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Re: Ping: CRC32 documentation patch
- From: Eli Zaretskii <eliz at gnu dot org>
- To: jeremy dot bennett at embecosm dot com
- Cc: gdb-patches at sourceware dot org
- Date: Tue, 04 Aug 2009 21:20:34 +0300
- Subject: Re: Ping: CRC32 documentation patch
- References: <m363dh1yub.fsf@google.com> <200907242331.n6ONVqSl003646@greed.delorie.com> <m3k51xzjbq.fsf@google.com> <83fxcl4491.fsf@gnu.org> <4A6B5BDD.80602@vmware.com> <1249407367.3284.80.camel@thomas>
- Reply-to: Eli Zaretskii <eliz at gnu dot org>
> From: Jeremy Bennett <jeremy.bennett@embecosm.com>
> Date: Tue, 04 Aug 2009 18:36:07 +0100
>
> This patch clarifies how CRC is calculated in the GDB manual. I think it
> probably got lost in the rest of the discussion of CRC.
Yes, sorry.
> Any comments?
Some.
> +The CRC used in @code{.gnu_debuglink} is the CRC-32 defined in
> +IEEE 802.3 using the polynomial @math{x^{32} + x^{26} + x^{23} + x^{22}
> ++ x^{16} + x^{12} +x^{11} + x^{10} + x^8 + x^7 + x^5 + x^4 + x^2 + x +
> +1}. The function is computed byte at a time, taking the least
Would the polynomial look better, both in print and in on-line
versions of the manual, if you put it into a @quotation or a @display,
and break it into separate lines manually? I fear that leaving the
line-breaking job to makeinfo or even TeX could produce ugly results
beyond our control.
> +significant bit of each byte first. The initial pattern
> +@code{0xffffffff} is used, to ensure leading zeros affect the CRC and
> +the final result is inverted to ensure trailing zeros also affect the
> +CRC.
Please leave two spaces between sentences, not one (here and elsewhere
in the patch).
> +For a complete explanation the code for the function used in
> +@code{.gnu_debuglink} is given here.
I suggest to reword like this (avoiding passive tense):
To complete the description, we show below the code of the function
which produces the CRC used in @code{.gnu_debuglink}.
Okay with these corrections.
Thanks.