| /* | 
 |  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. | 
 |  * | 
 |  *  Use of this source code is governed by a BSD-style license | 
 |  *  that can be found in the LICENSE file in the root of the source | 
 |  *  tree. An additional intellectual property rights grant can be found | 
 |  *  in the file PATENTS.  All contributing project authors may | 
 |  *  be found in the AUTHORS file in the root of the source tree. | 
 |  */ | 
 |  | 
 | #include <emmintrin.h> | 
 | #include <xmmintrin.h> | 
 |  | 
 | #include "modules/audio_processing/utility/ooura_fft.h" | 
 | #include "modules/audio_processing/utility/ooura_fft_tables_common.h" | 
 | #include "modules/audio_processing/utility/ooura_fft_tables_neon_sse2.h" | 
 | #include "rtc_base/system/arch.h" | 
 |  | 
 | namespace webrtc { | 
 |  | 
 | #if defined(WEBRTC_ARCH_X86_FAMILY) | 
 |  | 
 | namespace { | 
 | // These intrinsics were unavailable before VS 2008. | 
 | // TODO(andrew): move to a common file. | 
 | #if defined(_MSC_VER) && _MSC_VER < 1500 | 
 | static __inline __m128 _mm_castsi128_ps(__m128i a) { | 
 |   return *(__m128*)&a; | 
 | } | 
 | static __inline __m128i _mm_castps_si128(__m128 a) { | 
 |   return *(__m128i*)&a; | 
 | } | 
 | #endif | 
 |  | 
 | }  // namespace | 
 |  | 
 | void cft1st_128_SSE2(float* a) { | 
 |   const __m128 mm_swap_sign = _mm_load_ps(k_swap_sign); | 
 |   int j, k2; | 
 |  | 
 |   for (k2 = 0, j = 0; j < 128; j += 16, k2 += 4) { | 
 |     __m128 a00v = _mm_loadu_ps(&a[j + 0]); | 
 |     __m128 a04v = _mm_loadu_ps(&a[j + 4]); | 
 |     __m128 a08v = _mm_loadu_ps(&a[j + 8]); | 
 |     __m128 a12v = _mm_loadu_ps(&a[j + 12]); | 
 |     __m128 a01v = _mm_shuffle_ps(a00v, a08v, _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     __m128 a23v = _mm_shuffle_ps(a00v, a08v, _MM_SHUFFLE(3, 2, 3, 2)); | 
 |     __m128 a45v = _mm_shuffle_ps(a04v, a12v, _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     __m128 a67v = _mm_shuffle_ps(a04v, a12v, _MM_SHUFFLE(3, 2, 3, 2)); | 
 |  | 
 |     const __m128 wk1rv = _mm_load_ps(&rdft_wk1r[k2]); | 
 |     const __m128 wk1iv = _mm_load_ps(&rdft_wk1i[k2]); | 
 |     const __m128 wk2rv = _mm_load_ps(&rdft_wk2r[k2]); | 
 |     const __m128 wk2iv = _mm_load_ps(&rdft_wk2i[k2]); | 
 |     const __m128 wk3rv = _mm_load_ps(&rdft_wk3r[k2]); | 
 |     const __m128 wk3iv = _mm_load_ps(&rdft_wk3i[k2]); | 
 |     __m128 x0v = _mm_add_ps(a01v, a23v); | 
 |     const __m128 x1v = _mm_sub_ps(a01v, a23v); | 
 |     const __m128 x2v = _mm_add_ps(a45v, a67v); | 
 |     const __m128 x3v = _mm_sub_ps(a45v, a67v); | 
 |     __m128 x0w; | 
 |     a01v = _mm_add_ps(x0v, x2v); | 
 |     x0v = _mm_sub_ps(x0v, x2v); | 
 |     x0w = _mm_shuffle_ps(x0v, x0v, _MM_SHUFFLE(2, 3, 0, 1)); | 
