#ifndef CKB_C_STDLIB_INTERNAL_ATOMIC_H_
#define CKB_C_STDLIB_INTERNAL_ATOMIC_H_
#include <internal/types.h>

/*
 * Modified from
 * https://git.musl-libc.org/cgit/musl/tree/src/internal/atomic.h?id=33338ebc853d37c80f0f236cc7a92cb0acc6aace
 */
static inline int a_ctz_32(uint32_t x) {
  static const char debruijn32[32] = {
      0,  1,  23, 2,  29, 24, 19, 3,  30, 27, 25, 11, 20, 8, 4,  13,
      31, 22, 28, 18, 26, 10, 7,  12, 21, 17, 9,  6,  16, 5, 15, 14};
  return debruijn32[(x & -x) * 0x076be629 >> 27];
}

static inline int a_ctz_64(uint64_t x) {
  static const char debruijn64[64] = {
      0,  1,  2,  53, 3,  7,  54, 27, 4,  38, 41, 8,  34, 55, 48, 28,
      62, 5,  39, 46, 44, 42, 22, 9,  24, 35, 59, 56, 49, 18, 29, 11,
      63, 52, 6,  26, 37, 40, 33, 47, 61, 45, 43, 21, 23, 58, 17, 10,
      51, 25, 36, 32, 60, 20, 57, 16, 50, 31, 19, 15, 30, 14, 13, 12};
  if (sizeof(long) < 8) {
    uint32_t y = x;
    if (!y) {
      y = x >> 32;
      return 32 + a_ctz_32(y);
    }
    return a_ctz_32(y);
  }
  return debruijn64[(x & -x) * 0x022fdd63cc95386dull >> 58];
}

static inline int a_ctz_l(unsigned long x) {
  return (sizeof(long) < 8) ? a_ctz_32(x) : a_ctz_64(x);
}

#endif /* CKB_C_STDLIB_INTERNAL_ATOMIC_H_ */