1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
2 <html xmlns="http://www.w3.org/1999/xhtml">
4 <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
5 <title>CMSIS DSP Software Library: arm_biquad_cascade_df1_32x64_q31.c Source File</title>
6 <link href="tabs.css" rel="stylesheet" type="text/css"/>
7 <link href="search/search.css" rel="stylesheet" type="text/css"/>
8 <script type="text/javaScript" src="search/search.js"></script>
9 <link href="doxygen.css" rel="stylesheet" type="text/css"/>
11 <body onload='searchBox.OnSelectItem(0);'>
12 <!-- Generated by Doxygen 1.7.2 -->
13 <script type="text/javascript"><!--
14 var searchBox = new SearchBox("searchBox", "search",false,'Search');
16 <div class="navigation" id="top">
19 <li><a href="index.html"><span>Main Page</span></a></li>
20 <li><a href="modules.html"><span>Modules</span></a></li>
21 <li><a href="annotated.html"><span>Data Structures</span></a></li>
22 <li class="current"><a href="files.html"><span>Files</span></a></li>
23 <li><a href="examples.html"><span>Examples</span></a></li>
25 <div id="MSearchBox" class="MSearchBoxInactive">
27 <img id="MSearchSelect" src="search/mag_sel.png"
28 onmouseover="return searchBox.OnSearchSelectShow()"
29 onmouseout="return searchBox.OnSearchSelectHide()"
31 <input type="text" id="MSearchField" value="Search" accesskey="S"
32 onfocus="searchBox.OnSearchFieldFocus(true)"
33 onblur="searchBox.OnSearchFieldFocus(false)"
34 onkeyup="searchBox.OnSearchFieldChange(event)"/>
35 </span><span class="right">
36 <a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
44 <li><a href="files.html"><span>File List</span></a></li>
45 <li><a href="globals.html"><span>Globals</span></a></li>
49 <div class="headertitle">
50 <h1>arm_biquad_cascade_df1_32x64_q31.c</h1> </div>
52 <div class="contents">
53 <a href="arm__biquad__cascade__df1__32x64__q31_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/* ---------------------------------------------------------------------- </span>
54 <a name="l00002"></a>00002 <span class="comment">* Copyright (C) 2010 ARM Limited. All rights reserved. </span>
55 <a name="l00003"></a>00003 <span class="comment">* </span>
56 <a name="l00004"></a>00004 <span class="comment">* $Date: 15. July 2011 </span>
57 <a name="l00005"></a>00005 <span class="comment">* $Revision: V1.0.10 </span>
58 <a name="l00006"></a>00006 <span class="comment">* </span>
59 <a name="l00007"></a>00007 <span class="comment">* Project: CMSIS DSP Library </span>
60 <a name="l00008"></a>00008 <span class="comment">* Title: arm_biquad_cascade_df1_32x64_q31.c </span>
61 <a name="l00009"></a>00009 <span class="comment">* </span>
62 <a name="l00010"></a>00010 <span class="comment">* Description: High precision Q31 Biquad cascade filter processing function </span>
63 <a name="l00011"></a>00011 <span class="comment">* </span>
64 <a name="l00012"></a>00012 <span class="comment">* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0</span>
65 <a name="l00013"></a>00013 <span class="comment">* </span>
66 <a name="l00014"></a>00014 <span class="comment">* Version 1.0.10 2011/7/15 </span>
67 <a name="l00015"></a>00015 <span class="comment">* Big Endian support added and Merged M0 and M3/M4 Source code. </span>
68 <a name="l00016"></a>00016 <span class="comment">* </span>
69 <a name="l00017"></a>00017 <span class="comment">* Version 1.0.3 2010/11/29 </span>
70 <a name="l00018"></a>00018 <span class="comment">* Re-organized the CMSIS folders and updated documentation. </span>
71 <a name="l00019"></a>00019 <span class="comment">* </span>
72 <a name="l00020"></a>00020 <span class="comment">* Version 1.0.2 2010/11/11 </span>
73 <a name="l00021"></a>00021 <span class="comment">* Documentation updated. </span>
74 <a name="l00022"></a>00022 <span class="comment">* </span>
75 <a name="l00023"></a>00023 <span class="comment">* Version 1.0.1 2010/10/05 </span>
76 <a name="l00024"></a>00024 <span class="comment">* Production release and review comments incorporated. </span>
