static inline double inner_product_double()

in subprojects/speex/resample_sse.h [78:97]

• 19 lines of code
• 2 McCabe index (conditional complexity)

static inline double inner_product_double(const float *a, const float *b, unsigned int len)
{
   int i;
   double ret;
   __m128d sum = _mm_setzero_pd();
   __m128 t;
   for (i=0;i<len;i+=8)
   {
      t = _mm_mul_ps(_mm_loadu_ps(a+i), _mm_loadu_ps(b+i));
      sum = _mm_add_pd(sum, _mm_cvtps_pd(t));
      sum = _mm_add_pd(sum, _mm_cvtps_pd(_mm_movehl_ps(t, t)));

      t = _mm_mul_ps(_mm_loadu_ps(a+i+4), _mm_loadu_ps(b+i+4));
      sum = _mm_add_pd(sum, _mm_cvtps_pd(t));
      sum = _mm_add_pd(sum, _mm_cvtps_pd(_mm_movehl_ps(t, t)));
   }
   sum = _mm_add_sd(sum, _mm_unpackhi_pd(sum, sum));
   _mm_store_sd(&ret, sum);
   return ret;
}