git.sur5r.net Git - cc65/blob - libsrc/creativision/irq.s

   1 ;
   2 ; IRQ handling (CreatiVision version)
   3 ;
   4
   5         .export         initirq, doneirq
   6         .import         callirq, irq2
   7
   8         .include        "creativision.inc"
   9
  10 ; ------------------------------------------------------------------------
  11
  12 .segment        "ONCE"
  13
  14 initirq:
  15         lda     #<IRQStub
  16         ldx     #>IRQStub
  17         jmp     setvec
  18
  19 ; ------------------------------------------------------------------------
  20
  21 .code
  22
  23 doneirq:
  24         lda     #<BIOS_IRQ2_ADDR
  25         ldx     #>BIOS_IRQ2_ADDR
  26 setvec: sei
  27         sta     irq2+1
  28         stx     irq2+2
  29         cli
  30         rts
  31
  32 ; ------------------------------------------------------------------------
  33
  34 .segment        "CODE"
  35
  36 IRQStub:
  37         cld                             ; Just to be sure
  38         jsr     callirq                 ; Call the functions
  39         jmp     BIOS_IRQ2_ADDR          ; Jump to the BIOS IRQ vector
  40