Re: [hatari-devel] EmuTOS machine support information

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On 16/05/2020 at 23:06, Roger Burrows wrote:
I noticed that Hatari cross-checks the version of Atari TOS against the machine
type.  It checks EmuTOS as well, but more crudely since EmuTOS version numbers
(and the version of Atari TOS announced by EmuTOS) are not 100% useful.

The TOS version specified in EmuTOS ROM header is meaningless. I hope that Hatari doesn't use it for anything. If it actually does, that's wrong. Any Hatari check regarding to the TOS version must be disabled in case of EmuTOS.

Before EmuTOS extended header (available in current snapshots and future releases), the only relevant information about EmuTOS is the ROM size.
- 512 KB: full-featured, all machines
- 256 KB: ST / STe (but not TT or Falcon)
- 192 KB: ST only (including Mega ST)

It would indeed be good that Hatari checks that, to avoid people complaining that i.e. 192k EmuTOS ROM doesn't work with Falcon settings.

EmuTOS now has an extended header which we can put useful information into.
Would it be helpful to Hatari if I added flag bits to indicate which hardware
this ROM can run on; for example, runs on ST hardware / runs on STe hardware /
etc ?  If so, now would be a good time for me to add this.

Good idea.
So if EmuTOS is detected but the extended header is not present, the above rules still applies. But if the EmuTOS extended header is present, its information will override the above hardcoded rules.

That would allow someone, for example, to build a 192k ROM for Falcon (for any obscure reason), and avoid Hatari to complain in that unusual case.

The new EmuTOS flags could be:
1) Supported Atari machines: ST, STe, TT, Falcon, ARAnyM
2) Supported CPU: 68000, 68010, 68020, 68030, 68040, 68060

They must be bitfields, so multiple hardware can be supported by a single ROM. Typically, by design, etos512k.img will support everything (except ColdFire).

So Hatari could reliably issue warnings like:
"Warning: This EmuTOS version is not designed to run on TT. Do you want to try anyway?"

That would be great, and relatively easy to implement.

Vincent Rivière

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