Re: 80-bit subnormals printed incorrectly on Debian 11 M68K
On Thu, Jul 22, 2021 at 07:32:49PM +1000, Finn Thain wrote:
> > $ cat /proc/cpuinfo
> > CPU: 68030
> > MMU: 68030
> > FPU: 68882
>
> I wonder if that hardware should be expected to give the same result as
> 68040 hardware (?) Both QEMU and Aranym emulate the latter:
>
> CPU: 68040
> MMU: 68040
> FPU: 68040
The m68k PRM does document some minor differences between the 68881/68882
and the built-in FPU in the 68040 (other than the obvious unimplemented
instructions in the 68040), but I don't think any of it would rise to
this level. They're almost entirely compatible. My first guess would be
an emulation bug. This is the sort of thing that would likely be easy to
get wrong.
My apologies for not having any of my 68040 systems available for a test
on the real hardware. I'm not even sure if any of them still work.
Brad Boyer
flar@allandria.com
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