It's no more a MiSTery

[sebdel]

I found a bunch of articles that explain pretty well how it's connected to the MCU and the roles of BR, BG and BGACK but that doesn't tell much about the internals of the blitter. I mean, do you think the internal state machine would need to be rewritten?

The blitter is not my work, it's the original from Till Harbaum. I just made it somewhat compatible with the FX68K, and the 3-way handshaking of the bus arbitration, which is not in TG68K. That didn't make it more compatible with demos. I think the best would be to use the original schematics (which worked pretty well for the GSTMCU). But it's not a trivial work.

Bummer. There's a higher chance of me patching 0913 rather than rewriting the blitter.

[slingshot]

Bummer. There's a higher chance of me patching 0913 rather than rewriting the blitter.

Just added a patch, and now at least doesn't freeze or corrupts the screen. If you can find out while the music is not started after the selection, maybe it would be to possible fixing that, too.

[sebdel]

Bummer. There's a higher chance of me patching 0913 rather than rewriting the blitter.

Just added a patch, and now at least doesn't freeze or corrupts the screen. If you can find out while the music is not started after the selection, maybe it would be to possible fixing that, too.

Thanks, that's exactly the kind of patch I thought I might pull off given a couple of weeks of trial and error.
I'll try to guess what happens with the music. I just lost an afternoon figuring out that the PRG is compressed and disassembling it is entirely pointless

[slingshot]

Thanks, that's exactly the kind of patch I thought I might pull off given a couple of weeks of trial and error.
I'll try to guess what happens with the music. I just lost an afternoon figuring out that the PRG is compressed and disassembling it is entirely pointless

Yeah, usually tracing in an emulator is the way to go.

[sebdel]

Thanks, that's exactly the kind of patch I thought I might pull off given a couple of weeks of trial and error.
I'll try to guess what happens with the music. I just lost an afternoon figuring out that the PRG is compressed and disassembling it is entirely pointless

Yeah, usually tracing in an emulator is the way to go.

I could depack it actually, it uses UPX, a modern binary packer that supports Atari, how nice of them, I had no idea such a thing existed.
Not much progress yesterday, I tried your latest patch that indeed improves stability of 0913 (but still no sound), and then it occured to me that it may help with other modern STe productions so I got a bit sidetracked.

Takeaways on modern demos:
- Motus works perfectly
- We were @ probably works but my monitor can't handle it :/
- lots of stuff these days are distributed as "MSA". I don't know if there's a big difference with ".ST" but support for MSA would be nice.

Older stuff:
- How to use The ventura demo: the disk number appears right next to the screen title. Insert the correct disk BEFORE you press space.
- The Ventura/Board and spheres screen properly displays the naos logo up in the syncscrolling lines. That's quite an achievement, it worked on 50% of atari st out there from our observations.
- The Big demo needs TOS1.02
- There are tons of corrupted TOS images out there (esp. [fr]) so if you have a demo that don't start, make sure you can boot to desktop first.

Bugs:
- Soft Reset does not always jump into the reset demos (electra). It seems to work only for older TOS. I don't know if that's expected.
- After the big demo reset screen, there's a reset that does not resets the YM2149. You get a rebooted machine with noise coming out of the audio.

[slingshot]

I still wouldn't make high-stakes investments on STe demos, they like if the blitter does its job in exactly the same cycles as the original. Even there's a game (Lethal Xcess) which requires cycle-perfect blitter.

MSA is just the ST with a header, and optional compression. Not a hardware friendly format.

Yeah, Electra doesn't work with TOS2.06. But it's not unexpected at all.
The CPU reset instruction currently resets IKBD only, while in reality it should reset all peripherals. YM2149 can be added easily.

[jamesrc]

Hopefully I'll get back to trying things out this weekend.

I don't know any 68000 I'm afraid, slingshot, otherwise I'd try to provide more information. (I know plenty of Z80 but that's not much help here).

One day I'll teach myself, but having a young child means it isn't going to be soon.

[sebdel]

I still wouldn't make high-stakes investments on STe demos, they like if the blitter does its job in exactly the same cycles as the original. Even there's a game (Lethal Xcess) which requires cycle-perfect blitter.

