| /* |
| * 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; |
| } |
| } |