int is_new_avx512()

in src/random/sampling_avx512.c [86:110]

• 14 lines of code
• 4 McCabe index (conditional complexity)

int is_new_avx512(IN const idx_t *wlist, IN const size_t ctr)
{
  bike_static_assert((sizeof(idx_t) == sizeof(uint32_t)), idx_t_is_not_uint32_t);

  REG_T idx_ctr = SET1_I32(wlist[ctr]);

  for(size_t i = 0; i < ctr; i += REG_DWORDS) {
    // Comparisons are done with SIMD instructions with each SIMD register
    // containing REG_DWORDS elements. We compare registers element-wise:
    // idx_ctr = {8 repetitions of wlist[ctr]}, with
    // idx_cur = {8 consecutive elements from wlist}.
    // In the last iteration we consider wlist elements only up to ctr.

    REG_T idx_cur = LOAD(&wlist[i]);

    uint16_t mask  = (ctr < (i + REG_DWORDS)) ? MASK(ctr - i) : 0xffff;
    uint16_t check = MCMPMEQ_I32(mask, idx_ctr, idx_cur);

    if(check != 0) {
      return 0;
    }
  }

  return 1;
}