diff options
| -rw-r--r-- | src/util/bitset.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/src/util/bitset.h b/src/util/bitset.h index dd6656e1f42..edda9f3406f 100644 --- a/src/util/bitset.h +++ b/src/util/bitset.h @@ -105,6 +105,47 @@ __bitset_not(BITSET_WORD *x, unsigned n) #define BITSET_NOT(x) \ __bitset_not(x, ARRAY_SIZE(x)) +static inline void +__bitset_rotate_right(BITSET_WORD *x, unsigned amount, unsigned n) +{ + assert(amount < BITSET_WORDBITS); + + if (amount == 0) + return; + + for (unsigned i = 0; i < n - 1; i++) { + x[i] = (x[i] >> amount) | (x[i + 1] << (BITSET_WORDBITS - amount)); + } + + x[n - 1] = x[n - 1] >> amount; +} + +static inline void +__bitset_shr(BITSET_WORD *x, unsigned amount, unsigned n) +{ + const unsigned int words = amount / BITSET_WORDBITS; + + if (amount == 0) + return; + + if (words) { + unsigned i; + + for (i = 0; i < n - words; i++) + x[i] = x[i + words]; + + while (i < n) + x[i++] = 0; + + amount %= BITSET_WORDBITS; + } + + __bitset_rotate_right(x, amount, n); +} + +#define BITSET_SHR(x, n) \ + __bitset_shr(x, n, ARRAY_SIZE(x)); + /* bit range operations */ #define BITSET_TEST_RANGE(x, b, e) \ |