1 /* 2 ** Copyright 2003-2010, VisualOn, Inc. 3 ** 4 ** Licensed under the Apache License, Version 2.0 (the "License"); 5 ** you may not use this file except in compliance with the License. 6 ** You may obtain a copy of the License at 7 ** 8 ** http://www.apache.org/licenses/LICENSE-2.0 9 ** 10 ** Unless required by applicable law or agreed to in writing, software 11 ** distributed under the License is distributed on an "AS IS" BASIS, 12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 ** See the License for the specific language governing permissions and 14 ** limitations under the License. 15 */ 16 17 /*********************************************************************** 18 * File: residu.c * 19 * * 20 * Description: Compute the LPC residual by filtering * 21 * the input speech through A(z) * 22 * * 23 ************************************************************************/ 24 25 #include "typedef.h" 26 #include "basic_op.h" 27 28 void Residu( 29 Word16 a[], /* (i) Q12 : prediction coefficients */ 30 Word16 x[], /* (i) : speech (values x[-m..-1] are needed */ 31 Word16 y[], /* (o) x2 : residual signal */ 32 Word16 lg /* (i) : size of filtering */ 33 ) 34 { 35 Word16 i,*p1, *p2; 36 Word32 s; 37 for (i = 0; i < lg; i++) 38 { 39 p1 = a; 40 p2 = &x[i]; 41 s = vo_mult32((*p1++), (*p2--)); 42 s += vo_mult32((*p1++), (*p2--)); 43 s += vo_mult32((*p1++), (*p2--)); 44 s += vo_mult32((*p1++), (*p2--)); 45 s += vo_mult32((*p1++), (*p2--)); 46 s += vo_mult32((*p1++), (*p2--)); 47 s += vo_mult32((*p1++), (*p2--)); 48 s += vo_mult32((*p1++), (*p2--)); 49 s += vo_mult32((*p1++), (*p2--)); 50 s += vo_mult32((*p1++), (*p2--)); 51 s += vo_mult32((*p1++), (*p2--)); 52 s += vo_mult32((*p1++), (*p2--)); 53 s += vo_mult32((*p1++), (*p2--)); 54 s += vo_mult32((*p1++), (*p2--)); 55 s += vo_mult32((*p1++), (*p2--)); 56 s += vo_mult32((*p1++), (*p2--)); 57 s += vo_mult32((*p1), (*p2)); 58 59 s = L_shl2(s, 5); 60 y[i] = extract_h(L_add(s, 0x8000)); 61 } 62 63 return; 64 } 65 66 67 68
