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      1 /*
      2  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 /*
     12  * The core AEC algorithm, neon version of speed-critical functions.
     13  *
     14  * Based on aec_core_sse2.c.
     15  */
     16 
     17 #include <arm_neon.h>
     18 #include <math.h>
     19 #include <string.h>  // memset
     20 
     21 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
     22 #include "webrtc/modules/audio_processing/aec/aec_common.h"
     23 #include "webrtc/modules/audio_processing/aec/aec_core_internal.h"
     24 #include "webrtc/modules/audio_processing/aec/aec_rdft.h"
     25 
     26 enum { kShiftExponentIntoTopMantissa = 8 };
     27 enum { kFloatExponentShift = 23 };
     28 
     29 __inline static float MulRe(float aRe, float aIm, float bRe, float bIm) {
     30   return aRe * bRe - aIm * bIm;
     31 }
     32 
     33 __inline static float MulIm(float aRe, float aIm, float bRe, float bIm) {
     34   return aRe * bIm + aIm * bRe;
     35 }
     36 
     37 static void FilterFarNEON(
     38     int num_partitions,
     39     int x_fft_buf_block_pos,
     40     float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
     41     float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
     42     float y_fft[2][PART_LEN1]) {
     43   int i;
     44   for (i = 0; i < num_partitions; i++) {
     45     int j;
     46     int xPos = (i + x_fft_buf_block_pos) * PART_LEN1;
     47     int pos = i * PART_LEN1;
     48     // Check for wrap
     49     if (i + x_fft_buf_block_pos >= num_partitions) {
     50       xPos -= num_partitions * PART_LEN1;
     51     }
     52 
     53     // vectorized code (four at once)
     54     for (j = 0; j + 3 < PART_LEN1; j += 4) {
     55       const float32x4_t x_fft_buf_re = vld1q_f32(&x_fft_buf[0][xPos + j]);
     56       const float32x4_t x_fft_buf_im = vld1q_f32(&x_fft_buf[1][xPos + j]);
     57       const float32x4_t h_fft_buf_re = vld1q_f32(&h_fft_buf[0][pos + j]);
     58       const float32x4_t h_fft_buf_im = vld1q_f32(&h_fft_buf[1][pos + j]);
     59       const float32x4_t y_fft_re = vld1q_f32(&y_fft[0][j]);
     60       const float32x4_t y_fft_im = vld1q_f32(&y_fft[1][j]);
     61       const float32x4_t a = vmulq_f32(x_fft_buf_re, h_fft_buf_re);
     62       const float32x4_t e = vmlsq_f32(a, x_fft_buf_im, h_fft_buf_im);
     63       const float32x4_t c = vmulq_f32(x_fft_buf_re, h_fft_buf_im);
     64       const float32x4_t f = vmlaq_f32(c, x_fft_buf_im, h_fft_buf_re);
     65       const float32x4_t g = vaddq_f32(y_fft_re, e);
     66       const float32x4_t h = vaddq_f32(y_fft_im, f);
     67       vst1q_f32(&y_fft[0][j], g);
     68       vst1q_f32(&y_fft[1][j], h);
     69     }
     70     // scalar code for the remaining items.
     71     for (; j < PART_LEN1; j++) {
     72       y_fft[0][j] += MulRe(x_fft_buf[0][xPos + j],
     73                            x_fft_buf[1][xPos + j],
     74                            h_fft_buf[0][pos + j],
     75                            h_fft_buf[1][pos + j]);
     76       y_fft[1][j] += MulIm(x_fft_buf[0][xPos + j],
     77                            x_fft_buf[1][xPos + j],
     78                            h_fft_buf[0][pos + j],
     79                            h_fft_buf[1][pos + j]);
     80     }
     81   }
     82 }
     83 
     84 // ARM64's arm_neon.h has already defined vdivq_f32 vsqrtq_f32.
     85 #if !defined (WEBRTC_ARCH_ARM64)
     86 static float32x4_t vdivq_f32(float32x4_t a, float32x4_t b) {
     87   int i;
     88   float32x4_t x = vrecpeq_f32(b);
     89   // from arm documentation
     90   // The Newton-Raphson iteration:
     91   //     x[n+1] = x[n] * (2 - d * x[n])
     92   // converges to (1/d) if x0 is the result of VRECPE applied to d.
     93   //
     94   // Note: The precision did not improve after 2 iterations.
     95   for (i = 0; i < 2; i++) {
     96     x = vmulq_f32(vrecpsq_f32(b, x), x);
     97   }
     98   // a/b = a*(1/b)
     99   return vmulq_f32(a, x);
    100 }
    101 
    102 static float32x4_t vsqrtq_f32(float32x4_t s) {
    103   int i;
    104   float32x4_t x = vrsqrteq_f32(s);
    105 
    106   // Code to handle sqrt(0).
    107   // If the input to sqrtf() is zero, a zero will be returned.
    108   // If the input to vrsqrteq_f32() is zero, positive infinity is returned.
    109   const uint32x4_t vec_p_inf = vdupq_n_u32(0x7F800000);
    110   // check for divide by zero
    111   const uint32x4_t div_by_zero = vceqq_u32(vec_p_inf, vreinterpretq_u32_f32(x));
    112   // zero out the positive infinity results
    113   x = vreinterpretq_f32_u32(vandq_u32(vmvnq_u32(div_by_zero),
    114                                       vreinterpretq_u32_f32(x)));
    115   // from arm documentation
    116   // The Newton-Raphson iteration:
    117   //     x[n+1] = x[n] * (3 - d * (x[n] * x[n])) / 2)
    118   // converges to (1/d) if x0 is the result of VRSQRTE applied to d.
