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