ARM and Fast Interrupts

[xu ray]

It would be nice to support FIQ for ARM. It can improve ARM
performance in some cases.
Just beware of the following issues:
(1)The FIQ is disabled by default. _CPU_ISR_Disable and
_CPU_ISR_Enable is by default disable both FIQ and IRQ in the same
time. Will you add a new API for FIQ?
(2)FIQ has higher priority than IRQ, so it is dangerous to use it
excessively sometimes. It would be better put some warning in the code
in case programmers make mistakes.
(3) Update the CPU supplement manual for ARM if necessary

2009/4/29 Sebastian Huber <sebastian.huber at embedded-brains.de>:
> Hi,
>
> currently fast interrupts (FIQ) are disabled during rtems_interrupt_disable()
> and rtems_interrupt_enable().  This makes them pretty useless since all their
> benefits are wiped out.  If someone really needs operating system support for
> FIQs he can trigger a software interrupt inside the FIQ handler which does this
> job.  I want to change the interrupt disable mask such that FIQs are not
> disabled during rtems_interrupt_disable() and rtems_interrupt_enable().  Any
> objections?
>
> Have a nice day!
>
> --
> Sebastian Huber, Embedded Brains GmbH
>
> Address : Obere Lagerstr. 30, D-82178 Puchheim, Germany
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> E-Mail  : sebastian.huber at embedded-brains.de
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>
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-- 
Thanks & Best Regards!

Ray, Xu