    119   //
    120   // Note: The precision did not improve after 2 iterations.
    121   for (i = 0; i < 2; i++) {
    122     x = vmulq_f32(vrsqrtsq_f32(vmulq_f32(x, x), s), x);
    123   }
    124   // sqrt(s) = s * 1/sqrt(s)
    125   return vmulq_f32(s, x);;
    126 }
    127 #endif  // WEBRTC_ARCH_ARM64
    128 
    129 static void ScaleErrorSignalNEON(int extended_filter_enabled,
    130                                  float normal_mu,
    131                                  float normal_error_threshold,
    132                                  float x_pow[PART_LEN1],
    133                                  float ef[2][PART_LEN1]) {
    134   const float mu = extended_filter_enabled ? kExtendedMu : normal_mu;
    135   const float error_threshold = extended_filter_enabled ?
    136       kExtendedErrorThreshold : normal_error_threshold;
    137   const float32x4_t k1e_10f = vdupq_n_f32(1e-10f);
    138   const float32x4_t kMu = vmovq_n_f32(mu);
    139   const float32x4_t kThresh = vmovq_n_f32(error_threshold);
    140   int i;
    141   // vectorized code (four at once)
    142   for (i = 0; i + 3 < PART_LEN1; i += 4) {
    143     const float32x4_t x_pow_local = vld1q_f32(&x_pow[i]);
    144     const float32x4_t ef_re_base = vld1q_f32(&ef[0][i]);
    145     const float32x4_t ef_im_base = vld1q_f32(&ef[1][i]);
    146     const float32x4_t xPowPlus = vaddq_f32(x_pow_local, k1e_10f);
    147     float32x4_t ef_re = vdivq_f32(ef_re_base, xPowPlus);
    148     float32x4_t ef_im = vdivq_f32(ef_im_base, xPowPlus);
    149     const float32x4_t ef_re2 = vmulq_f32(ef_re, ef_re);
    150     const float32x4_t ef_sum2 = vmlaq_f32(ef_re2, ef_im, ef_im);
    151     const float32x4_t absEf = vsqrtq_f32(ef_sum2);
    152     const uint32x4_t bigger = vcgtq_f32(absEf, kThresh);
    153     const float32x4_t absEfPlus = vaddq_f32(absEf, k1e_10f);
    154     const float32x4_t absEfInv = vdivq_f32(kThresh, absEfPlus);
    155     uint32x4_t ef_re_if = vreinterpretq_u32_f32(vmulq_f32(ef_re, absEfInv));
    156     uint32x4_t ef_im_if = vreinterpretq_u32_f32(vmulq_f32(ef_im, absEfInv));
    157     uint32x4_t ef_re_u32 = vandq_u32(vmvnq_u32(bigger),
    158                                      vreinterpretq_u32_f32(ef_re));
    159     uint32x4_t ef_im_u32 = vandq_u32(vmvnq_u32(bigger),
    160                                      vreinterpretq_u32_f32(ef_im));
    161     ef_re_if = vandq_u32(bigger, ef_re_if);
    162     ef_im_if = vandq_u32(bigger, ef_im_if);
    163     ef_re_u32 = vorrq_u32(ef_re_u32, ef_re_if);
    164     ef_im_u32 = vorrq_u32(ef_im_u32, ef_im_if);
    165     ef_re = vmulq_f32(vreinterpretq_f32_u32(ef_re_u32), kMu);
    166     ef_im = vmulq_f32(vreinterpretq_f32_u32(ef_im_u32), kMu);
    167     vst1q_f32(&ef[0][i], ef_re);
    168     vst1q_f32(&ef[1][i], ef_im);
    169   }
    170   // scalar code for the remaining items.
    171   for (; i < PART_LEN1; i++) {
    172     float abs_ef;
    173     ef[0][i] /= (x_pow[i] + 1e-10f);
    174     ef[1][i] /= (x_pow[i] + 1e-10f);
    175     abs_ef = sqrtf(ef[0][i] * ef[0][i] + ef[1][i] * ef[1][i]);
    176 
    177     if (abs_ef > error_threshold) {
    178       abs_ef = error_threshold / (abs_ef + 1e-10f);
    179       ef[0][i] *= abs_ef;
    180       ef[1][i] *= abs_ef;
    181     }
    182 
    183     // Stepsize factor
    184     ef[0][i] *= mu;
    185     ef[1][i] *= mu;
    186   }
    187 }
    188 
    189 static void FilterAdaptationNEON(
    190     int num_partitions,
    191     int x_fft_buf_block_pos,
    192     float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
    193     float e_fft[2][PART_LEN1],
    194     float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1]) {
    195   float fft[PART_LEN2];
    196   int i;
    197   for (i = 0; i < num_partitions; i++) {
    198     int xPos = (i + x_fft_buf_block_pos) * PART_LEN1;
    199     int pos = i * PART_LEN1;
    200     int j;
    201     // Check for wrap
    202     if (i + x_fft_buf_block_pos >= num_partitions) {
    203       xPos -= num_partitions * PART_LEN1;
    204     }
    205 
    206     // Process the whole array...
