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SubjectRe: Memory corruption in 8390.c ?
Date
Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

> Ar Mer, 2006-06-21 am 10:23 -0700, ysgrifennodd Ben Pfaff:
>> > + memset(buf, 0, ETH_ZLEN); /* more efficient than doing just the needed bits */
>> > + memcpy(buf, data, ETH_ZLEN);
>>
>> Is this really correct? It zeros out ETH_ZLEN bytes only to
>> immediately copy over all of them again.
>
> When I did it originally I tested with rdtsc and its actually quicker to
> let it build the static memset the copy data over it than to do the
> extra maths and the variable length loop.
>
> Hence the comment

You are saying that this:
memset(buf, 0, ETH_ZLEN);
memcpy(buf, data, ETH_ZLEN);
is faster than this?
memcpy(buf, data, ETH_ZLEN);

Because as far as I can tell they are equivalent.
--
Ben Pfaff
email: blp@cs.stanford.edu
web: http://benpfaff.org
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