 |     { | 
 |       const __m128 a45_0v = _mm_mul_ps(wk2rv, x0v); | 
 |       const __m128 a45_1v = _mm_mul_ps(wk2iv, x0w); | 
 |       a45v = _mm_add_ps(a45_0v, a45_1v); | 
 |     } | 
 |     { | 
 |       __m128 a23_0v, a23_1v; | 
 |       const __m128 x3w = _mm_shuffle_ps(x3v, x3v, _MM_SHUFFLE(2, 3, 0, 1)); | 
 |       const __m128 x3s = _mm_mul_ps(mm_swap_sign, x3w); | 
 |       x0v = _mm_add_ps(x1v, x3s); | 
 |       x0w = _mm_shuffle_ps(x0v, x0v, _MM_SHUFFLE(2, 3, 0, 1)); | 
 |       a23_0v = _mm_mul_ps(wk1rv, x0v); | 
 |       a23_1v = _mm_mul_ps(wk1iv, x0w); | 
 |       a23v = _mm_add_ps(a23_0v, a23_1v); | 
 |  | 
 |       x0v = _mm_sub_ps(x1v, x3s); | 
 |       x0w = _mm_shuffle_ps(x0v, x0v, _MM_SHUFFLE(2, 3, 0, 1)); | 
 |     } | 
 |     { | 
 |       const __m128 a67_0v = _mm_mul_ps(wk3rv, x0v); | 
 |       const __m128 a67_1v = _mm_mul_ps(wk3iv, x0w); | 
 |       a67v = _mm_add_ps(a67_0v, a67_1v); | 
 |     } | 
 |  | 
 |     a00v = _mm_shuffle_ps(a01v, a23v, _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     a04v = _mm_shuffle_ps(a45v, a67v, _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     a08v = _mm_shuffle_ps(a01v, a23v, _MM_SHUFFLE(3, 2, 3, 2)); | 
 |     a12v = _mm_shuffle_ps(a45v, a67v, _MM_SHUFFLE(3, 2, 3, 2)); | 
 |     _mm_storeu_ps(&a[j + 0], a00v); | 
 |     _mm_storeu_ps(&a[j + 4], a04v); | 
 |     _mm_storeu_ps(&a[j + 8], a08v); | 
 |     _mm_storeu_ps(&a[j + 12], a12v); | 
 |   } | 
 | } | 
 |  | 
 | void cftmdl_128_SSE2(float* a) { | 
 |   const int l = 8; | 
 |   const __m128 mm_swap_sign = _mm_load_ps(k_swap_sign); | 
 |   int j0; | 
 |  | 
 |   __m128 wk1rv = _mm_load_ps(cftmdl_wk1r); | 
 |   for (j0 = 0; j0 < l; j0 += 2) { | 
 |     const __m128i a_00 = _mm_loadl_epi64((__m128i*)&a[j0 + 0]); | 
 |     const __m128i a_08 = _mm_loadl_epi64((__m128i*)&a[j0 + 8]); | 
 |     const __m128i a_32 = _mm_loadl_epi64((__m128i*)&a[j0 + 32]); | 
 |     const __m128i a_40 = _mm_loadl_epi64((__m128i*)&a[j0 + 40]); | 
 |     const __m128 a_00_32 = | 
 |         _mm_shuffle_ps(_mm_castsi128_ps(a_00), _mm_castsi128_ps(a_32), | 
 |                        _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     const __m128 a_08_40 = | 
 |         _mm_shuffle_ps(_mm_castsi128_ps(a_08), _mm_castsi128_ps(a_40), | 
 |                        _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     __m128 x0r0_0i0_0r1_x0i1 = _mm_add_ps(a_00_32, a_08_40); | 
 |     const __m128 x1r0_1i0_1r1_x1i1 = _mm_sub_ps(a_00_32, a_08_40); | 
 |  | 
 |     const __m128i a_16 = _mm_loadl_epi64((__m128i*)&a[j0 + 16]); | 
 |     const __m128i a_24 = _mm_loadl_epi64((__m128i*)&a[j0 + 24]); | 
 |     const __m128i a_48 = _mm_loadl_epi64((__m128i*)&a[j0 + 48]); | 
 |     const __m128i a_56 = _mm_loadl_epi64((__m128i*)&a[j0 + 56]); | 
