IRQ ASM pb

[LeCaravage]

Hi,
I must admit that irq programming is something I'm not sure to master, but to be honest I've never understand its mechanics.

I use P61 music routine in lvl6 IRQ. I also use another one, but at a lower priority : lvl3 for instance.
The lvl6 irq is never turned off during main loop, but the lvl3 one is turned on/off 2 times.
The lvl3 irq is somehow turned off after a while, even though it shouldn't. The result is my program freezes, because main program waits indefinitely for an unlock semaphor coming from lvl3 irq, which will be never set.
I suspect it's because I'm not using the irqs turn on and off right. I'm unsure because Seka doesn't give contain of $09A and $09c after a breakpoint.
I always use $dff09a AND dff09c to turn on and off irqs amongst other flows (I guess but unsure).

Finally, so my question is :

What advices could you give and what is the proper way to turn on and off irqs in a main programm ?

[buzzybee]

For Proxima 3 I use OS-controlled interrupts, since this feels more stable to me than having to care about interrupts all myself. Especially as I am using a rather interesting setup of copper interrupt to init software interrupt for timing reasons / avoid possible conflicts with vertical blank interrupt

Initcode looks something like this:

	lea	CopIntServer(pc),a1
	moveq  #4,d0
	CALLEXEC	AddIntServer         ;Add copper interrupt to system list
	lea	VBLIntServer(pc),a1
	moveq  #5,d0
	CALLEXEC	AddIntServer         ;Add vb interrupt to system list


CopIntServer
	dc.l  0,0                     ;ln_Succ,ln_Pred
	dc.b  0,9                     ;ln_Type,ln_Pri
	dc.l  CopIntName                 ;ln_Name
	dc.l  0,copperInt             ;is_Data,is_Code
VBLintServer
	dc.l  0,0
	dc.b  0,
	dc.l  VBLIntName
	dc.l  0,vertBlancInt
SoftIntServer	; no active server, init'ed by copper interrupt
	dc.l  0,0
	dc.b  0,9
	dc.l  softIntName
	dc.l  0,softInt

CopIntName	dc.b "RP3_CopServ",0  
VBLIntName	dc.b "RP3_VBLServ",0 
softIntName	dc.b "RP3_SoftServ",0

Interrupts themselves are basic subroutines, ending with rts

copperInt
	SAVEREGISTERS
....
	lea	SoftIntServer(pc),a1
	CALLEXEC Cause	; init software interrupt, delegate further 50 hz code handling without blocking vbi and coper interrupt chain
.skipIntCall
	RESTOREREGISTERS
	rts

And to remove servers from the list of active interrupts:

	lea	CopIntServer(pc),a1
	moveq  #4,d0
	CALLEXEC	RemIntServer         ; remove copper interrupt
	lea	VBLIntServer(pc),a1
	moveq  #5,d0
	CALLEXEC	RemIntServer         ; remove vertical blank interrupt

[LeCaravage]

I use a similar scheme but in main program for add/remove/processing objets (real or virtual bobs).

The pb is I turn off system, so knowing what contains 'addintserver' and remintserver' could be interesting.
Anyway thanks for your help.

[hooverphonique]

Originally Posted by LeCaravage

Seka doesn't give contain of $09A and $09c

Those registers cannot be read, in fact all of the custom chip registers are either read or write, not both. Could that be the source of your problems (reading the wrong registers) ?

[LeCaravage]

Originally Posted by hooverphonique

Those registers cannot be read, in fact all of the custom chip registers are either read or write, not both. Could that be the source of your problems (reading the wrong registers) ?

Checked again but I don't get a read access to these registers. I didn't know there's no R/W custom registers on Amiga, I've probably mixed things with some C64 registers.

Could it be possible the P61 replay alters other irq bits in $dff09a other than lvl6 one ?

[hooverphonique]

Originally Posted by LeCaravage

Could it be possible the P61 replay alters other irq bits in $dff09a other than lvl6 one ?

I don't know, but potentially it could be altering INTEN (bit 14) master interrupt enable.

[LeCaravage]

Originally Posted by hooverphonique

I don't know, but potentially it could be altering INTEN (bit 14) master interrupt enable.

What is the use of this specific bit ?

Is there some cases where a lower irq could interrupt an aldready running higher one ?

[LeCaravage]

Originally Posted by hooverphonique

I don't know, but potentially it could be altering INTEN (bit 14) master interrupt enable.

I tried to disable bit 14 but the sound is turned off.

I just discovered that $09A and $09C can be read via $01C and $01E.

I added backgound color changes into the main loop of P61 replay and I noticed that it seems to freezes always at the same raster line. Very strange.

[Tomislav]

Here is information of Amiga hardware access:
http://amiga-dev.wikidot.com/information:hardware

[LeCaravage]

Originally Posted by Tomislav

Here is information of Amiga hardware access:
http://amiga-dev.wikidot.com/information:hardware

Thanks, indeed usefull site, I'm already using it.


Can someone confirm what I think I understand about $9A, $9C.
The first is a request, the second one is a sort of acknowledgment of the current finishing irq ? (just before the rte).

[Bartman]

It seems P61 also uses INTF_EXTER

[LeCaravage]

Originally Posted by Bartman

It seems P61 also uses INTF_EXTER

You mean the bit #13 of intena ? Do you know the other one ?