lkml.org 
[lkml]   [2007]   [May]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/6] firewire: handling of cards, buses, nodes
Pekka Enberg wrote:
> On 5/2/07, Stefan Richter <stefanr@s5r6.in-berlin.de> wrote:
>> +/* The lib/crc16.c implementation uses the standard (0x8005)
>> + * polynomial, but we need the ITU-T (or CCITT) polynomial (0x1021).
>> + * The implementation below works on an array of host-endian u32
>> + * words, assuming they'll be transmited msb first. */
>> +u16
>> +crc16_itu_t(const u32 *buffer, size_t length)
>> +{
>
> [snip]
>
> So put it in lib/crc-itu-t.c? Btw, there's apparently another ITU-T
> implementation floating around by Ivo van Doorn.

I looked around a bit with grep -R and a few search terms but didn't
find something definite. Is there any other user of a crc16_itu_t or
crc_ccitt or whatever which operates on a (CPU byte ordered) u32[]
instead of on a (network byte ordered) u8[]?

The only value in having a shared implementation would be a potentially
smaller kernel. Sharing it to ensure correctness is not an issue;
fw-topology.c::crc16_itu_t is simply the one in IEEE 1212 table 5.
Performance is also not an issue (if better algorithms exist) because
the FireWire stack uses it only infrequently on a moderate amount of data.
--
Stefan Richter
-=====-=-=== -=-= ---=-
http://arcgraph.de/sr/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-02 21:19    [W:0.704 / U:0.308 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site