Re: About gcc builtin atomics
On Tue, Jun 26, 2012 at 10:26 AM, Thorsten Glaser <tg@mirbsd.de> wrote:
> Geert Uytterhoeven dixit:
>
>>Even if they're fixed on ARAnyM, this doesn't fix the CAS problems on several
>>instantations of real hardware....
>
> Right. That’s why we use the syscall always. OK.
> (On Linux, but not on e.g. FreeMiNT.)
FreeMiNT on which hardware?
arch/m68k/Kconfig.cpu has:
config RMW_INSNS
bool "Use read-modify-write instructions"
depends on ADVANCED
---help---
This allows to use certain instructions that work with indivisible
read-modify-write bus cycles. While this is faster than the
workaround of disabling interrupts, it can conflict with DMA
( = direct memory access) on many Amiga systems, and it is also said
to destabilize other machines. It is very likely that this will
cause serious problems on any Amiga or Atari Medusa if set. The only
configuration where it should work are 68030-based Ataris, where it
apparently improves performance. But you've been warned! Unless you
really know what you are doing, say N. Try Y only if you're quite
adventurous.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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