[Gllug] Atomic increment/decrement

[Jonathan Dye]

> -----Original Message-----
> From: Tethys [mailto:tet at accucard.com]
> Sent: 07 August 2002 14:46
> To: gllug at linux.co.uk
> Subject: Re: [Gllug] Atomic increment/decrement 
> 
> >The whole thing depended on an atomic cpu test-and-set 
> instruction and was
> >written in assembler.
> 
> Even that may not be enough. On the Amiga, the TAS instruction wasn't
> always atomic, and could be defeated by system DMA...

For it to work properly with dma around you usually have to do something
like lock the memory bus but you get the same problem with smp.  AFAICR the
amiga never had an smp version as I guess it would have been a problem then
too.

> Tet

JD

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