Re: PPC incompatible software

Mike Dee <mikedee@emteedee.invalid> wrote:

Patrik Schindler wrote:
 

any of you observe another software which reproducibly crashes only on PPCs
but not on 68k Macs?

 
Yes, this will occur for any 68k encoded Mac software that requires Floating
Point Math, i.e.; an onboard FPU to be present. This is a 68k FPU that's
required, not a built-in PPC FPU.

Ah, that's a good hint, thanks!

Not saying this is the cause of your 68k program not working on PPC
hardware. Only, that it does occur for any 68k program that requires
floating point math.
>
Another cause of 68k software being unable to run on PPC Macintosh, is any
68k software that requires the presence of a Memory Management Unit (MMU).
<https://en.wikipedia.org/wiki/Memory_management_unit>

The system requirements according to the package are a Mac Plus and System
7.0. For the client, and that's what I'm talking about. That one has neither
an FPU, nor an MMU. But maybe the emulator code uses a gestalt call to know
what kind of machine it's running on, and dynamically branches to differently
optimized code? On the other hand, we're talking about a terminal emulator.

I dimly remember MacsBug stating an unimplemented instruction or trap which
supports your thinking. I'll try an 68k FPU emulator and check if this fixes
the error.

Again, thanks for the hint!

PPC's 68k emulation does not emulate a 68k MMU either, and I don't know
of a 3rd party soulution to this one. It is however, rare for 68k
software to demand this. It happens, but it's rare.

I guess that the requirement for an MMU is more an OS thing. Maxima comes to
mind: A control panel extension to provide virtual memory when running System
6.

--

:wq! PoC