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;
; IRQ handling (Vic20 version)
;
.export initirq, doneirq
.import callirq
.include "vic20.inc"
; ------------------------------------------------------------------------
.segment "ONCE"
initirq:
lda IRQVec
ldx IRQVec+1
sta IRQInd+1
stx IRQInd+2
lda #<IRQStub
ldx #>IRQStub
jmp setvec
; ------------------------------------------------------------------------
.code
doneirq:
lda IRQInd+1
ldx IRQInd+2
setvec: sei
sta IRQVec
stx IRQVec+1
cli
rts
; ------------------------------------------------------------------------
.segment "LOWCODE"
IRQStub:
cld ; Just to be sure
jsr callirq ; Call the functions
jmp IRQInd ; Jump to the saved IRQ vector
; ------------------------------------------------------------------------
.data
IRQInd: jmp $0000
|