MSA is just the ST with a header, and optional compression. Not a hardware friendly format.

Yeah, Electra doesn't work with TOS2.06. But it's not unexpected at all.
The CPU reset instruction currently resets IKBD only, while in reality it should reset all peripherals. YM2149 can be added easily.

You did it once again, thanks for the patch. Why are you only connecting peripheral_reset to the MFP and YM though? From the schematics it seems XRESET is all over the place, starting with the blitter?

[slingshot]

You did it once again, thanks for the patch. Why are you only connecting peripheral_reset to the MFP and YM though? From the schematics it seems XRESET is all over the place, starting with the blitter?

Do you think is there any demo out there which must reboot and reset the blitter?
ACIA, DMA and the Shifter don't even have a reset pin, so blitter and FDC can be added, if turns out something need it.

[sebdel]

You did it once again, thanks for the patch. Why are you only connecting peripheral_reset to the MFP and YM though? From the schematics it seems XRESET is all over the place, starting with the blitter?

Do you think is there any demo out there which must reboot and reset the blitter?
ACIA, DMA and the Shifter don't even have a reset pin, so blitter and FDC can be added, if turns out something need it.

Of course it's probably useless. I was asking because I was under the impression that the way you implemented this core was to match the schematics period.

[slingshot]

Of course it's probably useless. I was asking because I was under the impression that the way you implemented this core was to match the schematics period.

Of course, I try. But I reserve the right for some freedom Did you know the MegaSTE external keyboard doesn't have the reset line, so ikbd reset doesn't work there?

[slingshot]

The Union Demo - Level 16 fullscreen fails to load, just goes back to the main menu. The original on AtariMania is a STX, so I've had to use the version on POV112 from pouet.net. Issue exists in ST and STE mode.

I've found the issue, however the fix has a conflict how I interpret a part of the STe schematics. Is it possible to test this on a real STe?

[Total Eclipse]

The Union Demo - Level 16 fullscreen fails to load, just goes back to the main menu. The original on AtariMania is a STX, so I've had to use the version on POV112 from pouet.net. Issue exists in ST and STE mode.

I've found the issue, however the fix has a conflict how I interpret a part of the STe schematics. Is it possible to test this on a real STe?

I don't have access to STe, both myself and friends only have STfm. Hopefully someone on here can test shortly.

[RealLarry]

The Union Demo - Level 16 fullscreen fails to load, just goes back to the main menu. The original on AtariMania is a STX, so I've had to use the version on POV112 from pouet.net. Issue exists in ST and STE mode.

I've found the issue, however the fix has a conflict how I interpret a part of the STe schematics. Is it possible to test this on a real STe?

I don't have access to STe, both myself and friends only have STfm. Hopefully someone on here can test shortly.

I can test this tomorrow morning CET, if I'm not too late. Too drunk now Anybody a download link for this demo?

[slingshot]

I can test this tomorrow morning CET, if I'm not too late. Too drunk now Anybody a download link for this demo?

https://www.exxoshost.co.uk/atari/games ... (1992).zip

Select Union Demo, then walk to the L16 door.
Thanks!

[RealLarry]

I can test this tomorrow morning CET, if I'm not too late. Too drunk now Anybody a download link for this demo?

https://www.exxoshost.co.uk/atari/games ... (1992).zip

Select Union Demo, then walk to the L16 door.
Thanks!

Just tested this demo, Level 16, but after loading I was exited back to be in front of the Level 16 door. Machine is a STE/TOS 1.62/4MB
I'll leave this setup for further testing, if needed. I took the opportunity to update this "grab&play" machine with ParCP, JayMSA and other needful tools, so I can test instantly now (all other Ataris are somewhat fixed in furnitures

[slingshot]

Just tested this demo, Level 16, but after loading I was exited back to be in front of the Level 16 door. Machine is a STE/TOS 1.62/4MB

That's cool! It's how STe should behave according to the ASIC schematics (and I've implemented it correctly then). No emulator does this.

[RealLarry]

Just tested this demo, Level 16, but after loading I was exited back to be in front of the Level 16 door. Machine is a STE/TOS 1.62/4MB

That's cool! It's how STe should behave according to the ASIC schematics (and I've implemented it correctly then). No emulator does this.

