[PATCH v3 02/16] bitops: Add parity16(), parity32(), and parity64() helpers
From: Kuan-Wei Chiu <visitorckw@gmail.com>
Date: 2025-03-06 16:26:17
Also in:
bpf, dri-devel, linux-media, linux-serial, linux-wireless, lkml, netdev
Subsystem:
bitops api, the rest · Maintainers:
Yury Norov, Linus Torvalds
Add parity16(), parity32(), and parity64() to compute the parity of 16-bit, 32-bit, and 64-bit values, respectively. Each function extends parity8() by XOR-ing upper and lower halves, reducing the input size progressively. Co-developed-by: Yu-Chun Lin <redacted> Signed-off-by: Yu-Chun Lin <redacted> Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> --- include/linux/bitops.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 44e5765b8bec..906757e1ddf8 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h@@ -260,6 +260,48 @@ static inline __attribute_const__ bool parity8(u8 val) return (0x6996 >> (val & 0xf)) & 1; } +/** + * parity16 - get the parity of an u16 value + * @val: the value to be examined + * + * Determine the parity of the u16 argument. + * + * Returns: + * false for even parity, true for odd parity + */ +static inline __attribute_const__ bool parity16(u16 val) +{ + return parity8(val ^ (val >> 8)); +} + +/** + * parity32 - get the parity of an u32 value + * @val: the value to be examined + * + * Determine the parity of the u32 argument. + * + * Returns: + * false for even parity, true for odd parity + */ +static inline __attribute_const__ bool parity32(u32 val) +{ + return parity16(val ^ (val >> 16)); +} + +/** + * parity64 - get the parity of an u64 value + * @val: the value to be examined + * + * Determine the parity of the u64 argument. + * + * Returns: + * false for even parity, true for odd parity + */ +static inline __attribute_const__ bool parity64(u64 val) +{ + return parity32(val ^ (val >> 32)); +} + /** * __ffs64 - find first set bit in a 64 bit word * @word: The 64 bit word
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2.34.1