|Re: [hatari-devel] TOS 3.06 does not boot from ACSI|
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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) */
STMemory_WriteByte ( 0xff8e09, IoMem_ReadByte(0xff8e09) | 0x01 );
I must have been really blind yesterday that I did not spot this