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irq.asm
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73 lines (54 loc) · 3.88 KB
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;
; Title: IRQ and Interrupt Handlers
; Author: Dean Belfield
; Created: 20/08/2025
; Last Updated: 22/09/2025
;
; Modinfo:
;
SECTION KERNEL_IRQ
PUBLIC _initIRQs
PUBLIC _VBlank,_Port123b
; ******************************************************************************************************************************
; Main IRQ vector - org'd at $FCFC (as per Spectrum IM2 rules of Lo/Hi need to be the same value)
; ******************************************************************************************************************************
IM2Routine: EI
JP IRQHandler
; $FD00 ($FCFC + 4 bytes)
;
vectorTable: DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine,IM2Routine
DW IM2Routine
; ******************************************************************************************************************************
; Setup IRQ function - 512 bytes left at this point
; ******************************************************************************************************************************
_initIRQs: DI
LD A,vectorTable>>8
LD I,A
IM 2
EI
RET
; ******************************************************************************************************************************
; Main IRQ function - 512 bytes left at this point
; ******************************************************************************************************************************
IRQHandler: PUSH AF
LD A,1
LD (_VBlank),a ; Flag VBlank
POP AF
RETI
; ******************************************************************************************************************************
; IRQ Data
; ******************************************************************************************************************************
_VBlank: DB 0
_Port123b: DB 0
; ******************************************************************************************************************************
; Write this so that we can detect overruns from the IRQ segment
; ******************************************************************************************************************************
SECTION KERNEL_END
ENDIRQ: RET