function to count bits with a mask for start and stop

2025-07-21 09:50:40 +02:00
parent a9dc588921
commit 10112332cc
1 changed files with 6 additions and 0 deletions
@@ -246,6 +246,12 @@ static __attribute__((always_inline)) inline int count_bits64(uint64_t v)
  return __builtin_popcountll(v);
 }

+static __attribute__((always_inline)) inline int count_bits64_with_mask(uint64_t v, int start, int num)
+{
+  uint64_t mask = ((1LL << num) - 1) << start;
+  return count_bits64(v & mask);
+}
+
 uint64_t reverse_bits(uint64_t in, int n_bits);
 void reverse_bits_u8(uint8_t const* in, size_t sz, uint8_t* out);