1 /* ======================================================================= */
2 /* DSPF_sp_iir_cn.c -- IIR Filter */
3 /* Natural C Implementation */
4 /* */
5 /* Rev 0.0.2 */
6 /* */
7 /* Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ */
8 /* */
9 /* */
10 /* Redistribution and use in source and binary forms, with or without */
11 /* modification, are permitted provided that the following conditions */
12 /* are met: */
13 /* */
14 /* Redistributions of source code must retain the above copyright */
15 /* notice, this list of conditions and the following disclaimer. */
16 /* */
17 /* Redistributions in binary form must reproduce the above copyright */
18 /* notice, this list of conditions and the following disclaimer in the */
19 /* documentation and/or other materials provided with the */
20 /* distribution. */
21 /* */
22 /* Neither the name of Texas Instruments Incorporated nor the names of */
23 /* its contributors may be used to endorse or promote products derived */
24 /* from this software without specific prior written permission. */
25 /* */
26 /* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS */
27 /* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT */
28 /* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR */
29 /* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT */
30 /* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
31 /* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT */
32 /* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, */
33 /* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY */
34 /* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT */
35 /* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE */
36 /* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
37 /* */
38 /* ======================================================================= */
40 #pragma CODE_SECTION(DSPF_sp_iir_cn, ".text:ansi");
42 #include "DSPF_sp_iir_cn.h"
44 void DSPF_sp_iir_cn (float *y1,
45 const float *x,
46 float *y2,
47 const float *hb,
48 const float *ha,
49 int n)
50 {
51 int i, j;
52 float sum;
54 for (i = 0; i < n; i++)
55 {
56 sum = hb[0] * x[4+i];
57 for (j = 1; j <= 4; j++)
58 sum += hb[j] * x[4+i-j] - ha[j] * y1[4+i-j];
60 y1[4+i] = sum;
61 y2[i] = y1[4+i];
62 }
63 }
65 /* ======================================================================= */
66 /* End of file: DSPF_sp_iir_cn.c */
67 /* ----------------------------------------------------------------------- */
68 /* Copyright (c) 2011 Texas Instruments, Incorporated. */
69 /* All Rights Reserved. */
70 /* ======================================================================= */