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MINOR: tools: add 64-bit rotate operators

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This adds rotl64/rotr64 to rotate a 64-bit word by an arbitrary number
of bits. It's mainly aimed at being used with constants.
This commit is contained in:
Willy Tarreau 2020-03-08 00:41:00 +01:00
parent f726e03bb8
commit 7a40909c00
1 changed files with 20 additions and 0 deletions
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20
include/common/standard.h
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@ -66,6 +66,26 @@
* power of 2, and 0 otherwise */
#define POWEROF2(x) (((x) & ((x)-1)) == 0)
/* rotate left a 64-bit integer by <bits:[0-5]> bits */
static inline uint64_t rotl64(uint64_t v, uint8_t bits)
{
#if !defined(__ARM_ARCH_8A) && !defined(__x86_64__)
bits &= 63;
#endif
v = (v << bits) | (v >> (-bits & 63));
return v;
}
/* rotate right a 64-bit integer by <bits:[0-5]> bits */
static inline uint64_t rotr64(uint64_t v, uint8_t bits)
{
#if !defined(__ARM_ARCH_8A) && !defined(__x86_64__)
bits &= 63;
#endif
v = (v >> bits) | (v << (-bits & 63));
return v;
}
/* DEFNULL() returns either the argument as-is, or NULL if absent. This is for
* use in macros arguments.
*/