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SubjectNeoGeo bios z80 check new Reply to this message
Posted bymasterzog
Posted on09/19/07 06:33 PM



The neogeo bios does a test of the Z80, and hangs with an error message if the Z80 behaves improperly.

How much of the Z80 needs to be emulated to pass this test? Will the Z80 pass on its own (with the ym2610 stubbed out), or does it need parts of the ym2610 as well?





SubjectRe: NeoGeo bios z80 check new Reply to this message
Posted bymasterzog
Posted on09/20/07 01:41 PM



To answer my own question for anyone who's curious:

The bios will be happy with just the Z80. No ym2610 is needed.

> The neogeo bios does a test of the Z80, and hangs with an error message if the
> Z80 behaves improperly.
>
> How much of the Z80 needs to be emulated to pass this test? Will the Z80 pass
> on its own (with the ym2610 stubbed out), or does it need parts of the ym2610 as
> well?
>





SubjectRe: NeoGeo bios z80 check new Reply to this message
Posted byAamirM_Nugen
Posted on09/21/07 00:02 AM



Hi,

As far as I remember you need to return 1 when read from address 0x320000. I think thats how removed the "Z80 Error" message.

stay safe,

AamirM

> To answer my own question for anyone who's curious:
>
> The bios will be happy with just the Z80. No ym2610 is needed.
>
> > The neogeo bios does a test of the Z80, and hangs with an error message if the
> > Z80 behaves improperly.
> >
> > How much of the Z80 needs to be emulated to pass this test? Will the Z80 pass
> > on its own (with the ym2610 stubbed out), or does it need parts of the ym2610
> as
> > well?
> >
>



SubjectRe: NeoGeo bios z80 check Reply to this message
Posted bymasterzog
Posted on09/21/07 02:48 PM



Yeah that's how you trick the 68k into thinking the Z80 is there.

I'm trying to put the Z80 in for real now =)


> Hi,
>
> As far as I remember you need to return 1 when read from address 0x320000. I
> think thats how removed the "Z80 Error" message.
>
> stay safe,
>
> AamirM
>
> > To answer my own question for anyone who's curious:
> >
> > The bios will be happy with just the Z80. No ym2610 is needed.
> >
> > > The neogeo bios does a test of the Z80, and hangs with an error message if
> the
> > > Z80 behaves improperly.
> > >
> > > How much of the Z80 needs to be emulated to pass this test? Will the Z80
> pass
> > > on its own (with the ym2610 stubbed out), or does it need parts of the
> ym2610
> > as
> > > well?
> > >
> >
>





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