Date   : Fri, 08 May 2009 17:50:03 +0200
From   : kortink@... (John Kortink)
Subject: ReCo6502 now available

On 08 May 2009 10:35:54 +0100, jgh@... (Jonathan Graham
Harston) wrote:

>> Message-ID: <r8r6051nmnfqaias0i0kfqo6s07747dkp4@...>
> 
>John Kortink wrote:
>> ReCo6502 now available
> 
>While perusing the ReCo6502 documentation I started thinking about
>the possibility of being able to do data transfer to the flat 65816
>memory model, ie to be able to *LOAD or *SAVE anywhere in the 512K
>using "normal" addresses, not having to page banks in and do a
>chunk at a a time.

Only the Tube OS need a few slight changes, to deal with
transfers larger than 64 K.

>I realised I was rethinking the same thoughts I'd had about flat
>memory access for my PDP-11 system.
> 
>If no memory paging has occured, then *LOADing to &0000xxxx would
>load data to memory at &0000xxxx, just as with the 6502 Tube client
>MOS. However, if a bank has been paged (eg bank 4 paged in at
>&4000) and 64K of data is LOADed to &00000000, then that data will
>be loaded to &000000-&003FFF, &010000-&013FFFF, &008000-&00FFFF.
> 
>That's ok

It's not ok. Only 'bank 0' ought to appear in such transfers.
Not the bank that happens to be selected at the time. That is
what causes the inconsistency. I.e. banks other than '0' should
require special addressing. Or none at all.

>[...]


John Kortink

-- 

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