Black screen during some demos

[Yesideez]

That's really strange because I wrote it on a real A1200 back in 1997 (boot and hold down RMB to see other message in bootblock) and it worked fine!

[Toni Wilen]

Originally Posted by Yesideez

That's really strange because I wrote it on a real A1200 back in 1997 (boot and hold down RMB to see other message in bootblock) and it worked fine!

Interesting. I can't get anything else than black screen (after quick intro text), via Indivision AGA or RGB or composite.

Perhaps there is different Lisa revisions that work slightly differently when display window start or end has "illegal" values. Unfortunately I don't have other AGA Amigas.

[Yesideez]

I've had it available for download for over a year and it's been on a fellow ex-A51 member's site for about 2 years and neither of us have had any feedback to say it doesn't work!

I think we'll have to put it down to different Lisa revisions as you say - very strange!

[StingRay]

Originally Posted by Toni Wilen

This means you did change DIWSTRT when hpos value had already passed old DIWSTRT horizontal position (and before old DIWSTOP)

That makes sense but I am not sure that the explanation is that simple.
Because, where do the old DIWSTRT/DIWSTOP values come from? As I only set them one time in the copperlist and never changed them, i.e. there's only 1 dc.w $8e,xx dc.w $90,xx in the copperlist. Or did I misunderstand you?

Originally Posted by Toni Wilen

You can duplicate the black screen easily if you first set DIWSTRT and DIWSTOP to normal-like values, wait 2 lines and immediately set 00/FF values at the very beginning of line. If you wait until middle (horizontally) of screen before doing the change, no black screen

Tried this and the behaviour was exactly as you described, interesting "feature".

Originally Posted by Toni Wilen

btw, I also finally tested Atmospherical Melodies on my real A1200: black screen as expected, function keys change music normally.

Can you try attached executable on your A1200? It is my test effect (a crappy 1 bitplane twister) with the "interesting" DIWSTRT/STOP settings and works on my A4000.

[Toni Wilen]

Originally Posted by StingRay

That makes sense but I am not sure that the explanation is that simple.

Check http://eab.abime.net/showpost.php?p=627136&postcount=59 and following posts for technical explanation.

Can you try attached executable on your A1200? It is my test effect (a crappy 1 bitplane twister) with the "interesting" DIWSTRT/STOP settings and works on my A4000.

I don't have any fast way to transfer files at the moment.

[Yesideez]

Just disassembled the bootblock and the copperlist is:

CuList	dc.w	$2001,$FFFE
	dc.w	$100,$0200		;BPLCON0
	dc.w	$8E,$0581		;DIWSTRT
	dc.w	$90,$40C1		;DIWSTOP
	dc.w	$92,$38			;DDFSTRT
	dc.w	$94,$D0			;DDFSTOP
	dc.w	$102,0			;BPLCON1
	dc.w	$104,$24		;BPLCON2
	dc.w	$108,0			;BPL1MOD
	dc.w	$10A,0			;BPL2MOD
	dc.w	$E0,7			;BPL1PTH
	dc.w	$E2,$EF00		;BPL1PTL
	dc.w	$8E0F,$FFFE
	dc.w	$180,$0FF0
	dc.w	$182,$0FFF
	dc.w	$8F01,$FFFE
	dc.w	$180,$0640
	dc.w	$900F,$FFFE
	dc.w	$100,$1200
	dc.w	$9F0F,$FFFE
	dc.w	$100,$0200
	dc.w	$A00F,$FFFE
	dc.w	$180,$0FF0
	dc.w	$A10F,$FFFE
	dc.w	$180,0
	dc.l	-2

Ripped the main exe from the disk (offset $400, length $3a00, data $70000) and it's been crunched but I can't remember how or what with - I'm suspecting CrM or STC. I say how because I think I modified the decrunch routine slightly to prevent it unpacking if ripped as xfdlist shows it as being uncrunched when it definitely is. ReSource shows it as unpacking to absolute $30000.

OK, I got bored...

[Toni Wilen]

No need to rip anything if you want to check the copper list, disassemble etc.. Press SHIFT+F12 in winuae.

[StingRay]

Originally Posted by Yesideez

and it's been crunched but I can't remember how or what with - I'm suspecting CrM or STC.

It is packed with CrM. I already decrunched it yesterday (by hand, not using any tools) to check if it would work with normal DIWSTRT/STOP settings and it did.

[Yesideez]

Is there a manual for that debugger anywhere? Never knew that was there!

[StingRay]

When in the debugger, just type "?" to get a short help for the available commands. I don't think a manual exists.