[hatari-devel] Small test to run on STE

Konador, Cyprian cyprian.konador at hp.com
Fri Feb 17 12:52:35 CET 2012


> -----Original Message-----
> From: Nicolas Pomarède [mailto:npomarede at corp.free.fr]
> Sent: Thursday, February 16, 2012 22:28 PM
> To: Mailing list for Hatari developers
> Cc: Konador, Cyprian
> Subject: Re: [hatari-devel] Small test to run on STE
> 
> On 16/02/2012 22:03, Konador, Cyprian wrote:
> > My STE doesn't boot with 1MB, therefore I've checked with 2MB and the
> > result is $3f
> 
> thanks, that's interesting. So the STE is masking $ff8205 with $3f (which is the
> maximum possible RAM on STF/STE) whatever the real size of the current
> RAM is (but it's true it would be more complicated to take the RAM size into
> account at the hardware level for $ff8205).
> 
> I will add this to Hatari, as this is the method use by the Delirious Demo IV) to
> detect an STE is used instead of an STF.
> 
> 
> Nicolas
> 

Either STE is masking $ff8205 with $3f or just that register (I mean address / count register, I guess it's managed by MMU.) is only 22bit.

Interesting question is, what will be visible on the screen if we set video address to the end of ST ram $3fffff  - the Alt ram data (rather no, MMU has no access there); noise - bus activity; beginning of the ST ram ram (counter overflow ) ?

BR
Cyprian



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