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_FilterARFastQ12(). 14 * The description header can be found in signal_processing_library.h 15 * 16 */ 17 18 #include "signal_processing_library.h" 19 20 void WebRtcSpl_FilterARFastQ12(WebRtc_Word16 *in, WebRtc_Word16 *out, WebRtc_Word16 *A, 21 WebRtc_Word16 A_length, WebRtc_Word16 length) 22 { 23 WebRtc_Word32 o; 24 int i, j; 25 26 WebRtc_Word16 *x_ptr = &in[0]; 27 WebRtc_Word16 *filtered_ptr = &out[0]; 28 29 for (i = 0; i < length; i++) 30 { 31 // Calculate filtered[i] 32 G_CONST WebRtc_Word16 *a_ptr = &A[0]; 33 WebRtc_Word16 *state_ptr = &out[i - 1]; 34 35 o = WEBRTC_SPL_MUL_16_16(*x_ptr++, *a_ptr++); 36 37 for (j = 1; j < A_length; j++) 38 { 39 o -= WEBRTC_SPL_MUL_16_16(*a_ptr++,*state_ptr--); 40 } 41 42 // Saturate the output 43 o = WEBRTC_SPL_SAT((WebRtc_Word32)134215679, o, (WebRtc_Word32)-134217728); 44 45 *filtered_ptr++ = (WebRtc_Word16)((o + (WebRtc_Word32)2048) >> 12); 46 } 47 48 return; 49 } 50