 |     const __m128 a_16_48 = | 
 |         _mm_shuffle_ps(_mm_castsi128_ps(a_16), _mm_castsi128_ps(a_48), | 
 |                        _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     const __m128 a_24_56 = | 
 |         _mm_shuffle_ps(_mm_castsi128_ps(a_24), _mm_castsi128_ps(a_56), | 
 |                        _MM_SHUFFLE(1, 0, 1, 0)); | 
 |     const __m128 x2r0_2i0_2r1_x2i1 = _mm_add_ps(a_16_48, a_24_56); | 
 |     const __m128 x3r0_3i0_3r1_x3i1 = _mm_sub_ps(a_16_48, a_24_56); | 
 |  | 
 |     const __m128 xx0 = _mm_add_ps(x0r0_0i0_0r1_x0i1, x2r0_2i0_2r1_x2i1); | 
 |     const __m128 xx1 = _mm_sub_ps(x0r0_0i0_0r1_x0i1, x2r0_2i0_2r1_x2i1); | 
 |  | 
 |     const __m128 x3i0_3r0_3i1_x3r1 = _mm_castsi128_ps(_mm_shuffle_epi32( | 
 |         _mm_castps_si128(x3r0_3i0_3r1_x3i1), _MM_SHUFFLE(2, 3, 0, 1))); | 
 |     const __m128 x3_swapped = _mm_mul_ps(mm_swap_sign, x3i0_3r0_3i1_x3r1); | 
 |     const __m128 x1_x3_add = _mm_add_ps(x1r0_1i0_1r1_x1i1, x3_swapped); | 
 |     const __m128 x1_x3_sub = _mm_sub_ps(x1r0_1i0_1r1_x1i1, x3_swapped); | 
 |  | 
 |     const __m128 yy0 = | 
 |         _mm_shuffle_ps(x1_x3_add, x1_x3_sub, _MM_SHUFFLE(2, 2, 2, 2)); | 
 |     const __m128 yy1 = | 
 |         _mm_shuffle_ps(x1_x3_add, x1_x3_sub, _MM_SHUFFLE(3, 3, 3, 3)); | 
 |     const __m128 yy2 = _mm_mul_ps(mm_swap_sign, yy1); | 
 |     const __m128 yy3 = _mm_add_ps(yy0, yy2); | 
 |     const __m128 yy4 = _mm_mul_ps(wk1rv, yy3); | 
 |  | 
 |     _mm_storel_epi64((__m128i*)&a[j0 + 0], _mm_castps_si128(xx0)); | 
 |     _mm_storel_epi64( | 
 |         (__m128i*)&a[j0 + 32], | 
 |         _mm_shuffle_epi32(_mm_castps_si128(xx0), _MM_SHUFFLE(3, 2, 3, 2))); | 
 |  | 
 |     _mm_storel_epi64((__m128i*)&a[j0 + 16], _mm_castps_si128(xx1)); | 
 |     _mm_storel_epi64( | 
 |         (__m128i*)&a[j0 + 48], | 
 |         _mm_shuffle_epi32(_mm_castps_si128(xx1), _MM_SHUFFLE(2, 3, 2, 3))); | 
 |     a[j0 + 48] = -a[j0 + 48]; | 
 |  | 
 |     _mm_storel_epi64((__m128i*)&a[j0 + 8], _mm_castps_si128(x1_x3_add)); | 
 |     _mm_storel_epi64((__m128i*)&a[j0 + 24], _mm_castps_si128(x1_x3_sub)); | 
 |  | 
 |     _mm_storel_epi64((__m128i*)&a[j0 + 40], _mm_castps_si128(yy4)); | 
 |     _mm_storel_epi64( | 
 |         (__m128i*)&a[j0 + 56], | 
 |         _mm_shuffle_epi32(_mm_castps_si128(yy4), _MM_SHUFFLE(2, 3, 2, 3))); | 
 |   } | 
 |  | 
 |   { | 
 |     int k = 64; | 
 |     int k1 = 2; | 
 |     int k2 = 2 * k1; | 
 |     const __m128 wk2rv = _mm_load_ps(&rdft_wk2r[k2 + 0]); | 
 |     const __m128 wk2iv = _mm_load_ps(&rdft_wk2i[k2 + 0]); | 
 |     const __m128 wk1iv = _mm_load_ps(&rdft_wk1i[k2 + 0]); | 
 |     const __m128 wk3rv = _mm_load_ps(&rdft_wk3r[k2 + 0]); | 
 |     const __m128 wk3iv = _mm_load_ps(&rdft_wk3i[k2 + 0]); | 
