summaryrefslogtreecommitdiff
path: root/lib/crc-itu-t.c
diff options
context:
space:
mode:
authorRoger Knecht <roger@norberthealth.com>2022-05-21 14:47:45 +0200
committerJason A. Donenfeld <Jason@zx2c4.com>2022-06-07 10:27:38 +0200
commit77991645952c21962a095910c51fe0f73d35bf91 (patch)
tree390109e8afbf963abde0928317275fefb85c58db /lib/crc-itu-t.c
parente71e60cd74df9386c3f684c54888f2367050b831 (diff)
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/crc-itu-t.c')
-rw-r--r--lib/crc-itu-t.c2
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,