    207     for (j = 0; j < PART_LEN; j += 4) {
    208       // Load x_fft_buf and e_fft.
    209       const float32x4_t x_fft_buf_re = vld1q_f32(&x_fft_buf[0][xPos + j]);
    210       const float32x4_t x_fft_buf_im = vld1q_f32(&x_fft_buf[1][xPos + j]);
    211       const float32x4_t e_fft_re = vld1q_f32(&e_fft[0][j]);
    212       const float32x4_t e_fft_im = vld1q_f32(&e_fft[1][j]);
    213       // Calculate the product of conjugate(x_fft_buf) by e_fft.
    214       //   re(conjugate(a) * b) = aRe * bRe + aIm * bIm
    215       //   im(conjugate(a) * b)=  aRe * bIm - aIm * bRe
    216       const float32x4_t a = vmulq_f32(x_fft_buf_re, e_fft_re);
    217       const float32x4_t e = vmlaq_f32(a, x_fft_buf_im, e_fft_im);
    218       const float32x4_t c = vmulq_f32(x_fft_buf_re, e_fft_im);
    219       const float32x4_t f = vmlsq_f32(c, x_fft_buf_im, e_fft_re);
    220       // Interleave real and imaginary parts.
    221       const float32x4x2_t g_n_h = vzipq_f32(e, f);
    222       // Store
    223       vst1q_f32(&fft[2 * j + 0], g_n_h.val[0]);
    224       vst1q_f32(&fft[2 * j + 4], g_n_h.val[1]);
    225     }
    226     // ... and fixup the first imaginary entry.
    227     fft[1] = MulRe(x_fft_buf[0][xPos + PART_LEN],
    228                    -x_fft_buf[1][xPos + PART_LEN],
    229                    e_fft[0][PART_LEN],
    230                    e_fft[1][PART_LEN]);
    231 
    232     aec_rdft_inverse_128(fft);
    233     memset(fft + PART_LEN, 0, sizeof(float) * PART_LEN);
    234 
    235     // fft scaling
    236     {
    237       const float scale = 2.0f / PART_LEN2;
    238       const float32x4_t scale_ps = vmovq_n_f32(scale);
    239       for (j = 0; j < PART_LEN; j += 4) {
    240         const float32x4_t fft_ps = vld1q_f32(&fft[j]);
    241         const float32x4_t fft_scale = vmulq_f32(fft_ps, scale_ps);
    242         vst1q_f32(&fft[j], fft_scale);
    243       }
    244     }
    245     aec_rdft_forward_128(fft);
    246 
    247     {
    248       const float wt1 = h_fft_buf[1][pos];
    249       h_fft_buf[0][pos + PART_LEN] += fft[1];
    250       for (j = 0; j < PART_LEN; j += 4) {
    251         float32x4_t wtBuf_re = vld1q_f32(&h_fft_buf[0][pos + j]);
    252         float32x4_t wtBuf_im = vld1q_f32(&h_fft_buf[1][pos + j]);
    253         const float32x4_t fft0 = vld1q_f32(&fft[2 * j + 0]);
    254         const float32x4_t fft4 = vld1q_f32(&fft[2 * j + 4]);
    255         const float32x4x2_t fft_re_im = vuzpq_f32(fft0, fft4);
    256         wtBuf_re = vaddq_f32(wtBuf_re, fft_re_im.val[0]);
    257         wtBuf_im = vaddq_f32(wtBuf_im, fft_re_im.val[1]);
    258 
    259         vst1q_f32(&h_fft_buf[0][pos + j], wtBuf_re);
    260         vst1q_f32(&h_fft_buf[1][pos + j], wtBuf_im);
    261       }
    262       h_fft_buf[1][pos] = wt1;
    263     }
    264   }
    265 }
    266 
    267 static float32x4_t vpowq_f32(float32x4_t a, float32x4_t b) {
    268   // a^b = exp2(b * log2(a))
    269   //   exp2(x) and log2(x) are calculated using polynomial approximations.
    270   float32x4_t log2_a, b_log2_a, a_exp_b;
    271 
    272   // Calculate log2(x), x = a.
    273   {
    274     // To calculate log2(x), we decompose x like this:
    275     //   x = y * 2^n
    276     //     n is an integer
    277     //     y is in the [1.0, 2.0) range
    278     //
    279     //   log2(x) = log2(y) + n
    280     //     n       can be evaluated by playing with float representation.
    281     //     log2(y) in a small range can be approximated, this code uses an order
    282     //             five polynomial approximation. The coefficients have been
    283     //             estimated with the Remez algorithm and the resulting
    284     //             polynomial has a maximum relative error of 0.00086%.
    285 
    286     // Compute n.
    287     //    This is done by masking the exponent, shifting it into the top bit of
    288     //    the mantissa, putting eight into the biased exponent (to shift/
    289     //    compensate the fact that the exponent has been shifted in the top/
    290     //    fractional part and finally getting rid of the implicit leading one
    291     //    from the mantissa by substracting it out.
    292     const uint32x4_t vec_float_exponent_mask = vdupq_n_u32(0x7F800000);
    293     const uint32x4_t vec_eight_biased_exponent = vdupq_n_u32(0x43800000);
    294     const uint32x4_t vec_implicit_leading_one = vdupq_n_u32(0x43BF8000);
    295     const uint32x4_t two_n = vandq_u32(vreinterpretq_u32_f32(a),
    296                                        vec_float_exponent_mask);
    297     const uint32x4_t n_1 = vshrq_n_u32(two_n, kShiftExponentIntoTopMantissa);
    298     const uint32x4_t n_0 = vorrq_u32(n_1, vec_eight_biased_exponent);
    299     const float32x4_t n =
    300         vsubq_f32(vreinterpretq_f32_u32(n_0),
    301                   vreinterpretq_f32_u32(vec_implicit_leading_one));
    302     // Compute y.
