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Old 02 December 2018, 17:36   #1
Warty
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Detecting non-EHB 8362R5 Denise chip via software?

I'm working on a game for OCS Amigas. Mostly as a learning exercise for me, getting familiar with developing in C on the Amiga. My splash screen I did in EHB mode, 320x400. Looks great in UAE, and on a A2000, but on my own A1000, it looks awful. Some googling revealed that quite a few of the US A1000s shipped with an older version of the Denise (because Commode-door had a stock of old chips it wanted to use up OF COURSE). The 8362R5 Denise doesn't have EHB mode.

Reference:
http://eab.abime.net/showthread.php?t=34767&styleid=4
https://groups.google.com/forum/#!ms...Q/5qnZJg7ts5cJ

Dale Luck made a little app back in 1985 (see 2nd post above) that helps a user VISUALLY test whether they have EHB mode. Looking at the code, it's just displaying all 64 color registers in EHB mode, and if user doesn't see dimmer versions, well, they know they have a non-EHB Denise. I'd like to be able to test in software, and then do something different for A1000s with no EHB.

Has anyone seen anything, or have ideas on, how to detect lack of EHB? Intuition knows about EHB, so I think anything I do in intuition will probably just happily continue without any errors. Is there maybe a hardware register I could check, something like that?
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Old 02 December 2018, 18:30   #2
Toni Wilen
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Perhaps bitplane (plane 6) to bitplane or bitplane to sprite collisions work differently in this situation.

But most likely it isn't possible.
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Old 04 December 2018, 02:08   #3
Warty
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Thanks for answering. I'm going to go ahead and surrender for now.
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Old 04 December 2018, 07:29   #4
frank_b
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I have a yankee a1k which doesn't support EHB too. It's from 1985 according to the sticker on the back. My PAL 1k supports EHB.
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Old 04 December 2018, 13:16   #5
NorthWay
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Shouldn't the sprite-bitplane collision check be good enough to test it?
Do you need someone to code up a test for you?

It would be good to know if such a difference can be detected.
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Old 04 December 2018, 18:53   #6
coder76
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Well, does the 3+3 bitplane dual playfield mode work? If it does, then the 6th bitplane should also work.
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Old 04 December 2018, 19:00   #7
Toni Wilen
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Dual playfield and HAM should work normally. Only EHB mode is missing, plane 6 is ignored in color palette selection (which most likely means collisions are not affected)
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Old 08 December 2018, 16:26   #8
Toni Wilen
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I made very simple sprite to plane 6 in EHB mode collision test program: http://www.winuae.net/files/b/ehbtest.zip Run without startup-sequence! There is no proper startup-code etc..

Screen has bars (red background, bars should be dark red if EHB supported, black if not, please confirm) and tiny sprite is moving horizontally. Screen flashes when sprite to bitplane collision is detected. Planes 1 to 5 are blank (zero data only), only plane 6 has non-zero data.

Untested, I don't have non-EHB Denise.
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