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Resetting IRQs
Posted: Mon Feb 05, 2024 1:39 pm
by heaven6502
hmmm..
Me toying again with the VIC20 and for days I try to reset my double IRQ for stable rasters routines... and all I do stops my trackloader at some point...
so simple question... i have a part which has set 2 VIAs timers and i simply want to "switch it back" to normal mode... where I have a simple VBL based IRQ running through $314/15...
i saved all regs prior setting the IRQinit routines and the IRQserver to handle the raster-IRQ and vblank... when I call $fdf9 in ROM to init i/o my trackloader seems fucked up...
Code: Select all
;**************************************************************************
;*
;* IRQ Interrupt server
;*
;******
IRQServer:
lda $912d
asl
asl
bcs irq_skp1
asl
bcc irq_ex1
jsr T2Timeout ;raster IRQ
jmp irq_ex1
irq_skp1:
jsr T1Timeout ;VBL
irq_ex1:
pla
tay
pla
tax
pla
rti
;**************************************************************************
;*
;* Routines + stuff
;*
;******
T1Timeout:
lda #[75+[<t1_TComp]]&255
sec
sbc $9124 ;68-73 (for PAL)
sta t1_SelfModJMP+1
t1_SelfModJMP:
jmp t1_TComp
; START_SAMEPAGE "T1COMP"
t1_TComp:
.byte $a9,$a9,$a9,$a9,$a9,$a9
.byte $a9,$a9,$a9,$a9,$24,$ea
; END_SAMEPAGE
lda InterruptTab
sta $9128
lda InterruptTab+1
sta $9129 ;load T2
lda #$00
sta Line
jsr Update
jsr VertBlanking
.IF DEBUG2
lda t1_SelfModJMP+1
sec
sbc #<t1_TComp
tax
lda #$01
sta $5100,x
.ENDIF ;DEBUG2
rts
T2Timeout:
lda #[$c0+[<t2_TComp]]&255
sec
sbc $9128 ;$ba-$bd (for PAL)
sta t2_SelfModJMP+1
t2_SelfModJMP:
jmp t2_TComp
; START_SAMEPAGE "T2COMP"
; .align $100
t2_TComp:
.byte $a9,$a9,$a9,$a9,$a9,$a9
.byte $a9,$a9,$a9,$a9,$24,$ea
; END_SAMEPAGE
lda TimeLow
sta $9128
lda TimeHigh
sta $9129
SelfModJSR:
jsr SelfModJSR
.IF DEBUG2
lda t2_SelfModJMP+1
sec
sbc #<t2_TComp
tax
lda #$01
sta $5000,x
.ENDIF ;DEBUG2
Update:
lda Line
inc Line
asl
asl
tax
lda InterruptTab+4,x
sta TimeLow
lda InterruptTab+5,x
sta TimeHigh
lda InterruptTab+2,x
sta SelfModJSR+1
lda InterruptTab+3,x
sta SelfModJSR+2
rts ;$2095
TimeLow:
.byte 0
TimeHigh:
.byte 0
Line:
.byte 0
InterruptTab: ;$2099 $13 $54
.word ROWTIME*70-COMPTIME,Rast0
.word -1,-1
PS: revision anyone?
Re: Resetting IRQs
Posted: Mon Feb 05, 2024 1:40 pm
by heaven6502
Code: Select all
.align $100
InterruptInit:
;save the registers
ldx #31
@
lda $9110,x
sta $b9e0,x
dex
bpl @-
; IF RESTOREDISABLE
lda #%00000010
sta $911e ;No RestoreKey
sta $911d
; ENDIF
lda #$7f
sta $912e
sta $912d
lda #%11100000
sta $912e
lda #%01000000
sta $912b
lda #<IRQServer
sta $0314
lda #>IRQServer
sta $0315
jsr Stab ;Find Fixpoint!!! (VertBlank)
lda #<SCREENTIME
sta $9124
lda #>SCREENTIME
sta $9125 ;load T1
rts
Re: Resetting IRQs
Posted: Mon Feb 05, 2024 1:41 pm
by heaven6502
i used those routines back 2018 in Gnork! demo and never run into that issue that it fcks up the trackloader...