    303     const uint32x4_t vec_mantissa_mask = vdupq_n_u32(0x007FFFFF);
    304     const uint32x4_t vec_zero_biased_exponent_is_one = vdupq_n_u32(0x3F800000);
    305     const uint32x4_t mantissa = vandq_u32(vreinterpretq_u32_f32(a),
    306                                           vec_mantissa_mask);
    307     const float32x4_t y =
    308         vreinterpretq_f32_u32(vorrq_u32(mantissa,
    309                                         vec_zero_biased_exponent_is_one));
    310     // Approximate log2(y) ~= (y - 1) * pol5(y).
    311     //    pol5(y) = C5 * y^5 + C4 * y^4 + C3 * y^3 + C2 * y^2 + C1 * y + C0
    312     const float32x4_t C5 = vdupq_n_f32(-3.4436006e-2f);
    313     const float32x4_t C4 = vdupq_n_f32(3.1821337e-1f);
    314     const float32x4_t C3 = vdupq_n_f32(-1.2315303f);
    315     const float32x4_t C2 = vdupq_n_f32(2.5988452f);
    316     const float32x4_t C1 = vdupq_n_f32(-3.3241990f);
    317     const float32x4_t C0 = vdupq_n_f32(3.1157899f);
    318     float32x4_t pol5_y = C5;
    319     pol5_y = vmlaq_f32(C4, y, pol5_y);
    320     pol5_y = vmlaq_f32(C3, y, pol5_y);
    321     pol5_y = vmlaq_f32(C2, y, pol5_y);
    322     pol5_y = vmlaq_f32(C1, y, pol5_y);
    323     pol5_y = vmlaq_f32(C0, y, pol5_y);
    324     const float32x4_t y_minus_one =
    325         vsubq_f32(y, vreinterpretq_f32_u32(vec_zero_biased_exponent_is_one));
    326     const float32x4_t log2_y = vmulq_f32(y_minus_one, pol5_y);
    327 
    328     // Combine parts.
    329     log2_a = vaddq_f32(n, log2_y);
    330   }
    331 
    332   // b * log2(a)
    333   b_log2_a = vmulq_f32(b, log2_a);
    334 
    335   // Calculate exp2(x), x = b * log2(a).
    336   {
    337     // To calculate 2^x, we decompose x like this:
    338     //   x = n + y
    339     //     n is an integer, the value of x - 0.5 rounded down, therefore
    340     //     y is in the [0.5, 1.5) range
    341     //
    342     //   2^x = 2^n * 2^y
    343     //     2^n can be evaluated by playing with float representation.
    344     //     2^y in a small range can be approximated, this code uses an order two
    345     //         polynomial approximation. The coefficients have been estimated
    346     //         with the Remez algorithm and the resulting polynomial has a
    347     //         maximum relative error of 0.17%.
    348     // To avoid over/underflow, we reduce the range of input to ]-127, 129].
    349     const float32x4_t max_input = vdupq_n_f32(129.f);
    350     const float32x4_t min_input = vdupq_n_f32(-126.99999f);
    351     const float32x4_t x_min = vminq_f32(b_log2_a, max_input);
    352     const float32x4_t x_max = vmaxq_f32(x_min, min_input);
    353     // Compute n.
    354     const float32x4_t half = vdupq_n_f32(0.5f);
    355     const float32x4_t x_minus_half = vsubq_f32(x_max, half);
    356     const int32x4_t x_minus_half_floor = vcvtq_s32_f32(x_minus_half);
    357 
    358     // Compute 2^n.
    359     const int32x4_t float_exponent_bias = vdupq_n_s32(127);
    360     const int32x4_t two_n_exponent =
    361         vaddq_s32(x_minus_half_floor, float_exponent_bias);
    362     const float32x4_t two_n =
    363         vreinterpretq_f32_s32(vshlq_n_s32(two_n_exponent, kFloatExponentShift));
    364     // Compute y.
    365     const float32x4_t y = vsubq_f32(x_max, vcvtq_f32_s32(x_minus_half_floor));
    366 
    367     // Approximate 2^y ~= C2 * y^2 + C1 * y + C0.
    368     const float32x4_t C2 = vdupq_n_f32(3.3718944e-1f);
    369     const float32x4_t C1 = vdupq_n_f32(6.5763628e-1f);
    370     const float32x4_t C0 = vdupq_n_f32(1.0017247f);
    371     float32x4_t exp2_y = C2;
    372     exp2_y = vmlaq_f32(C1, y, exp2_y);
    373     exp2_y = vmlaq_f32(C0, y, exp2_y);
    374 
    375     // Combine parts.
