Chuck Rock 1, compatiblity issues on Amiga 1200 ?!?

[vbgd]

Hello,

I`m trying to start the ipf-Image of Chuck Rock written back to disks with my kryoflux on my Amiga 1200. Are there any compatiblility issues?

[jotd]

what happens when you run it? do you have issues?

[vbgd]

Guru meditation after short access to the first disk. Cracked adf works..... Maybe RNC copyprotection is an issue or is the ipf buggy?

Both availible ipf-releases are not working, 0767 and the Europe release.

[dlfrsilver]

Originally Posted by vbgd

Guru meditation after short access to the first disk. Cracked adf works..... Maybe RNC copyprotection is an issue or is the ipf buggy?

Both availible ipf-releases are not working, 0767 and the Europe release.

Normal. Those are A500 games, not A1200. For A1200, we have whdload.

your A1200 doesn't like the RNC protection.

[Nobby_UK]

Yup A1200 emu of IPFs = 80000008 00002720

[Galahad/FLT]

OK, so reason is because of the stupid way the game tries to setup supervisor mode, it assumes a certain type of stack frame which won't work on A1200, game could be fixed from the bootblock to overcome this problem however quite easily.

[vbgd]

Thx a lot, under which folder / year can I find it? Which tool can I use to write the bin? Or how to access the zone directly? I need to upgrade my account.

[Galahad/FLT]

Originally Posted by vbgd

Thx a lot, under which folder / year can I find it? Which tool can I use to write the bin? Or how to access the zone directly? I need to upgrade my account.

Forget that, attached to this message is a file called "chuckrockwriter.nfo", download that and copy it to ram or hard drive or floppy and run it.

Ignore the .nfo extension, its a usual Amiga .exe file, but the system this board employs only allows certain file types.

So in the CLI you would type "chuckrockwriter.nfo" and hit RETURN.

You will then be presented with some text.

Now stick in your Kryofluxed copy of Disk 1 into DF0:

Wait for disk activity to finish, ignore any disk requesters, and then hit left mouse button, it will write the new bootblock to your disk 1.

This will fix the boot problem, I PRESUME that Kryoflux can correctly write back the Copylock track, if it can't, then you won't get to see the intro as it does a protection check quite early.

Let me know how you get on.

[vbgd]

Account upgraded, found the bin in the zone.

Now downloading your attached file to replace the bootblock.

[Galahad/FLT]

Originally Posted by vbgd

Account upgraded, found the bin in the zone.

Now downloading your attached file to replace the bootblock.

Yeah dont worry about that file in the zone, the attached file does everything in its place

[vbgd]

Done, it works!! Thank you very much!

[Galahad/FLT]

Originally Posted by vbgd

Done, it works!! Thank you very much!

[Nobby_UK]

Works (emulated) but requires a quick 3 finger salute

[vbgd]

[Foebane]

Is this minor change (with a simple fix as described above) the reason that Chuck Rock (and many many A500 games) were listed as incompatible with the A1200? As listed in Amiga Format and other magazines?

Honestly, didn't these game developers know about the A1200 differences? Or didn't care?

WHDLoad has been a revelation in that regard, with easy fixes to existing floppies!

I also wondered, when AGA came out, if the incompatibilities were due to the chipset, but apparently not.

[gimbal]

Originally Posted by Foebane

Honestly, didn't these game developers know about the A1200 differences? Or didn't care?

All of the above. Didn't know, didn't care, didn't care to know. If the publisher is okay with the game being specifically targeted at the A500 then why invest time and money into debugging it on other machines?

[jotd]

I also wondered, when AGA came out, if the incompatibilities were due to the chipset, but apparently not.

it could happen but was pretty rare (wrong activation of AGA features by not setting bits to 0, using undocumented ECS features like in SWIV highscore...). And game didn't crash because of that.

The most frequent reasons were:

- faster CPU => blitter waits missing => corruptions => crashes
- faster CPU => game becomes unplayable
- when detecting expansion, assuming that if a write to $200000 is okay then there's fast ram there (where it's just chipmem wrapping to 0)
- self-modifying code
- abuse of 68000 CPU prefetch (HLS protection)
- different CPU => different stackframe: hardware protections could fail because of that
- instructions becoming privileged on 68020+ (move SR => move CCR)
- storing (or not clearing) the most significant byte of memory addresses. Okay on 680EC20 but fails on a full 32-bit (Xenon 2)

I could go on and on

[Phantasm]

Originally Posted by Foebane

Is this minor change (with a simple fix as described above) the reason that Chuck Rock (and many many A500 games) were listed as incompatible with the A1200? As listed in Amiga Format and other magazines?

Honestly, didn't these game developers know about the A1200 differences? Or didn't care?

WHDLoad has been a revelation in that regard, with easy fixes to existing floppies!

I also wondered, when AGA came out, if the incompatibilities were due to the chipset, but apparently not.

Reasons for incompatibilities can be many. CPU differences, Chipset differences, Kickstart versions. Sometimes very easy to fix (as above) and other times much more difficult.

[DanScott]

Originally Posted by Foebane

Honestly, didn't these game developers know about the A1200 differences? Or didn't care?

The A1200 didn't exist when many of these games came out.

Chuck Rock came out sometime in early 1991

[jotd]

plus all arcade games used direct hardware banging disregarding future compatibility because if you code a game using system friendly routines you end up with:

- less memory
- weaker protections
- game crawling