Re: [hatari-devel] TOS 3.06 does not boot from ACSI

[Thomas Huth <th.huth@xxxxxx>]

Am Wed, 05 Oct 2016 17:32:48 -0400
schrieb "Roger Burrows" <anodyne@xxxxxxxxxxxx>:

> On 5 Oct 2016 at 21:15, Thomas Huth wrote:
> > OK, thanks, that's good to know ... but apparently, TOS 3.06 also
> > reads the value from the VME bus GPIO register ... maybe as a fall
> > back if the NVRAM is not containing a sane value?
> >   
> I don't think so.  $ffff8e09 is an SCU general purpose register.
> IIRC, TOS3 sets a bit to indicate that this is a warm boot.  I can
> investigate further if you need.  I believe it should be read as 0x00
> on a cold boot.

Thank you also very much for that information, Roger! The warm boot bit
seems to be the lowest bit in that register - TOS 3.06 actually writes
a 0x01 into the register during boot.

Actually, we even already have this code since quite a while in
stMemory.c of Hatari:

 /* On TT, set bit0=1 at $ff8e09 to simulate a warm start */
 /* (else memory detection is not skipped after a cold start/reset) */
 if (Config_IsMachineTT())
	STMemory_WriteByte ( 0xff8e09, IoMem_ReadByte(0xff8e09) | 0x01 );

I must have been really blind yesterday that I did not spot this
earlier... :-/

 Thomas