    376     a_exp_b = vmulq_f32(exp2_y, two_n);
    377   }
    378 
    379   return a_exp_b;
    380 }
    381 
    382 static void OverdriveAndSuppressNEON(AecCore* aec,
    383                                      float hNl[PART_LEN1],
    384                                      const float hNlFb,
    385                                      float efw[2][PART_LEN1]) {
    386   int i;
    387   const float32x4_t vec_hNlFb = vmovq_n_f32(hNlFb);
    388   const float32x4_t vec_one = vdupq_n_f32(1.0f);
    389   const float32x4_t vec_minus_one = vdupq_n_f32(-1.0f);
    390   const float32x4_t vec_overDriveSm = vmovq_n_f32(aec->overDriveSm);
    391 
    392   // vectorized code (four at once)
    393   for (i = 0; i + 3 < PART_LEN1; i += 4) {
    394     // Weight subbands
    395     float32x4_t vec_hNl = vld1q_f32(&hNl[i]);
    396     const float32x4_t vec_weightCurve = vld1q_f32(&WebRtcAec_weightCurve[i]);
    397     const uint32x4_t bigger = vcgtq_f32(vec_hNl, vec_hNlFb);
    398     const float32x4_t vec_weightCurve_hNlFb = vmulq_f32(vec_weightCurve,
    399                                                         vec_hNlFb);
    400     const float32x4_t vec_one_weightCurve = vsubq_f32(vec_one, vec_weightCurve);
    401     const float32x4_t vec_one_weightCurve_hNl = vmulq_f32(vec_one_weightCurve,
    402                                                           vec_hNl);
    403     const uint32x4_t vec_if0 = vandq_u32(vmvnq_u32(bigger),
    404                                          vreinterpretq_u32_f32(vec_hNl));
    405     const float32x4_t vec_one_weightCurve_add =
    406         vaddq_f32(vec_weightCurve_hNlFb, vec_one_weightCurve_hNl);
    407     const uint32x4_t vec_if1 =
    408         vandq_u32(bigger, vreinterpretq_u32_f32(vec_one_weightCurve_add));
    409 
    410     vec_hNl = vreinterpretq_f32_u32(vorrq_u32(vec_if0, vec_if1));
    411 
    412     {
    413       const float32x4_t vec_overDriveCurve =
    414           vld1q_f32(&WebRtcAec_overDriveCurve[i]);
    415       const float32x4_t vec_overDriveSm_overDriveCurve =
    416           vmulq_f32(vec_overDriveSm, vec_overDriveCurve);
    417       vec_hNl = vpowq_f32(vec_hNl, vec_overDriveSm_overDriveCurve);
    418       vst1q_f32(&hNl[i], vec_hNl);
    419     }
    420 
    421     // Suppress error signal
    422     {
    423       float32x4_t vec_efw_re = vld1q_f32(&efw[0][i]);
    424       float32x4_t vec_efw_im = vld1q_f32(&efw[1][i]);
    425       vec_efw_re = vmulq_f32(vec_efw_re, vec_hNl);
    426       vec_efw_im = vmulq_f32(vec_efw_im, vec_hNl);
    427 
    428       // Ooura fft returns incorrect sign on imaginary component. It matters
    429       // here because we are making an additive change with comfort noise.
    430       vec_efw_im = vmulq_f32(vec_efw_im, vec_minus_one);
    431       vst1q_f32(&efw[0][i], vec_efw_re);
    432       vst1q_f32(&efw[1][i], vec_efw_im);
    433     }
    434   }
    435 
    436   // scalar code for the remaining items.
    437   for (; i < PART_LEN1; i++) {
    438     // Weight subbands
    439     if (hNl[i] > hNlFb) {
    440       hNl[i] = WebRtcAec_weightCurve[i] * hNlFb +
    441                (1 - WebRtcAec_weightCurve[i]) * hNl[i];
    442     }
    443 
    444     hNl[i] = powf(hNl[i], aec->overDriveSm * WebRtcAec_overDriveCurve[i]);
    445 
    446     // Suppress error signal
    447     efw[0][i] *= hNl[i];
    448     efw[1][i] *= hNl[i];
    449 
    450     // Ooura fft returns incorrect sign on imaginary component. It matters
    451     // here because we are making an additive change with comfort noise.
    452     efw[1][i] *= -1;
    453   }
    454 }
    455 
    456 static int PartitionDelayNEON(const AecCore* aec) {
    457   // Measures the energy in each filter partition and returns the partition with
    458   // highest energy.
    459   // TODO(bjornv): Spread computational cost by computing one partition per
    460   // block?
    461   float wfEnMax = 0;
    462   int i;
    463   int delay = 0;
    464 
    465   for (i = 0; i < aec->num_partitions; i++) {
    466     int j;
    467     int pos = i * PART_LEN1;
    468     float wfEn = 0;
    469     float32x4_t vec_wfEn = vdupq_n_f32(0.0f);
    470     // vectorized code (four at once)
    471     for (j = 0; j + 3 < PART_LEN1; j += 4) {
    472       const float32x4_t vec_wfBuf0 = vld1q_f32(&aec->wfBuf[0][pos + j]);
    473       const float32x4_t vec_wfBuf1 = vld1q_f32(&aec->wfBuf[1][pos + j]);
    474       vec_wfEn = vmlaq_f32(vec_wfEn, vec_wfBuf0, vec_wfBuf0);
    475       vec_wfEn = vmlaq_f32(vec_wfEn, vec_wfBuf1, vec_wfBuf1);
    476     }
    477     {
    478       float32x2_t vec_total;
    479       // A B C D
    480       vec_total = vpadd_f32(vget_low_f32(vec_wfEn), vget_high_f32(vec_wfEn));
    481       // A+B C+D
    482       vec_total = vpadd_f32(vec_total, vec_total);
    483       // A+B+C+D A+B+C+D
    484       wfEn = vget_lane_f32(vec_total, 0);
    485     }
    486 
    487     // scalar code for the remaining items.
