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| author |   Roger Knecht <roger@norberthealth.com> | 2022-05-21 14:47:45 +0200 |
|---|---|---|
| committer |   Jason A. Donenfeld <Jason@zx2c4.com> | 2022-06-07 10:27:38 +0200 |
| commit | 77991645952c21962a095910c51fe0f73d35bf91 (patch) | |
| tree | 390109e8afbf963abde0928317275fefb85c58db /lib | |
| parent | Merge tag 'dma-mapping-5.19-2022-06-06' of git://git.infradead.org/users/hch/dma-mapping (diff) | |
| download | linux-dev-77991645952c21962a095910c51fe0f73d35bf91.tar.xz linux-dev-77991645952c21962a095910c51fe0f73d35bf91.zip | |
crc-itu-t: fix typo in CRC ITU-T polynomial comment
The code comment says that the polynomial is x^16 + x^12 + x^15 + 1, but
the correct polynomial is x^16 + x^12 + x^5 + 1. Quoting from page 2 in
the ITU-T V.41 specification [1]:
2 Encoding and checking process
The service bits and information bits, taken in conjunction,
correspond to the coefficients of a message polynomial having terms
from x^(n-1) (n = total number of bits in a block or sequence) down to
x^16. This polynomial is divided, modulo 2, by the generating
polynomial x^16 + x^12 + x^5 + 1.
The hex (truncated) polynomial 0x1021 and CRC code implementation are
correct, however.
[1] https://www.itu.int/rec/T-REC-V.41-198811-I/en
Signed-off-by: Roger Knecht <roger@norberthealth.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/crc-itu-t.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/crc-itu-t.c b/lib/crc-itu-t.c index 1974b355c148..1d26a1647da5 100644 --- a/lib/crc-itu-t.c +++ b/lib/crc-itu-t.c @@ -7,7 +7,7 @@ #include <linux/module.h> #include <linux/crc-itu-t.h> -/** CRC table for the CRC ITU-T V.41 0x1021 (x^16 + x^12 + x^15 + 1) */ +/* CRC table for the CRC ITU-T V.41 0x1021 (x^16 + x^12 + x^5 + 1) */ const u16 crc_itu_t_table[256] = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, |