diff options
Diffstat (limited to 'Documentation/staging/crc32.rst')
| -rw-r--r-- | Documentation/staging/crc32.rst | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/staging/crc32.rst b/Documentation/staging/crc32.rst index 8a6860f33b4e..64f3dd430a6c 100644 --- a/Documentation/staging/crc32.rst +++ b/Documentation/staging/crc32.rst @@ -1,5 +1,5 @@ ================================= -brief tutorial on CRC computation +Brief tutorial on CRC computation ================================= A CRC is a long-division remainder. You add the CRC to the message, @@ -34,7 +34,7 @@ do it in the right order, matching the endianness. Just like with ordinary division, you proceed one digit (bit) at a time. Each step of the division you take one more digit (bit) of the dividend and append it to the current remainder. Then you figure out the -appropriate multiple of the divisor to subtract to being the remainder +appropriate multiple of the divisor to subtract to bring the remainder back into range. In binary, this is easy - it has to be either 0 or 1, and to make the XOR cancel, it's just a copy of bit 32 of the remainder. @@ -116,7 +116,7 @@ for any fractional bytes at the end. To reduce the number of conditional branches, software commonly uses the byte-at-a-time table method, popularized by Dilip V. Sarwate, "Computation of Cyclic Redundancy Checks via Table Look-Up", Comm. ACM -v.31 no.8 (August 1998) p. 1008-1013. +v.31 no.8 (August 1988) p. 1008-1013. Here, rather than just shifting one bit of the remainder to decide in the correct multiple to subtract, we can shift a byte at a time. |