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| author | Jani Nikula <jani.nikula@intel.com> | 2025-02-05 19:12:37 +0200 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2025-02-05 19:12:37 +0200 |
| commit | ea9f8f2b21795a5d80418a655bcb212d5b89e08f (patch) | |
| tree | 16190fb8cb798e7643667784b5a85f60de1f755e /include/linux/bitops.h | |
| parent | bdcdb913c2d36447ea49d33774e5d6093c55d6f7 (diff) | |
| parent | 2014c95afecee3e76ca4a56956a936e23283f05b (diff) | |
Merge drm/drm-next into drm-intel-next
Sync with v6.14-rc1.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'include/linux/bitops.h')
| -rw-r--r-- | include/linux/bitops.h | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index ba35bbf07798..c1cb53cf2f0f 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -230,6 +230,37 @@ static inline int get_count_order_long(unsigned long l) } /** + * parity8 - get the parity of an u8 value + * @value: the value to be examined + * + * Determine the parity of the u8 argument. + * + * Returns: + * 0 for even parity, 1 for odd parity + * + * Note: This function informs you about the current parity. Example to bail + * out when parity is odd: + * + * if (parity8(val) == 1) + * return -EBADMSG; + * + * If you need to calculate a parity bit, you need to draw the conclusion from + * this result yourself. Example to enforce odd parity, parity bit is bit 7: + * + * if (parity8(val) == 0) + * val ^= BIT(7); + */ +static inline int parity8(u8 val) +{ + /* + * One explanation of this algorithm: + * https://funloop.org/codex/problem/parity/README.html + */ + val ^= val >> 4; + return (0x6996 >> (val & 0xf)) & 1; +} + +/** * __ffs64 - find first set bit in a 64 bit word * @word: The 64 bit word * |
