text: #ifdef HAVE_SSE41
  /**
   * OpenAL cross platform audio library
   * Copyright (C) 2014 by Timothy Arceri <t_arceri@yahoo.com.au>.
   * This library is free software; you can redistribute it and/or
   *  modify it under the terms of the GNU Library General Public
   *  License as published by the Free Software Foundation; either
   *  version 2 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  Library General Public License for more details.
   *
   * You should have received a copy of the GNU Library General Public
   *  License along with this library; if not, write to the
   *  Free Software Foundation, Inc.,
   *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   * Or go to http://www.gnu.org/copyleft/lgpl.html
   */
  
  #include "config.h"
  
  #include <xmmintrin.h>
  #include <emmintrin.h>
  #include <smmintrin.h>
  
  #include "alu.h"
  #include "defs.h"
  
  
  template<>
  const ALfloat *Resample_<LerpTag,SSE4Tag>(const InterpState*, const ALfloat *RESTRICT src,
      ALsizei frac, ALint increment, ALfloat *RESTRICT dst, ALsizei dstlen)
  {
      const __m128i increment4{_mm_set1_epi32(increment*4)};
      const __m128 fracOne4{_mm_set1_ps(1.0f/FRACTIONONE)};
      const __m128i fracMask4{_mm_set1_epi32(FRACTIONMASK)};
  
      ASSUME(frac >= 0);
      ASSUME(increment > 0);
      ASSUME(dstlen >= 0);
  
      alignas(16) ALsizei pos_[4], frac_[4];
      InitiatePositionArrays(frac, increment, frac_, pos_, 4);
      __m128i frac4{_mm_setr_epi32(frac_[0], frac_[1], frac_[2], frac_[3])};
      __m128i pos4{_mm_setr_epi32(pos_[0], pos_[1], pos_[2], pos_[3])};
  
      const ALsizei todo{dstlen & ~3};
      for(ALsizei i{0};i < todo;i += 4)
      {
          const int pos0{_mm_extract_epi32(pos4, 0)};
          const int pos1{_mm_extract_epi32(pos4, 1)};
          const int pos2{_mm_extract_epi32(pos4, 2)};
          const int pos3{_mm_extract_epi32(pos4, 3)};
          const __m128 val1{_mm_setr_ps(src[pos0  ], src[pos1  ], src[pos2  ], src[pos3  ])};
          const __m128 val2{_mm_setr_ps(src[pos0+1], src[pos1+1], src[pos2+1], src[pos3+1])};
  
          /* val1 + (val2-val1)*mu */
          const __m128 r0{_mm_sub_ps(val2, val1)};
          const __m128 mu{_mm_mul_ps(_mm_cvtepi32_ps(frac4), fracOne4)};
          const __m128 out{_mm_add_ps(val1, _mm_mul_ps(mu, r0))};
  
          _mm_store_ps(&dst[i], out);
  
          frac4 = _mm_add_epi32(frac4, increment4);
          pos4 = _mm_add_epi32(pos4, _mm_srli_epi32(frac4, FRACTIONBITS));
          frac4 = _mm_and_si128(frac4, fracMask4);
      }
  
      /* NOTE: These four elements represent the position *after* the last four
       * samples, so the lowest element is the next position to resample.
       */
      ALsizei pos{_mm_cvtsi128_si32(pos4)};
      frac = _mm_cvtsi128_si32(frac4);
  
      for(ALsizei i{todo};i < dstlen;++i)
      {
          dst[i] = lerp(src[pos], src[pos+1], frac * (1.0f/FRACTIONONE));
  
          frac += increment;
          pos  += frac>>FRACTIONBITS;
          frac &= FRACTIONMASK;
      }
      return dst;
  }
  
  #endif