Re: [hatari-devel] Hatari Falcon 060 emulation observations

[Laurent Sallafranque <laurent.sallafranque@xxxxxxx>]

I just forgot to mention that I added a bad hack just to simplify the 
first researches : in memory.c (hatari code), I change

#define TTmem_end    0x80000000     /* Max value for end of TT ram, 
which gives 2047 MB */

replaced by :

#define TTmem_end    0xffffffff     /* Max value for end of TT ram, 
which gives 2047 MB */


Like this, I give access in TT_RAM to the CT60 I/O memory.
This area should be correctly mapped later when the CT60 TOS boots.

Regards
Laurent




Le 11/11/2018 à 15:28, Laurent Sallafranque a écrit :
> Hi all,
>
> After a few investigations on the CT60 TOS, I manage to go further 
> easily :
>
> Booting hatari in 060 mode with CT60 TOS without changing anything 
> always stops with the message "no SDRAM"
>
> If I add a Breakpoint here (in the ct60_configure_sdram function)
>
> 00e9adb2 : 6a00 00b8                          bpl       $e9ae6c
>
> and I change PC like this :
>
> r pc=$e9ae6c
>
> Hatari goes much much far :
>
> SDRAM 64 MB detected          (((which is the default value when all 
> I/O registers $F2xx0000 are set to 0)))
>
> Boot V1.03c 2005 July
>
> keyboard OK
> wait 30 seconds for the floppy A
> SCSI 0.1 ... no answer
> SCSI 1.1 ... no answer
> SCSI 2.1 ... no answer
> SCSI 3.1 ... no answer
> SCSI 4.1 ... no answer
> SCSI 5.1 ... no answer
> SCSI 6.1 ... no answer
> SCSI 7.1 ... no answer
>
> IDE 0.0
> And here I got : EXCEPTION PROCESSING 2: Access Fault and a debugger 
> message appears with the registers.
>
>
> To bypass the SDram I2C protocol detection without patching the TOS 
> itself, it seems we can just patch one instruction directly in 
> hatari's rom by changing the instruction "bpl $e9ae6c"  to  "bra 
> $e9ae6c".
>
> If we want to get the correct memory size, we'll have to feed the 
> correct values to $f2xx0000 adresses (memory size, memory bank 
> organisation, ...). We can set these values when hatari boots in 060 
> mode and TTram is > 0.
>
> I continue to have a look at it and see if I can understand the 
> Exception.
>
> Regards
> Laurent
>
>
>
>
>
> Le 10/11/2018 à 10:46, Nicolas Pomarède a écrit :
> > Le 09/11/2018 à 23:45, Eero Tamminen a écrit :
> > > "Somebody" would first need to add necessary emulation additions
> > > (or TOS patches) to get CT60 TOS working first, so that there's
> > > a TOS version that emulates the FPU opcodes missing from 060...
> > >
> > > Are you planning on looking into that?
> >
> > for thoses interested in patching tos ct60 (to change sdram check for 
> > example), note that the sources are here : 
> > https://github.com/mikrosk/ct60tos
> > this can give better insigth on which tests are done instead of just 
> > disassembking the ct60 tos.
> >
> > Nicolas