;Screen Control Assembly Lanuage Routines for C02
;Skeleton Code for Systems with no Screen Control

        SUBROUTINE _SCREEN

SMTEXT  EQU $00     ;Default Text Screen
SMWIDE  EQU $FF     ;Wide Text Screen (Undefined)

;Set Screen Mode
SETSCR: CMP #SMTEXT ;If Not Default Text
        BNE GETPOS  ;Return Error
                    ;Else Return 0
;Get Screen Mode
GETSCR: LDA #0      ;Return 0 (Default Text Mode)
        RTS

;Clear the Screen
CLRSCR: RTS         ;No Action

;Move Cursor Home
CRSRHM  EQU CLRSCR  ;No Action

;Move Cursor to Specified Coordinates
SETPOS  EQU CLRSCR  ;No Action 
 
;Get Cursor Position
GETPOS: LDA #$FF    ;Return Error 
        TAY
        RTS

;Get Screen Size
GETSIZ  LDA #80     ;Return 80x25
        LDY #25
        RTS

