Subject:
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Re: LegOS 0.2.5 and LNP
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Sun, 21 Jan 2001 15:36:09 GMT
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Viewed:
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1294 times
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"Paolo Masetti" <paolom@pragmanet.it> writes:
> I think that we can use safely (CONF_TM || defined CONF_HOST)
> condition.
>
> I'm checking the whole patch and I think that it could be
> realeased soon.
Ok. Checking and testing never hurts :-).
> I'm just wondering:
>
> 1) Why have you used
>
> + lnp_integrity_handler_t intgh;
> + lnp_addressing_handler_t addrh;
>
> in lnp_receive_packet(), apart from a very little optimization or
> something I can't see? :-)
It's not for performance, but for correctness. The old code was like this:
if(lnp_addressing_handler[port]) {
...
lnp_addressing_handler[port](data,length-2,src);
You first test lnp_integrity_handler and then, before using it, you reload
it from memory. If the value has changed (and it could on a PC, as you are
not in an interrupt handler) you have problems. The right thing is to read
once and use twice. Probably if there are no function calls in place of
"..." (but in 0.2.5 there may be one) the compiler will optimize it and
read only once, but it's better to force the compiler to do what you want
with actual code. For the same reason I added the volatile attribute.
> 2) I can see that you do not have any sem_destroy() for buf_sem,
> so I will probably introduce a lnp_shutdown() function that will
> to destroy it. That function wasn't required before buf_sem
> introduction.
Good idea. Lacking of sem_destroy() causes no trouble on many platforms,
as it does nothing, but it's better to be on the safe side.
bye
Bernardo
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Message has 1 Reply:
 | | Re: LegOS 0.2.5 and LNP
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| (...) was like this: (...) you reload (...) PC, as you are (...) thing is to read (...) place of (...) optimize it and (...) what you want (...) attribute. Yes, but I'm not sure what could happen if I change those addresses in the middle of the (...) (24 years ago, 22-Jan-01, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Re: LegOS 0.2.5 and LNP
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| (...) you may see (...) give access (...) the handlers (...) My only (...) depend on. (...) introduce a (...) this point to (...) I think that we can use safely (CONF_TM || defined CONF_HOST) condition. I'm checking the whole patch and I think that (...) (24 years ago, 21-Jan-01, to lugnet.robotics.rcx.legos)
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