Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2011 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             : /*
      13             :  * This file contains the function WebRtcSpl_SqrtOfOneMinusXSquared().
      14             :  * The description header can be found in signal_processing_library.h
      15             :  *
      16             :  */
      17             : 
      18             : #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
      19             : 
      20           0 : void WebRtcSpl_SqrtOfOneMinusXSquared(int16_t *xQ15, size_t vector_length,
      21             :                                       int16_t *yQ15)
      22             : {
      23             :     int32_t sq;
      24             :     size_t m;
      25             :     int16_t tmp;
      26             : 
      27           0 :     for (m = 0; m < vector_length; m++)
      28             :     {
      29           0 :         tmp = xQ15[m];
      30           0 :         sq = tmp * tmp;  // x^2 in Q30
      31           0 :         sq = 1073741823 - sq; // 1-x^2, where 1 ~= 0.99999999906 is 1073741823 in Q30
      32           0 :         sq = WebRtcSpl_Sqrt(sq); // sqrt(1-x^2) in Q15
      33           0 :         yQ15[m] = (int16_t)sq;
      34             :     }
      35           0 : }