1
0
mirror of https://github.com/cc65/cc65.git synced 2024-11-13 13:11:06 +00:00
cc65/libsrc/atari/irq.s

72 lines
1.5 KiB
ArmAsm
Raw Normal View History

;
; IRQ handling (ATARI version)
;
.export initirq, doneirq
.import callirq
.include "atari.inc"
2013-09-20 16:09:53 +00:00
.ifdef __ATARIXL__
.import __CHARGEN_START__
.include "romswitch.inc"
.endif
; ------------------------------------------------------------------------
.segment "INIT"
initirq:
lda VVBLKD
ldx VVBLKD+1
sta IRQInd+1
stx IRQInd+2
lda #7
ldy #<IRQStub
ldx #>IRQStub
2014-05-26 23:49:35 +00:00
jmp SETVBV
; ------------------------------------------------------------------------
.code
doneirq:
lda #7
ldy IRQInd+1
ldx IRQInd+2
2014-05-26 23:49:35 +00:00
jmp SETVBV
; ------------------------------------------------------------------------
.segment "LOWCODE"
IRQStub:
cld ; Just to be sure
.ifdef __ATARIXL__
2013-09-20 16:09:53 +00:00
.ifdef CHARGEN_RELOC
lda CHBAS
pha
.endif
lda PORTB
pha
2013-10-01 09:32:08 +00:00
and #$FE
2013-09-20 16:09:53 +00:00
sta PORTB ; disable ROM
set_chbase >__CHARGEN_START__
.endif
jsr callirq ; Call the functions
.ifdef __ATARIXL__
2013-09-20 16:09:53 +00:00
pla
sta PORTB ; restore old ROM setting
.ifdef CHARGEN_RELOC
pla
sta CHBAS
sta CHBASE
.endif
.endif
jmp IRQInd ; Jump to the saved IRQ vector
; ------------------------------------------------------------------------
.data
IRQInd: jmp $0000