 |     wk1rv = _mm_load_ps(&rdft_wk1r[k2 + 0]); | 
 |     for (j0 = k; j0 < l + k; j0 += 2) { | 
 |       const __m128i a_00 = _mm_loadl_epi64((__m128i*)&a[j0 + 0]); | 
 |       const __m128i a_08 = _mm_loadl_epi64((__m128i*)&a[j0 + 8]); | 
 |       const __m128i a_32 = _mm_loadl_epi64((__m128i*)&a[j0 + 32]); | 
 |       const __m128i a_40 = _mm_loadl_epi64((__m128i*)&a[j0 + 40]); | 
 |       const __m128 a_00_32 = | 
 |           _mm_shuffle_ps(_mm_castsi128_ps(a_00), _mm_castsi128_ps(a_32), | 
 |                          _MM_SHUFFLE(1, 0, 1, 0)); | 
 |       const __m128 a_08_40 = | 
 |           _mm_shuffle_ps(_mm_castsi128_ps(a_08), _mm_castsi128_ps(a_40), | 
 |                          _MM_SHUFFLE(1, 0, 1, 0)); | 
 |       __m128 x0r0_0i0_0r1_x0i1 = _mm_add_ps(a_00_32, a_08_40); | 
 |       const __m128 x1r0_1i0_1r1_x1i1 = _mm_sub_ps(a_00_32, a_08_40); | 
 |  | 
 |       const __m128i a_16 = _mm_loadl_epi64((__m128i*)&a[j0 + 16]); | 
 |       const __m128i a_24 = _mm_loadl_epi64((__m128i*)&a[j0 + 24]); | 
 |       const __m128i a_48 = _mm_loadl_epi64((__m128i*)&a[j0 + 48]); | 
 |       const __m128i a_56 = _mm_loadl_epi64((__m128i*)&a[j0 + 56]); | 
 |       const __m128 a_16_48 = | 
 |           _mm_shuffle_ps(_mm_castsi128_ps(a_16), _mm_castsi128_ps(a_48), | 
 |                          _MM_SHUFFLE(1, 0, 1, 0)); | 
 |       const __m128 a_24_56 = | 
 |           _mm_shuffle_ps(_mm_castsi128_ps(a_24), _mm_castsi128_ps(a_56), | 
 |                          _MM_SHUFFLE(1, 0, 1, 0)); | 
 |       const __m128 x2r0_2i0_2r1_x2i1 = _mm_add_ps(a_16_48, a_24_56); | 
 |       const __m128 x3r0_3i0_3r1_x3i1 = _mm_sub_ps(a_16_48, a_24_56); | 
 |  | 
 |       const __m128 xx = _mm_add_ps(x0r0_0i0_0r1_x0i1, x2r0_2i0_2r1_x2i1); | 
 |       const __m128 xx1 = _mm_sub_ps(x0r0_0i0_0r1_x0i1, x2r0_2i0_2r1_x2i1); | 
 |       const __m128 xx2 = _mm_mul_ps(xx1, wk2rv); | 
 |       const __m128 xx3 = _mm_mul_ps( | 
 |           wk2iv, _mm_castsi128_ps(_mm_shuffle_epi32(_mm_castps_si128(xx1), | 
 |                                                     _MM_SHUFFLE(2, 3, 0, 1)))); | 
 |       const __m128 xx4 = _mm_add_ps(xx2, xx3); | 
 |  | 
 |       const __m128 x3i0_3r0_3i1_x3r1 = _mm_castsi128_ps(_mm_shuffle_epi32( | 
 |           _mm_castps_si128(x3r0_3i0_3r1_x3i1), _MM_SHUFFLE(2, 3, 0, 1))); | 
 |       const __m128 x3_swapped = _mm_mul_ps(mm_swap_sign, x3i0_3r0_3i1_x3r1); | 
 |       const __m128 x1_x3_add = _mm_add_ps(x1r0_1i0_1r1_x1i1, x3_swapped); | 
 |       const __m128 x1_x3_sub = _mm_sub_ps(x1r0_1i0_1r1_x1i1, x3_swapped); | 
 |  | 
 |       const __m128 xx10 = _mm_mul_ps(x1_x3_add, wk1rv); | 
 |       const __m128 xx11 = _mm_mul_ps( | 
 |           wk1iv, _mm_castsi128_ps(_mm_shuffle_epi32(_mm_castps_si128(x1_x3_add), | 
