT "CONTROL S..."
         .BYTE 13,0

TXTHOME  .TEXT "HOME WAS PRESSED."
         .BYTE 0

TXTCTRLS .TEXT "CONTROL S WAS PRESSED."
         .BYTE 0