    488     for (; j < PART_LEN1; j++) {
    489       wfEn += aec->wfBuf[0][pos + j] * aec->wfBuf[0][pos + j] +
    490               aec->wfBuf[1][pos + j] * aec->wfBuf[1][pos + j];
    491     }
    492 
    493     if (wfEn > wfEnMax) {
    494       wfEnMax = wfEn;
    495       delay = i;
    496     }
    497   }
    498   return delay;
    499 }
    500 
    501 // Updates the following smoothed  Power Spectral Densities (PSD):
    502 //  - sd  : near-end
    503 //  - se  : residual echo
    504 //  - sx  : far-end
    505 //  - sde : cross-PSD of near-end and residual echo
    506 //  - sxd : cross-PSD of near-end and far-end
    507 //
    508 // In addition to updating the PSDs, also the filter diverge state is determined
    509 // upon actions are taken.
    510 static void SmoothedPSD(AecCore* aec,
    511                         float efw[2][PART_LEN1],
    512                         float dfw[2][PART_LEN1],
    513                         float xfw[2][PART_LEN1],
    514                         int* extreme_filter_divergence) {
    515   // Power estimate smoothing coefficients.
    516   const float* ptrGCoh = aec->extended_filter_enabled
    517       ? WebRtcAec_kExtendedSmoothingCoefficients[aec->mult - 1]
    518       : WebRtcAec_kNormalSmoothingCoefficients[aec->mult - 1];
    519   int i;
    520   float sdSum = 0, seSum = 0;
    521   const float32x4_t vec_15 =  vdupq_n_f32(WebRtcAec_kMinFarendPSD);
    522   float32x4_t vec_sdSum = vdupq_n_f32(0.0f);
    523   float32x4_t vec_seSum = vdupq_n_f32(0.0f);
    524 
    525   for (i = 0; i + 3 < PART_LEN1; i += 4) {
    526     const float32x4_t vec_dfw0 = vld1q_f32(&dfw[0][i]);
    527     const float32x4_t vec_dfw1 = vld1q_f32(&dfw[1][i]);
    528     const float32x4_t vec_efw0 = vld1q_f32(&efw[0][i]);
    529     const float32x4_t vec_efw1 = vld1q_f32(&efw[1][i]);
    530     const float32x4_t vec_xfw0 = vld1q_f32(&xfw[0][i]);
    531     const float32x4_t vec_xfw1 = vld1q_f32(&xfw[1][i]);
    532     float32x4_t vec_sd = vmulq_n_f32(vld1q_f32(&aec->sd[i]), ptrGCoh[0]);
    533     float32x4_t vec_se = vmulq_n_f32(vld1q_f32(&aec->se[i]), ptrGCoh[0]);
    534     float32x4_t vec_sx = vmulq_n_f32(vld1q_f32(&aec->sx[i]), ptrGCoh[0]);
    535     float32x4_t vec_dfw_sumsq = vmulq_f32(vec_dfw0, vec_dfw0);
    536     float32x4_t vec_efw_sumsq = vmulq_f32(vec_efw0, vec_efw0);
    537     float32x4_t vec_xfw_sumsq = vmulq_f32(vec_xfw0, vec_xfw0);
    538 
    539     vec_dfw_sumsq = vmlaq_f32(vec_dfw_sumsq, vec_dfw1, vec_dfw1);
    540     vec_efw_sumsq = vmlaq_f32(vec_efw_sumsq, vec_efw1, vec_efw1);
    541     vec_xfw_sumsq = vmlaq_f32(vec_xfw_sumsq, vec_xfw1, vec_xfw1);
    542     vec_xfw_sumsq = vmaxq_f32(vec_xfw_sumsq, vec_15);
    543     vec_sd = vmlaq_n_f32(vec_sd, vec_dfw_sumsq, ptrGCoh[1]);
    544     vec_se = vmlaq_n_f32(vec_se, vec_efw_sumsq, ptrGCoh[1]);
    545     vec_sx = vmlaq_n_f32(vec_sx, vec_xfw_sumsq, ptrGCoh[1]);
    546 
    547     vst1q_f32(&aec->sd[i], vec_sd);
    548     vst1q_f32(&aec->se[i], vec_se);
    549     vst1q_f32(&aec->sx[i], vec_sx);
    550 
    551     {
    552       float32x4x2_t vec_sde = vld2q_f32(&aec->sde[i][0]);
    553       float32x4_t vec_dfwefw0011 = vmulq_f32(vec_dfw0, vec_efw0);
    554       float32x4_t vec_dfwefw0110 = vmulq_f32(vec_dfw0, vec_efw1);
    555       vec_sde.val[0] = vmulq_n_f32(vec_sde.val[0], ptrGCoh[0]);
    556       vec_sde.val[1] = vmulq_n_f32(vec_sde.val[1], ptrGCoh[0]);
    557       vec_dfwefw0011 = vmlaq_f32(vec_dfwefw0011, vec_dfw1, vec_efw1);
    558       vec_dfwefw0110 = vmlsq_f32(vec_dfwefw0110, vec_dfw1, vec_efw0);
    559       vec_sde.val[0] = vmlaq_n_f32(vec_sde.val[0], vec_dfwefw0011, ptrGCoh[1]);
