From: Gary Thomas <gary@mlbassoc.com>
To: osv <osv@javad.com>
Cc: eCos Discussion <ecos-discuss@ecos.sourceware.org>
Subject: Re: [ECOS] CYG_ISR_CALL_DSR vs CYG_ISR_HANDLED
Date: Fri, 18 Nov 2005 14:12:00 -0000 [thread overview]
Message-ID: <1132323138.5138.207.camel@hermes> (raw)
In-Reply-To: <87veyqgipi.fsf@javad.com>
On Fri, 2005-11-18 at 16:59 +0300, osv wrote:
> Hello,
>
> In the eCos reference manual one can read:
>
> The return value of an ISR is normally one of CYG_ISR_CALL_DSR or
> CYG_ISR_HANDLED. The former indicates that further processing is
> required at DSR level, and the interrupt handlerĆæs DSR will be run as
> soon as possible. The latter indicates that the interrupt has been
> fully handled and no further effort is required.
This is poorly worded I think.
>
> However, the eCos internal clock isr (Cyg_RealTimeClock::isr()) returns
> as follows:
>
> return Cyg_Interrupt::CALL_DSR|Cyg_Interrupt::HANDLED;
>
> that seems to contradict with the description above. What is the truth
> about isr handler return codes?
CYG_ISR_HANDLED says that the ISR actually did something about the
interrupt. It's used by chained interrupts to determine if another
ISR (which shares the same interrupt) should be run.
CYG_ISR_CALL_DSR indicates that the DSR which corresponds to this ISR
should be run.
These are bit values which can be successfully or'ed together to achieve
the desired result.
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
--
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next prev parent reply other threads:[~2005-11-18 14:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-18 13:59 osv
2005-11-18 14:12 ` Gary Thomas [this message]
2005-11-23 19:06 ` [ECOS] [PATCH] " osv
2006-04-04 4:23 ` [ECOS] Informal eCos gathering at the San Jose Embedded Systems Conference this Wednesday! Andrew Greenberg
2006-04-04 4:23 ` Andrew Greenberg
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