 |                                                     _MM_SHUFFLE(2, 3, 0, 1)))); | 
 |       const __m128 xx12 = _mm_add_ps(xx10, xx11); | 
 |  | 
 |       const __m128 xx20 = _mm_mul_ps(x1_x3_sub, wk3rv); | 
 |       const __m128 xx21 = _mm_mul_ps( | 
 |           wk3iv, _mm_castsi128_ps(_mm_shuffle_epi32(_mm_castps_si128(x1_x3_sub), | 
 |                                                     _MM_SHUFFLE(2, 3, 0, 1)))); | 
 |       const __m128 xx22 = _mm_add_ps(xx20, xx21); | 
 |  | 
 |       _mm_storel_epi64((__m128i*)&a[j0 + 0], _mm_castps_si128(xx)); | 
 |       _mm_storel_epi64( | 
 |           (__m128i*)&a[j0 + 32], | 
 |           _mm_shuffle_epi32(_mm_castps_si128(xx), _MM_SHUFFLE(3, 2, 3, 2))); | 
 |  | 
 |       _mm_storel_epi64((__m128i*)&a[j0 + 16], _mm_castps_si128(xx4)); | 
 |       _mm_storel_epi64( | 
 |           (__m128i*)&a[j0 + 48], | 
 |           _mm_shuffle_epi32(_mm_castps_si128(xx4), _MM_SHUFFLE(3, 2, 3, 2))); | 
 |  | 
 |       _mm_storel_epi64((__m128i*)&a[j0 + 8], _mm_castps_si128(xx12)); | 
 |       _mm_storel_epi64( | 
 |           (__m128i*)&a[j0 + 40], | 
 |           _mm_shuffle_epi32(_mm_castps_si128(xx12), _MM_SHUFFLE(3, 2, 3, 2))); | 
 |  | 
 |       _mm_storel_epi64((__m128i*)&a[j0 + 24], _mm_castps_si128(xx22)); | 
 |       _mm_storel_epi64( | 
 |           (__m128i*)&a[j0 + 56], | 
 |           _mm_shuffle_epi32(_mm_castps_si128(xx22), _MM_SHUFFLE(3, 2, 3, 2))); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void rftfsub_128_SSE2(float* a) { | 
 |   const float* c = rdft_w + 32; | 
 |   int j1, j2, k1, k2; | 
 |   float wkr, wki, xr, xi, yr, yi; | 
 |  | 
 |   static const ALIGN16_BEG float ALIGN16_END k_half[4] = {0.5f, 0.5f, 0.5f, | 
 |                                                           0.5f}; | 
 |   const __m128 mm_half = _mm_load_ps(k_half); | 
 |  | 
 |   // Vectorized code (four at once). | 
 |   //    Note: commented number are indexes for the first iteration of the loop. | 
 |   for (j1 = 1, j2 = 2; j2 + 7 < 64; j1 += 4, j2 += 8) { | 
 |     // Load 'wk'. | 
 |     const __m128 c_j1 = _mm_loadu_ps(&c[j1]);       //  1,  2,  3,  4, | 
 |     const __m128 c_k1 = _mm_loadu_ps(&c[29 - j1]);  // 28, 29, 30, 31, | 
 |     const __m128 wkrt = _mm_sub_ps(mm_half, c_k1);  // 28, 29, 30, 31, | 
 |     const __m128 wkr_ = | 
 |         _mm_shuffle_ps(wkrt, wkrt, _MM_SHUFFLE(0, 1, 2, 3));  // 31, 30, 29, 28, | 
 |     const __m128 wki_ = c_j1;                                 //  1,  2,  3,  4, | 
 |     // Load and shuffle 'a'. | 
 |     const __m128 a_j2_0 = _mm_loadu_ps(&a[0 + j2]);    //   2,   3,   4,   5, | 
 |     const __m128 a_j2_4 = _mm_loadu_ps(&a[4 + j2]);    //   6,   7,   8,   9, | 