    560       vec_sde.val[1] = vmlaq_n_f32(vec_sde.val[1], vec_dfwefw0110, ptrGCoh[1]);
    561       vst2q_f32(&aec->sde[i][0], vec_sde);
    562     }
    563 
    564     {
    565       float32x4x2_t vec_sxd = vld2q_f32(&aec->sxd[i][0]);
    566       float32x4_t vec_dfwxfw0011 = vmulq_f32(vec_dfw0, vec_xfw0);
    567       float32x4_t vec_dfwxfw0110 = vmulq_f32(vec_dfw0, vec_xfw1);
    568       vec_sxd.val[0] = vmulq_n_f32(vec_sxd.val[0], ptrGCoh[0]);
    569       vec_sxd.val[1] = vmulq_n_f32(vec_sxd.val[1], ptrGCoh[0]);
    570       vec_dfwxfw0011 = vmlaq_f32(vec_dfwxfw0011, vec_dfw1, vec_xfw1);
    571       vec_dfwxfw0110 = vmlsq_f32(vec_dfwxfw0110, vec_dfw1, vec_xfw0);
    572       vec_sxd.val[0] = vmlaq_n_f32(vec_sxd.val[0], vec_dfwxfw0011, ptrGCoh[1]);
    573       vec_sxd.val[1] = vmlaq_n_f32(vec_sxd.val[1], vec_dfwxfw0110, ptrGCoh[1]);
    574       vst2q_f32(&aec->sxd[i][0], vec_sxd);
    575     }
    576 
    577     vec_sdSum = vaddq_f32(vec_sdSum, vec_sd);
    578     vec_seSum = vaddq_f32(vec_seSum, vec_se);
    579   }
    580   {
    581     float32x2_t vec_sdSum_total;
    582     float32x2_t vec_seSum_total;
    583     // A B C D
    584     vec_sdSum_total = vpadd_f32(vget_low_f32(vec_sdSum),
    585                                 vget_high_f32(vec_sdSum));
    586     vec_seSum_total = vpadd_f32(vget_low_f32(vec_seSum),
    587                                 vget_high_f32(vec_seSum));
    588     // A+B C+D
    589     vec_sdSum_total = vpadd_f32(vec_sdSum_total, vec_sdSum_total);
    590     vec_seSum_total = vpadd_f32(vec_seSum_total, vec_seSum_total);
    591     // A+B+C+D A+B+C+D
    592     sdSum = vget_lane_f32(vec_sdSum_total, 0);
    593     seSum = vget_lane_f32(vec_seSum_total, 0);
    594   }
    595 
    596   // scalar code for the remaining items.
    597   for (; i < PART_LEN1; i++) {
    598     aec->sd[i] = ptrGCoh[0] * aec->sd[i] +
    599                  ptrGCoh[1] * (dfw[0][i] * dfw[0][i] + dfw[1][i] * dfw[1][i]);
    600     aec->se[i] = ptrGCoh[0] * aec->se[i] +
    601                  ptrGCoh[1] * (efw[0][i] * efw[0][i] + efw[1][i] * efw[1][i]);
    602     // We threshold here to protect against the ill-effects of a zero farend.
    603     // The threshold is not arbitrarily chosen, but balances protection and
    604     // adverse interaction with the algorithm's tuning.
    605     // TODO(bjornv): investigate further why this is so sensitive.
    606     aec->sx[i] =
    607         ptrGCoh[0] * aec->sx[i] +
    608         ptrGCoh[1] * WEBRTC_SPL_MAX(
    609             xfw[0][i] * xfw[0][i] + xfw[1][i] * xfw[1][i],
    610             WebRtcAec_kMinFarendPSD);
    611 
    612     aec->sde[i][0] =
    613         ptrGCoh[0] * aec->sde[i][0] +
    614         ptrGCoh[1] * (dfw[0][i] * efw[0][i] + dfw[1][i] * efw[1][i]);
    615     aec->sde[i][1] =
    616         ptrGCoh[0] * aec->sde[i][1] +
    617         ptrGCoh[1] * (dfw[0][i] * efw[1][i] - dfw[1][i] * efw[0][i]);
    618 
    619     aec->sxd[i][0] =
    620         ptrGCoh[0] * aec->sxd[i][0] +
    621         ptrGCoh[1] * (dfw[0][i] * xfw[0][i] + dfw[1][i] * xfw[1][i]);
    622     aec->sxd[i][1] =
    623         ptrGCoh[0] * aec->sxd[i][1] +
    624         ptrGCoh[1] * (dfw[0][i] * xfw[1][i] - dfw[1][i] * xfw[0][i]);
    625 
    626     sdSum += aec->sd[i];
    627     seSum += aec->se[i];
    628   }
    629 
    630   // Divergent filter safeguard update.
    631   aec->divergeState = (aec->divergeState ? 1.05f : 1.0f) * seSum > sdSum;
    632 
    633   // Signal extreme filter divergence if the error is significantly larger
    634   // than the nearend (13 dB).
    635   *extreme_filter_divergence = (seSum > (19.95f * sdSum));
    636 }
    637 
    638 // Window time domain data to be used by the fft.
