Date   : Mon, 30 Nov 2009 01:58:35 +0100
From   : kortink@... (John Kortink)
Subject: Tube - I/O processor memory questions

On Sun, 29 Nov 2009 23:42:06 +0000, Kevin Bracey
<kevin@...> wrote:

>John Kortink wrote:
>> On Sun, 29 Nov 2009 22:06:25 +0000, Kevin Bracey
>> <kevin@...> wrote:
>>
>>   
>>> John Kortink wrote:
>>>
>>>     
>>> Actually, you also get &90-&EE allocated to you
>>>     
>>
>> They're not being used on a standard 6502 2p
>> running Tube OS 1.10. But that doesn't mean
>> they're not reserved for future use.
>>   
>Well, they are explicitly documented as being available to languages in 
>the original 6502 Second Processor User Guide:
>
>    Page 0 to &EE is available
>    Page 1 = stack
>    Page 2 = OS indirections and user memory
>    Page 3 = error messages
>    Page 4 ? 7 are available to the user, although not in BASIC
>    Page 8 ? &F7 available to the user
>
>
>That's sounds like official documentation, not just some bit of 
>reverse-engineering.

It sounds very much like reverse engineering to me.

Not least because at this moment I happen to be right
in the middle of heavily tweaking Tube OS 1.10 for my
own creation ReCo6502, which is why I know that those
allocations are not entirely correct. In reality, error
messages are copied to &236-&2FF, i.e. there is no user
memory in page 2. And page 3 is not used at all ...

>[...]
>
>On the other hand, it seems that Acorn may have been over-generous by 
>not leaving themselves any slack for future expansion in those docs.

Well, that's a given ... Therefore clearly not to be
understood as official allocations, but rather as a
description of what happened to be unused (as opposed
to free) memory at that point, for that particular
copro, and that particular Tube OS.

>[...]


John Kortink

-- 

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