MOS Buffer numbers

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dominicbeesley
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MOS Buffer numbers

Post by dominicbeesley » Wed Jul 08, 2020 11:56 am

I'm slowly hacking away at getting the Paula/Blitter boards to work from BASIC and I'd like to make them work as closely as possible to the original SOUND system

To that end I think I'm going to add some extra input buffers by intercepting INSV/REMV/CNPV but I'm not sure what buffer numbers to use. My first instinct is to use &14-&17 to make it similar to the existing sound buffer numbers but I'm not convinced this is the best idea as these buffer numbers may have been used by other systems.

Is there a list of buffer numbers used by MOS/Risc OS etc to help me choose.

D

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Richard Russell
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Re: MOS Buffer numbers

Post by Richard Russell » Wed Jul 08, 2020 12:45 pm

dominicbeesley wrote:
Wed Jul 08, 2020 11:56 am
Is there a list of buffer numbers used by MOS/Risc OS etc to help me choose.
There's this, which suggests that buffer numbers greater than 9 are currently free. But I would recommend that you edit that page (it's a Wiki) to reserve and document any that you intend to allocate.

dominicbeesley
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Re: MOS Buffer numbers

Post by dominicbeesley » Wed Jul 08, 2020 4:01 pm

Thanks. I'll update the wiki when it's working.

I wound have thought there was more hardware and software that used the buffer system but maybe I'm wrong

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Richard Russell
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Re: MOS Buffer numbers

Post by Richard Russell » Wed Jul 08, 2020 4:39 pm

dominicbeesley wrote:
Wed Jul 08, 2020 4:01 pm
I wound have thought there was more hardware and software that used the buffer system but maybe I'm wrong
It's entirely possible. Although Jonathan's Wiki isn't an official repository for such things it's the closest we've got (as far as I know). If somebody has reserved a buffer number, but not registered it there, they have only themselves to blame if there's a later clash.

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helpful
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Re: MOS Buffer numbers

Post by helpful » Wed Jul 08, 2020 4:50 pm

This page on the RISC OS Open wiki still only goes up to 9 - https://www.riscosopen.org/wiki/documen ... %20Numbers
RISC OS User Group Of London - http://www.rougol.jellybaby.net/
RISC OS London Show - http://www.riscoslondonshow.co.uk/

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jgharston
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Re: MOS Buffer numbers

Post by jgharston » Wed Jul 08, 2020 5:39 pm

There's also the MIDI buffers (see ADVAL). I'll have to track down a source to cite for those, from memory I first scribbled those down when in Hong Kong.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.32
(C) Copyright J.G.Harston 1989,2005-2020
>_

dominicbeesley
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Re: MOS Buffer numbers

Post by dominicbeesley » Thu Jul 09, 2020 11:50 am

Thanks all,

If I get a chance (between my DIY tasks) this weekend I'll try and get a bit further. It's a shame if all the OS hooks don't work properly for the buffers idea as it will mean a lot of extra work (and mucking around with extended vectors or grabbing a page of workspace which I'd like to avoid) I'll have to have a proper poke in the MOS disassembly. The buffers idea is a good one, but if there are complications with the implementation that might explain the reason for it being less used by applications or ROMs than I'd initially expected.

D

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