Ha! I was afraid at first that this would be NOT the wanted behaviour But okay, then: Good work - as always!

[slingshot]

Ha! I was afraid at first that this would be NOT the wanted behaviour But okay, then: Good work - as always!

It's hard to argue with the original machine's behavior This demo is clearly not designed for STe - just look at the bottom scroller. And even in emulators, which starts the Level 16 fullscreen, it's messed up.

[breiztiger]

hi
just a dub question, is someone work to port this good core to mister ?

[sebdel]

Ha! I was afraid at first that this would be NOT the wanted behaviour But okay, then: Good work - as always!

It's hard to argue with the original machine's behavior This demo is clearly not designed for STe - just look at the bottom scroller. And even in emulators, which starts the Level 16 fullscreen, it's messed up.

I swear the scroller was not messed up in STe mode when I tested it yesterday. It was great to see the L16 fullscreen again, good job
Regarding the Union demo: I'm looking for a proper disk image, I don't like the compilation experience. It seems it's not so easy because of the custom disk format.

[slingshot]

I swear the scroller was not messed up in STe mode when I tested it yesterday.

I'm sure it is

[sebdel]

Thanks, that's exactly the kind of patch I thought I might pull off given a couple of weeks of trial and error.
I'll try to guess what happens with the music. I just lost an afternoon figuring out that the PRG is compressed and disassembling it is entirely pointless

Yeah, usually tracing in an emulator is the way to go.

Following up on this...
A bit of a stab in the dark but I noticed that 0913 sometime freezes to a black screen right around the LMC1992 initialization. Is it implemented? I can't find it. Do you think in can be the cause of the freezes or no sound symptoms?

I don't really understand how that piece of code works, is the mask register moving on its own while it transfers on the MW interface? And what's going on with the SR, do you need to be in supervisor mode when writing to MW but not when reading?

Code: Select all

$00061176 : 40e7                               move      sr,-(sp)
$00061178 : 46fc 2700                          move      #$2700,sr
$0006117c : 31fc 07ff 8924                     move.w    #$7ff,$ffff8924.w
$00061182 : 31c0 8922                          move.w    d0,$ffff8922.w
$00061186 : 0c78 07ff 8924                     cmpi.w    #$7ff,$ffff8924.w
$0006118c : 67f8                               beq.s     $61186           <= There could be an infinite loop here ?
$0006118e : 46df                               move      (sp)+,sr
$00061190 : 0c78 07ff 8924                     cmpi.w    #$7ff,$ffff8924.w     
$00061196 : 66f8                               bne.s     $61190           <= Or here ?
$00061198 : 4e75                               rts

[sebdel]

I don't really understand how that piece of code works, is the mask register moving on its own while it transfers on the MW interface? And what's going on with the SR, do you need to be in supervisor mode when writing to MW but not when reading?

Code: Select all

$00061176 : 40e7                               move      sr,-(sp)
$00061178 : 46fc 2700                          move      #$2700,sr
$0006117c : 31fc 07ff 8924                     move.w    #$7ff,$ffff8924.w
$00061182 : 31c0 8922                          move.w    d0,$ffff8922.w
$00061186 : 0c78 07ff 8924                     cmpi.w    #$7ff,$ffff8924.w
$0006118c : 67f8                               beq.s     $61186           <= There could be an infinite loop here ?
$0006118e : 46df                               move      (sp)+,sr
$00061190 : 0c78 07ff 8924                     cmpi.w    #$7ff,$ffff8924.w     
$00061196 : 66f8                               bne.s     $61190           <= Or here ?
$00061198 : 4e75                               rts

Responding to myself because I can not edit:
- disregard my comment about supervisor, this all happens in an exception vector so it's irrelevant. I still don't see what's the point of restoring SR early though.
- I found the MW doc and indeed, you are supposed to poll the mask register so I understand this code better.If the MW interface is correctly implemented (found it in gstshifter) then all is well with the world

[slingshot]

- I found the MW doc and indeed, you are supposed to poll the mask register so I understand this code better.If the MW interface is correctly implemented (found it in gstshifter) then all is well with the world

It usually waits until the register "turns around". Are you sure it never exits from that loop?
Actually many games are setting the MW, and don't freeze.