//
// arch/x86_64/rsp/vmulh.h
//
// This file is subject to the terms and conditions defined in
// 'LICENSE', which is part of this source code package.
//

template <bool VMADH>
static inline __m128i rsp_vmadh_vmudh(__m128i vs, __m128i vt,
  __m128i zero, __m128i *acc_lo, __m128i *acc_md, __m128i *acc_hi) {
  __m128i lo, hi, overflow_mask;

  lo = _mm_mullo_epi16(vs, vt); 
  hi = _mm_mulhi_epi16(vs, vt); 

  // VMADH
  if (VMADH) {
    // Tricky part: start accumulate everything.
    // Get/keep the carry as we'll add it in later.
    overflow_mask = _mm_adds_epu16(*acc_md, lo); 
    *acc_md = _mm_add_epi16(*acc_md, lo); 

    overflow_mask = _mm_cmpeq_epi16(*acc_md, overflow_mask);
    overflow_mask = _mm_cmpeq_epi16(overflow_mask, zero);

    hi = _mm_sub_epi16(hi, overflow_mask); 
    *acc_hi = _mm_add_epi16(*acc_hi, hi);
  }

  // VMUDH
  else {
    *acc_lo = zero;
    *acc_md = lo;
    *acc_hi = hi;
  }

  return rsp_sclamp_acc_tomd(*acc_md, *acc_hi);
}

