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 C16 and Plus/4 IRQ

;
;  setup irq-routine and properly exit to screen-editor
;
;  Fri, 26.Juli 2019
;

!to "irq.prg",cbm
*= $1000
!byte $00,$0c,$10,$0a,$00,$9e,$34,$31,$30,$39,$00,$00,$00
; main
*=$100d
                 lda #<flash_border    ; setup new own irq  
                 sta $0314
                 lda #>flash_border
                 sta $0315
                 cli
                 jmp*  
flash_border:    
-                lda $ff1d             ; wait for rasterline
                 cmp #$ff              
                 bne -       
                 inc $ff19             ; inc bordercolor
                 lda #$7f
                 sta $fd30             ; keyboardscan
                 sta $ff08 
                 lda $ff08
                 cmp #$ef              ; space to end         
                 beq irq_exit  
                 ldy #$80              ; delay 
-                dey
                 bne - 
                 pla                   ; exit to service-routine
                 tay    
                 pla   
                 tax    
                 pla    
                 rti    
 
irq_exit:        sei
                 lda #$0e              ; set nativ address $ce0e
                 sta $0314
                 lda #$ce
                 sta $0315 
                 cli
                 jmp $8003             ; basic warmstart

 

Letzte Änderung: 2019-07-26 20:49:50