mirror of
https://github.com/cc65/cc65.git
synced 2024-12-26 08:32:00 +00:00
419eb700b5
The way we want to use the INITBSS segment - and especially the fact that it won't have the type bss on all ROM based targets - means that the name INITBSS is misleading. After all INIT is the best name from my perspective as it serves several purposes and therefore needs a rather generic name. Unfortunately this means that the current INIT segment needs to be renamed too. Looking for a short (ideally 4 letter) name I came up with ONCE as it contains all code (and data) accessed only once during initialization.
72 lines
1.5 KiB
ArmAsm
72 lines
1.5 KiB
ArmAsm
;
|
|
; IRQ handling (ATARI version)
|
|
;
|
|
|
|
.export initirq, doneirq
|
|
.import callirq
|
|
|
|
.include "atari.inc"
|
|
.ifdef __ATARIXL__
|
|
.import __CHARGEN_START__
|
|
.include "romswitch.inc"
|
|
.endif
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.segment "ONCE"
|
|
|
|
initirq:
|
|
lda VVBLKD
|
|
ldx VVBLKD+1
|
|
sta IRQInd+1
|
|
stx IRQInd+2
|
|
lda #7
|
|
ldy #<IRQStub
|
|
ldx #>IRQStub
|
|
jmp SETVBV
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.code
|
|
|
|
doneirq:
|
|
lda #7
|
|
ldy IRQInd+1
|
|
ldx IRQInd+2
|
|
jmp SETVBV
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.segment "LOWCODE"
|
|
|
|
IRQStub:
|
|
cld ; Just to be sure
|
|
.ifdef __ATARIXL__
|
|
.ifdef CHARGEN_RELOC
|
|
lda CHBAS
|
|
pha
|
|
.endif
|
|
lda PORTB
|
|
pha
|
|
and #$FE
|
|
sta PORTB ; disable ROM
|
|
set_chbase >__CHARGEN_START__
|
|
.endif
|
|
jsr callirq ; Call the functions
|
|
.ifdef __ATARIXL__
|
|
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
|