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Re: ISR interrupts latency time
- To: Nicpoñ Marcin <nicpon at rts dot com dot pl>
- Subject: Re: [ECOS] ISR interrupts latency time
- From: Jesper Skov <jskov at cambridge dot redhat dot com>
- Date: 08 Jun 2001 10:38:09 +0200
- Cc: <ecos-discuss at sources dot redhat dot com>
- References: <006701c0eff2$5faa3c10$2e00a8c0@rts.com.pl>
>>>>> "Nicpoñ" == Nicpoñ Marcin <nicpon@rts.com.pl> writes:
Nicpoñ> I`ve a problem with interrupts.I`m working on Motorola PPC850
Nicpoñ> and I measured (interrupt) ISR handling latency time and it
Nicpoñ> was very long. If I write handling funcion in assembler file
Nicpoñ> (vectors.S) I`ve got a tomes 10X shorter than default handlig
Nicpoñ> so the problem is between starting assembler handling function
Nicpoñ> and C handling function, which I defined in
Nicpoñ> cyg_interrupt_create(), but I can`t find in which part of code
Nicpoñ> take so long time. Which function (macro) I should correct to
Nicpoñ> faster intrrupt handling ?
Not understood - the present VSR is already written in assembly
(cyg_hal_default_interrupt_vsr) which is what calls the ISR.
A possible exception is if the interrupt in question is one of those
handled via the arbitration code in mpc8xx var_intr.c. In that case
you could rewrite the C functions in assembly. But I doubt there'd be
many cycles saved.
Jesper