 |     const __m128 a_k2_0 = _mm_loadu_ps(&a[122 - j2]);  // 120, 121, 122, 123, | 
 |     const __m128 a_k2_4 = _mm_loadu_ps(&a[126 - j2]);  // 124, 125, 126, 127, | 
 |     const __m128 a_j2_p0 = _mm_shuffle_ps( | 
 |         a_j2_0, a_j2_4, _MM_SHUFFLE(2, 0, 2, 0));  //   2,   4,   6,   8, | 
 |     const __m128 a_j2_p1 = _mm_shuffle_ps( | 
 |         a_j2_0, a_j2_4, _MM_SHUFFLE(3, 1, 3, 1));  //   3,   5,   7,   9, | 
 |     const __m128 a_k2_p0 = _mm_shuffle_ps( | 
 |         a_k2_4, a_k2_0, _MM_SHUFFLE(0, 2, 0, 2));  // 126, 124, 122, 120, | 
 |     const __m128 a_k2_p1 = _mm_shuffle_ps( | 
 |         a_k2_4, a_k2_0, _MM_SHUFFLE(1, 3, 1, 3));  // 127, 125, 123, 121, | 
 |     // Calculate 'x'. | 
 |     const __m128 xr_ = _mm_sub_ps(a_j2_p0, a_k2_p0); | 
 |     // 2-126, 4-124, 6-122, 8-120, | 
 |     const __m128 xi_ = _mm_add_ps(a_j2_p1, a_k2_p1); | 
 |     // 3-127, 5-125, 7-123, 9-121, | 
 |     // Calculate product into 'y'. | 
 |     //    yr = wkr * xr - wki * xi; | 
 |     //    yi = wkr * xi + wki * xr; | 
 |     const __m128 a_ = _mm_mul_ps(wkr_, xr_); | 
 |     const __m128 b_ = _mm_mul_ps(wki_, xi_); | 
 |     const __m128 c_ = _mm_mul_ps(wkr_, xi_); | 
 |     const __m128 d_ = _mm_mul_ps(wki_, xr_); | 
 |     const __m128 yr_ = _mm_sub_ps(a_, b_);  // 2-126, 4-124, 6-122, 8-120, | 
 |     const __m128 yi_ = _mm_add_ps(c_, d_);  // 3-127, 5-125, 7-123, 9-121, | 
 |                                             // Update 'a'. | 
 |                                             //    a[j2 + 0] -= yr; | 
 |                                             //    a[j2 + 1] -= yi; | 
 |                                             //    a[k2 + 0] += yr; | 
 |     //    a[k2 + 1] -= yi; | 
 |     const __m128 a_j2_p0n = _mm_sub_ps(a_j2_p0, yr_);  //   2,   4,   6,   8, | 
 |     const __m128 a_j2_p1n = _mm_sub_ps(a_j2_p1, yi_);  //   3,   5,   7,   9, | 
 |     const __m128 a_k2_p0n = _mm_add_ps(a_k2_p0, yr_);  // 126, 124, 122, 120, | 
 |     const __m128 a_k2_p1n = _mm_sub_ps(a_k2_p1, yi_);  // 127, 125, 123, 121, | 
 |     // Shuffle in right order and store. | 
 |     const __m128 a_j2_0n = _mm_unpacklo_ps(a_j2_p0n, a_j2_p1n); | 
 |     //   2,   3,   4,   5, | 
 |     const __m128 a_j2_4n = _mm_unpackhi_ps(a_j2_p0n, a_j2_p1n); | 
 |     //   6,   7,   8,   9, | 
 |     const __m128 a_k2_0nt = _mm_unpackhi_ps(a_k2_p0n, a_k2_p1n); | 
 |     // 122, 123, 120, 121, | 
 |     const __m128 a_k2_4nt = _mm_unpacklo_ps(a_k2_p0n, a_k2_p1n); | 
 |     // 126, 127, 124, 125, | 
 |     const __m128 a_k2_0n = _mm_shuffle_ps( | 
 |         a_k2_0nt, a_k2_0nt, _MM_SHUFFLE(1, 0, 3, 2));  // 120, 121, 122, 123, | 
 |     const __m128 a_k2_4n = _mm_shuffle_ps( | 
 |         a_k2_4nt, a_k2_4nt, _MM_SHUFFLE(1, 0, 3, 2));  // 124, 125, 126, 127, | 
