blob: ff78b5228f447bbb502db6465e459fcafbdf8e5c [file] [log] [blame]
/*
* 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.
*/
/*
* This file contains the function WebRtcSpl_SqrtOfOneMinusXSquared().
* The description header can be found in signal_processing_library.h
*
*/
#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
void WebRtcSpl_SqrtOfOneMinusXSquared(int16_t *xQ15, size_t vector_length,
int16_t *yQ15)
{
int32_t sq;
size_t m;
int16_t tmp;
for (m = 0; m < vector_length; m++)
{
tmp = xQ15[m];
sq = tmp * tmp; // x^2 in Q30
sq = 1073741823 - sq; // 1-x^2, where 1 ~= 0.99999999906 is 1073741823 in Q30
sq = WebRtcSpl_Sqrt(sq); // sqrt(1-x^2) in Q15
yQ15[m] = (int16_t)sq;
}
}