Re: Considering EOL of HP320/330/350 (Re: NetBSD/virt68k booting multi-user)

[email protected] (Jason Thorpe) writes:

>> I should have asked this earlier, but now is the good timing:
>> "I'm considering dropping support of (at least) HP320 and =
>HP318/319/330"

>Boo :-(  I mean, I regret getting rid of my (pretty stacked) 9000/380 =
>many years ago, but there was a time I had easy access to 319, 320, and =
>350 models, although, alas, I did not own them.

>> The reason why is it looks memory bus design of these hardware
>> don't support CAS instruction.

>I need to go back and re-read the signal description in the 68020 =
>manual, I guess.  But, yah, the r/m/w instructions do assert a =
>=E2=80=9Clock=E2=80=9D signal, I think.


68020 uses a separate lock signal, 68000 uses a combined
read and write cycle.

On a uniprocessor, you could implement everything with
regular read-modify-write instructions. E.g. BSET does
the same as TAS. Emulating CAS with TAS is more work.