 |     _mm_storeu_ps(&a[0 + j2], a_j2_0n); | 
 |     _mm_storeu_ps(&a[4 + j2], a_j2_4n); | 
 |     _mm_storeu_ps(&a[122 - j2], a_k2_0n); | 
 |     _mm_storeu_ps(&a[126 - j2], a_k2_4n); | 
 |   } | 
 |   // Scalar code for the remaining items. | 
 |   for (; j2 < 64; j1 += 1, j2 += 2) { | 
 |     k2 = 128 - j2; | 
 |     k1 = 32 - j1; | 
 |     wkr = 0.5f - c[k1]; | 
 |     wki = c[j1]; | 
 |     xr = a[j2 + 0] - a[k2 + 0]; | 
 |     xi = a[j2 + 1] + a[k2 + 1]; | 
 |     yr = wkr * xr - wki * xi; | 
 |     yi = wkr * xi + wki * xr; | 
 |     a[j2 + 0] -= yr; | 
 |     a[j2 + 1] -= yi; | 
 |     a[k2 + 0] += yr; | 
 |     a[k2 + 1] -= yi; | 
 |   } | 
 | } | 
 |  | 
 | void rftbsub_128_SSE2(float* a) { | 
 |   const float* c = rdft_w + 32; | 
 |   int j1, j2, k1, k2; | 
 |   float wkr, wki, xr, xi, yr, yi; | 
 |  | 
 |   static const ALIGN16_BEG float ALIGN16_END k_half[4] = {0.5f, 0.5f, 0.5f, | 
 |                                                           0.5f}; | 
 |   const __m128 mm_half = _mm_load_ps(k_half); | 
 |  | 
 |   a[1] = -a[1]; | 
 |   // Vectorized code (four at once). | 
 |   //    Note: commented number are indexes for the first iteration of the loop. | 
 |   for (j1 = 1, j2 = 2; j2 + 7 < 64; j1 += 4, j2 += 8) { | 
 |     // Load 'wk'. | 
 |     const __m128 c_j1 = _mm_loadu_ps(&c[j1]);       //  1,  2,  3,  4, | 
 |     const __m128 c_k1 = _mm_loadu_ps(&c[29 - j1]);  // 28, 29, 30, 31, | 
 |     const __m128 wkrt = _mm_sub_ps(mm_half, c_k1);  // 28, 29, 30, 31, | 
 |     const __m128 wkr_ = | 
 |         _mm_shuffle_ps(wkrt, wkrt, _MM_SHUFFLE(0, 1, 2, 3));  // 31, 30, 29, 28, | 
 |     const __m128 wki_ = c_j1;                                 //  1,  2,  3,  4, | 
 |     // Load and shuffle 'a'. | 
 |     const __m128 a_j2_0 = _mm_loadu_ps(&a[0 + j2]);    //   2,   3,   4,   5, | 
 |     const __m128 a_j2_4 = _mm_loadu_ps(&a[4 + j2]);    //   6,   7,   8,   9, | 
 |     const __m128 a_k2_0 = _mm_loadu_ps(&a[122 - j2]);  // 120, 121, 122, 123, | 
 |     const __m128 a_k2_4 = _mm_loadu_ps(&a[126 - j2]);  // 124, 125, 126, 127, | 
 |     const __m128 a_j2_p0 = _mm_shuffle_ps( | 
 |         a_j2_0, a_j2_4, _MM_SHUFFLE(2, 0, 2, 0));  //   2,   4,   6,   8, | 
 |     const __m128 a_j2_p1 = _mm_shuffle_ps( | 
 |         a_j2_0, a_j2_4, _MM_SHUFFLE(3, 1, 3, 1));  //   3,   5,   7,   9, | 
 |     const __m128 a_k2_p0 = _mm_shuffle_ps( | 
 |         a_k2_4, a_k2_0, _MM_SHUFFLE(0, 2, 0, 2));  // 126, 124, 122, 120, | 
 |     const __m128 a_k2_p1 = _mm_shuffle_ps( | 
 |         a_k2_4, a_k2_0, _MM_SHUFFLE(1, 3, 1, 3));  // 127, 125, 123, 121, | 
 |     // Calculate 'x'. | 
 |     const __m128 xr_ = _mm_sub_ps(a_j2_p0, a_k2_p0); | 
 |     // 2-126, 4-124, 6-122, 8-120, | 
 |     const __m128 xi_ = _mm_add_ps(a_j2_p1, a_k2_p1); | 
