fixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/35005?usp=email )

Change subject: core: add parity calculation functions for uint{32,16,8}_t ......................................................................

core: add parity calculation functions for uint{32,16,8}_t

Change-Id: I2d6265eac5ce062276a40f4968b129d8702c6117 --- M include/osmocom/core/bits.h 1 file changed, 48 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/05/35005/1

diff --git a/include/osmocom/core/bits.h b/include/osmocom/core/bits.h index b1b8040..4b80036 100644 --- a/include/osmocom/core/bits.h +++ b/include/osmocom/core/bits.h @@ -119,4 +119,43 @@ return (in << shift) | (in >> (16 - shift)); }

+/*! Calculate parity for the given 32-bit unsigned integer. + * \param[in] x a 32-bit unsigned integer. + * \returns 1 for even parity (even number of bits set to 1); + * 0 for odd parity (odd number of bits set to 1). */ +static inline uint8_t osmo_parity_u32(uint32_t x) +{ + x ^= x >> 16; + x ^= x >> 8; + x ^= x >> 4; + x ^= x >> 2; + x ^= x >> 1; + return (~x) & 1; +} + +/*! Calculate parity for the given 16-bit unsigned integer. + * \param[in] x a 16-bit unsigned integer. + * \returns 1 for even parity (even number of bits set to 1); + * 0 for odd parity (odd number of bits set to 1). */ +static inline uint8_t osmo_parity_u16(uint16_t x) +{ + x ^= x >> 8; + x ^= x >> 4; + x ^= x >> 2; + x ^= x >> 1; + return (~x) & 1; +} + +/*! Calculate parity for the given 8-bit unsigned integer. + * \param[in] x a 8-bit unsigned integer. + * \returns 1 for even parity (even number of bits set to 1); + * 0 for odd parity (odd number of bits set to 1). */ +static inline uint8_t osmo_parity_u8(uint8_t x) +{ + x ^= x >> 4; + x ^= x >> 2; + x ^= x >> 1; + return (~x) & 1; +} + /*! @} */