    639 static void WindowDataNEON(float* x_windowed, const float* x) {
    640   int i;
    641   for (i = 0; i < PART_LEN; i += 4) {
    642     const float32x4_t vec_Buf1 = vld1q_f32(&x[i]);
    643     const float32x4_t vec_Buf2 = vld1q_f32(&x[PART_LEN + i]);
    644     const float32x4_t vec_sqrtHanning = vld1q_f32(&WebRtcAec_sqrtHanning[i]);
    645     // A B C D
    646     float32x4_t vec_sqrtHanning_rev =
    647         vld1q_f32(&WebRtcAec_sqrtHanning[PART_LEN - i - 3]);
    648     // B A D C
    649     vec_sqrtHanning_rev = vrev64q_f32(vec_sqrtHanning_rev);
    650     // D C B A
    651     vec_sqrtHanning_rev = vcombine_f32(vget_high_f32(vec_sqrtHanning_rev),
    652                                        vget_low_f32(vec_sqrtHanning_rev));
    653     vst1q_f32(&x_windowed[i], vmulq_f32(vec_Buf1, vec_sqrtHanning));
    654     vst1q_f32(&x_windowed[PART_LEN + i],
    655             vmulq_f32(vec_Buf2, vec_sqrtHanning_rev));
    656   }
    657 }
    658 
    659 // Puts fft output data into a complex valued array.
    660 static void StoreAsComplexNEON(const float* data,
    661                                float data_complex[2][PART_LEN1]) {
    662   int i;
    663   for (i = 0; i < PART_LEN; i += 4) {
    664     const float32x4x2_t vec_data = vld2q_f32(&data[2 * i]);
    665     vst1q_f32(&data_complex[0][i], vec_data.val[0]);
    666     vst1q_f32(&data_complex[1][i], vec_data.val[1]);
    667   }
    668   // fix beginning/end values
    669   data_complex[1][0] = 0;
    670   data_complex[1][PART_LEN] = 0;
    671   data_complex[0][0] = data[0];
    672   data_complex[0][PART_LEN] = data[1];
    673 }
    674 
    675 static void SubbandCoherenceNEON(AecCore* aec,
    676                                  float efw[2][PART_LEN1],
    677                                  float dfw[2][PART_LEN1],
    678                                  float xfw[2][PART_LEN1],
    679                                  float* fft,
    680                                  float* cohde,
    681                                  float* cohxd,
    682                                  int* extreme_filter_divergence) {
    683   int i;
    684 
    685   SmoothedPSD(aec, efw, dfw, xfw, extreme_filter_divergence);
    686 
    687   {
    688     const float32x4_t vec_1eminus10 =  vdupq_n_f32(1e-10f);
    689 
    690     // Subband coherence
    691     for (i = 0; i + 3 < PART_LEN1; i += 4) {
    692       const float32x4_t vec_sd = vld1q_f32(&aec->sd[i]);
    693       const float32x4_t vec_se = vld1q_f32(&aec->se[i]);
    694       const float32x4_t vec_sx = vld1q_f32(&aec->sx[i]);
    695       const float32x4_t vec_sdse = vmlaq_f32(vec_1eminus10, vec_sd, vec_se);
    696       const float32x4_t vec_sdsx = vmlaq_f32(vec_1eminus10, vec_sd, vec_sx);
    697       float32x4x2_t vec_sde = vld2q_f32(&aec->sde[i][0]);
    698       float32x4x2_t vec_sxd = vld2q_f32(&aec->sxd[i][0]);
    699       float32x4_t vec_cohde = vmulq_f32(vec_sde.val[0], vec_sde.val[0]);
    700       float32x4_t vec_cohxd = vmulq_f32(vec_sxd.val[0], vec_sxd.val[0]);
    701       vec_cohde = vmlaq_f32(vec_cohde, vec_sde.val[1], vec_sde.val[1]);
    702       vec_cohde = vdivq_f32(vec_cohde, vec_sdse);
    703       vec_cohxd = vmlaq_f32(vec_cohxd, vec_sxd.val[1], vec_sxd.val[1]);
    704       vec_cohxd = vdivq_f32(vec_cohxd, vec_sdsx);
    705 
    706       vst1q_f32(&cohde[i], vec_cohde);
    707       vst1q_f32(&cohxd[i], vec_cohxd);
    708     }
    709   }
    710   // scalar code for the remaining items.
    711   for (; i < PART_LEN1; i++) {
    712     cohde[i] =
    713         (aec->sde[i][0] * aec->sde[i][0] + aec->sde[i][1] * aec->sde[i][1]) /
    714         (aec->sd[i] * aec->se[i] + 1e-10f);
    715     cohxd[i] =
    716         (aec->sxd[i][0] * aec->sxd[i][0] + aec->sxd[i][1] * aec->sxd[i][1]) /
    717         (aec->sx[i] * aec->sd[i] + 1e-10f);
    718   }
    719 }
    720 
    721 void WebRtcAec_InitAec_neon(void) {
    722   WebRtcAec_FilterFar = FilterFarNEON;
    723   WebRtcAec_ScaleErrorSignal = ScaleErrorSignalNEON;
    724   WebRtcAec_FilterAdaptation = FilterAdaptationNEON;
    725   WebRtcAec_OverdriveAndSuppress = OverdriveAndSuppressNEON;
    726   WebRtcAec_SubbandCoherence = SubbandCoherenceNEON;
    727   WebRtcAec_StoreAsComplex = StoreAsComplexNEON;
    728   WebRtcAec_PartitionDelay = PartitionDelayNEON;
    729   WebRtcAec_WindowData = WindowDataNEON;
    730 }
    731