Japtro STe Fix ?

[Orion_]

Is there any fix/patch for Japtro on STe ?
I really like this demo and can't watch it my STe, the machine reboot just after the rotating starfield begins at the beginning of the demo

Edit:
I finally took some time to patch this nice demo.
Here is the disk patched for STe:
Enjoy ! http://onorisoft.free.fr/atari/japtro_ste.zip

[npomarede]

The demo runs under Hatari STE TOS 1.62, so I think it should work on real STE too.
Are you sure it's not your floppy which is damaged ?

[Orion_]

The demo runs under Hatari STE TOS 1.62, so I think it should work on real STE too.
Are you sure it's not your floppy which is damaged ?

I use a floppy emulator, so ...
And it's on the list of demo that doesn't work on STe: http://www.atari-forum.com/viewtopic.php?t=1570
(it also crashes the same way on Steem SSE)

[npomarede]

But is it referenced on Steem page because it's not correctly emulated yet, or because Japtro is really not compatible with STE ?
Maybe someone else here could report if it works on his STE.

[Orion_]

ok I tried to watch the difference between STF and STe behavior on this demo using Steem debugger

Timer A routine @ $00A388 is started just at the white screen after the screaming sangoku picture.
The problem is, this routine writes to the A1 register which should contain the YM register address $FF8800.
But instead, during that white fading (2 frames), it contains the address $09FBCA, so, the Timer A routine writes junk in the memory.
and specifically at the $09FBCE address which is later used as an index to fetch an address in a table. (Code at $A0D0 / $A0F2)
on STF this index is 0, on STe it is $EC00, which give the wrong offset address, and when writing at this wrong address, it crashes (at $A11A)
I'm not sure why there is this difference on STF or STe about this, maybe a different Timer A behavior.

[simonsunnyboy]

Yes, Timer A has special behaviour on STE, together with DMA sound. But I do not have any details at hand...IIRC it was described in Paranoid's STE FAQ:

[lotek_style]

As far as I remember the demo worked fine on my STe back in the day.

[Steven Seagal]

Demo depends on CPU/MFP ratio, which certainly varied between STEs.
It loops on my STE like in Steem SSE 3.7.2.

[troed]

Demo depends on CPU/MFP ratio, which certainly varied between STEs.
It loops on my STE like in Steem SSE 3.7.2.

IIRC the "only" difference is between between PAL and NTSC STEs (8.02 vs 8.05MHz).

(On ST there are a few others as well)

[Orion_]

I finally took some time to patch this nice demo.
Here is the disk patched for STe, working on Steem SSE, it should work on a real STe
(since Steem was having the same crash behavior I had on my STe)
Enjoy ! http://onorisoft.free.fr/atari/japtro_ste.zip

[Brume]

Thanks for sharing, Orion ! I like very much this demo, too

[lotek_style]

What was to patch? It worked fine on my old STe back in the day.

[Orion_]

What was to patch? It worked fine on my old STe back in the day.

It wasn't working on my STe nor Steem SSE pretty accurate emulation, so ... maybe you could try again on an STe to see if it's working or not ?
Patch detail in the readme. (but I don't know exactly why there is a difference between ST and STe behavior)

[lotek_style]

Maybe it's due to different TOS? I don't have the same machine that I had in the early 90's anymore but I can try on my current STe with 4 MB.

[Steven Seagal]

What was to patch? It worked fine on my old STe back in the day.

It wasn't working on my STe nor Steem SSE pretty accurate emulation, so ... maybe you could try again on an STe to see if it's working or not ?
Patch detail in the readme. (but I don't know exactly why there is a difference between ST and STe behavior)

Thx for the compliment (Steem SSE pretty accurate emulation), although in this particular case I'm not sure it is accurate (CPU/MFP clock ratio), there could be another reason, like faster chipset. It's a TODO for me.

What is sure: have the loop effect on my real STE too (4MB, TOS 1.62 UK), that's why Steem SSE behaves this way.

[Steven Seagal]

Confirmed on my STE, original loops at first screen, your patched version passes.