 |     // 3-127, 5-125, 7-123, 9-121, | 
 |     // Calculate product into 'y'. | 
 |     //    yr = wkr * xr + wki * xi; | 
 |     //    yi = wkr * xi - wki * xr; | 
 |     const __m128 a_ = _mm_mul_ps(wkr_, xr_); | 
 |     const __m128 b_ = _mm_mul_ps(wki_, xi_); | 
 |     const __m128 c_ = _mm_mul_ps(wkr_, xi_); | 
 |     const __m128 d_ = _mm_mul_ps(wki_, xr_); | 
 |     const __m128 yr_ = _mm_add_ps(a_, b_);  // 2-126, 4-124, 6-122, 8-120, | 
 |     const __m128 yi_ = _mm_sub_ps(c_, d_);  // 3-127, 5-125, 7-123, 9-121, | 
 |                                             // Update 'a'. | 
 |                                             //    a[j2 + 0] = a[j2 + 0] - yr; | 
 |                                             //    a[j2 + 1] = yi - a[j2 + 1]; | 
 |                                             //    a[k2 + 0] = yr + a[k2 + 0]; | 
 |     //    a[k2 + 1] = yi - a[k2 + 1]; | 
 |     const __m128 a_j2_p0n = _mm_sub_ps(a_j2_p0, yr_);  //   2,   4,   6,   8, | 
 |     const __m128 a_j2_p1n = _mm_sub_ps(yi_, a_j2_p1);  //   3,   5,   7,   9, | 
 |     const __m128 a_k2_p0n = _mm_add_ps(a_k2_p0, yr_);  // 126, 124, 122, 120, | 
 |     const __m128 a_k2_p1n = _mm_sub_ps(yi_, a_k2_p1);  // 127, 125, 123, 121, | 
 |     // Shuffle in right order and store. | 
 |     const __m128 a_j2_0n = _mm_unpacklo_ps(a_j2_p0n, a_j2_p1n); | 
 |     //   2,   3,   4,   5, | 
 |     const __m128 a_j2_4n = _mm_unpackhi_ps(a_j2_p0n, a_j2_p1n); | 
 |     //   6,   7,   8,   9, | 
 |     const __m128 a_k2_0nt = _mm_unpackhi_ps(a_k2_p0n, a_k2_p1n); | 
 |     // 122, 123, 120, 121, | 
 |     const __m128 a_k2_4nt = _mm_unpacklo_ps(a_k2_p0n, a_k2_p1n); | 
 |     // 126, 127, 124, 125, | 
 |     const __m128 a_k2_0n = _mm_shuffle_ps( | 
 |         a_k2_0nt, a_k2_0nt, _MM_SHUFFLE(1, 0, 3, 2));  // 120, 121, 122, 123, | 
 |     const __m128 a_k2_4n = _mm_shuffle_ps( | 
 |         a_k2_4nt, a_k2_4nt, _MM_SHUFFLE(1, 0, 3, 2));  // 124, 125, 126, 127, | 
 |     _mm_storeu_ps(&a[0 + j2], a_j2_0n); | 
 |     _mm_storeu_ps(&a[4 + j2], a_j2_4n); | 
 |     _mm_storeu_ps(&a[122 - j2], a_k2_0n); | 
 |     _mm_storeu_ps(&a[126 - j2], a_k2_4n); | 
 |   } | 
 |   // Scalar code for the remaining items. | 
 |   for (; j2 < 64; j1 += 1, j2 += 2) { | 
 |     k2 = 128 - j2; | 
 |     k1 = 32 - j1; | 
 |     wkr = 0.5f - c[k1]; | 
 |     wki = c[j1]; | 
 |     xr = a[j2 + 0] - a[k2 + 0]; | 
 |     xi = a[j2 + 1] + a[k2 + 1]; | 
 |     yr = wkr * xr + wki * xi; | 
 |     yi = wkr * xi - wki * xr; | 
 |     a[j2 + 0] = a[j2 + 0] - yr; | 
 |     a[j2 + 1] = yi - a[j2 + 1]; | 
 |     a[k2 + 0] = yr + a[k2 + 0]; | 
 |     a[k2 + 1] = yi - a[k2 + 1]; | 
 |   } | 
 |   a[65] = -a[65]; | 
 | } | 
 | #endif | 
 |  | 
 | }  // namespace webrtc |