Re: Resetting IRQs
Posted: Mon Feb 05, 2024 4:30 pm
by Mike
heaven6502 wrote:Code: Select all
;save the registers
ldx #31
@
lda $9110,x
sta $b9e0,x
dex
bpl @-
That idiom isn't all that helpful to restore the state of the VIAs later - some of the registers (most notably the IER!) react differently to writes than to reads.
Instead I'd simply do a
SEI, then clear both IERs with
LDA #$7F:STA $911E:STA $912E and finally call
JSR $FDF9 in the KERNAL. That routine then (re-)inits the VIAs to a known good state.
PS: revision anyone?
Look
here and leave a short comment in that thread.
Re: Resetting IRQs
Posted: Tue Feb 06, 2024 3:09 am
by heaven6502
Tried that but when I call the rom routine the starting of next part was stopping. So could be something different there after the trackloader. Those 2 IRQs are not used for IO? As Atari guy the sound chip is envolved into IO that's why I am asking dumb questions.
Re: Resetting IRQs
Posted: Tue Feb 06, 2024 3:47 am
by Mike
heaven6502 wrote:Those 2 IRQs are not used for IO?
The two VIA #2 timers control the timing of either the KERNAL IRQ (keyboard, jiffy clock, tape motor control) or the timing of tape load (T1 only) and save (T1 and T2). The VIA #1 timers produce NMIs (mostly for RS232 operations).
It is somewhat possible to run standard IEC I/O alongside VIA#2 T1 IRQs, however as the KERNAL does block IRQs at certain time-critical points, the interrupt routine will be disturbed.
Some time ago I wrote a demonstrator that used both VIA#1 T1 and T2 to do multiple 'raster' IRQs per frame (T1 for sync, T2 for the actual work) - I need to check (in VICE) whether T2 might collide with IEC I/O.
As Atari guy the sound chip is envolved into IO that's why I am asking dumb questions.
There are no dumb questions ...
The VIC chip does the sound, there's no I/O involved here. Maybe you overwrote some vital data in OS workspace?
Re: Resetting IRQs
Posted: Tue Feb 06, 2024 3:54 am
by heaven6502
Now as you mention OS space
I am used to no OS in the way as switched off on C64/Atari800 anyway
.
But good point to check.
Is there a vice version which has a history in debugger to have more clue?
Re: Resetting IRQs
Posted: Tue Feb 06, 2024 8:58 am
by groepaz
use "chis" in the monitor. its enabled by default in any half recent build
Re: Resetting IRQs
Posted: Wed Feb 07, 2024 2:40 pm
by heaven6502
ok... i kicked out everything from the loader part which has IRQ influence.
Code: Select all
lda #10
jsr vsync
sei
lda #$7f
sta $911e
sta $912e
jsr $fdf9 ;reset i/o ;seems this is necessary --> $314/$315 is default
lda #<22150
sta $9124
lda #>22150
sta $9125
lda #<$0114
sta $314
lda #>$0114
sta $315
cli
lda #<$5a00 ;startadress
sta $0112
lda #>$5a00
sta $0113
jmp $100 ;load next part
then I did the above code... at $0114 is music player jsr $xxxx and the jump to the rom routine to $eb15.
the music plays still at normal speed but the track loader stops to load next part....I have no clue now... the head moves to track 18 which is the directory and remains...
Re: Resetting IRQs
Posted: Wed Feb 07, 2024 2:41 pm
by heaven6502
CHIS shows in monitor
loop BIT $911f
BNE loop
in the track loader part...
Re: Resetting IRQs
Posted: Wed Feb 07, 2024 4:37 pm
by groepaz
I'd just ask Krill to port his loader...
I am used to no OS in the way as switched off on C64/Atari800 anyway