77 <a name="l00025"></a>00025 <span class="comment">* </span>
78 <a name="l00026"></a>00026 <span class="comment">* Version 1.0.0 2010/09/20 </span>
79 <a name="l00027"></a>00027 <span class="comment">* Production release and review comments incorporated. </span>
80 <a name="l00028"></a>00028 <span class="comment">* </span>
81 <a name="l00029"></a>00029 <span class="comment">* Version 0.0.7 2010/06/10 </span>
82 <a name="l00030"></a>00030 <span class="comment">* Misra-C changes done </span>
83 <a name="l00031"></a>00031 <span class="comment">* -------------------------------------------------------------------- */</span>
84 <a name="l00032"></a>00032
85 <a name="l00033"></a>00033 <span class="preprocessor">#include "<a class="code" href="arm__math_8h.html">arm_math.h</a>"</span>
86 <a name="l00034"></a>00034
87 <a name="l00176"></a><a class="code" href="group___biquad_cascade_d_f1__32x64.html#ga953a83e69685de6575cff37feb358a93">00176</a> <span class="keywordtype">void</span> <a class="code" href="group___biquad_cascade_d_f1__32x64.html#ga953a83e69685de6575cff37feb358a93">arm_biquad_cas_df1_32x64_q31</a>(
88 <a name="l00177"></a>00177 <span class="keyword">const</span> <a class="code" href="structarm__biquad__cas__df1__32x64__ins__q31.html" title="Instance structure for the high precision Q31 Biquad cascade filter.">arm_biquad_cas_df1_32x64_ins_q31</a> * S,
89 <a name="l00178"></a>00178 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> * pSrc,
90 <a name="l00179"></a>00179 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> * pDst,
91 <a name="l00180"></a>00180 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)
92 <a name="l00181"></a>00181 {
93 <a name="l00182"></a>00182 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pIn = pSrc; <span class="comment">/* input pointer initialization */</span>
94 <a name="l00183"></a>00183 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pOut = pDst; <span class="comment">/* output pointer initialization */</span>
95 <a name="l00184"></a>00184 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> *pState = S-><a class="code" href="structarm__biquad__cas__df1__32x64__ins__q31.html#a4c899cdfaf2bb955323e93637bd662e0">pState</a>; <span class="comment">/* state pointer initialization */</span>
96 <a name="l00185"></a>00185 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pCoeffs = S-><a class="code" href="structarm__biquad__cas__df1__32x64__ins__q31.html#a490462d6ebe0fecfb6acbf51bed22ecf">pCoeffs</a>; <span class="comment">/* coeff pointer initialization */</span>
97 <a name="l00186"></a>00186 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> acc; <span class="comment">/* accumulator */</span>
98 <a name="l00187"></a>00187 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> Xn1, Xn2, Yn1, Yn2; <span class="comment">/* Filter state variables */</span>
99 <a name="l00188"></a>00188 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> b0, b1, b2, a1, a2; <span class="comment">/* Filter coefficients */</span>
100 <a name="l00189"></a>00189 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> Xn; <span class="comment">/* temporary input */</span>
101 <a name="l00190"></a>00190 int32_t shift = (int32_t) S-><a class="code" href="structarm__biquad__cas__df1__32x64__ins__q31.html#a8e9d58e8dba5aa3b2fc4f36d2ed07996">postShift</a> + 1; <span class="comment">/* Shift to be applied to the output */</span>
102 <a name="l00191"></a>00191 uint32_t sample, stage = S-><a class="code" href="structarm__biquad__cas__df1__32x64__ins__q31.html#ad7cb9a9f5df8f4fcfc7a0b633672e574">numStages</a>; <span class="comment">/* loop counters */</span>
103 <a name="l00192"></a>00192
104 <a name="l00193"></a>00193
105 <a name="l00194"></a>00194 #ifndef ARM_MATH_CM0
106 <a name="l00195"></a>00195
107 <a name="l00196"></a>00196 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
108 <a name="l00197"></a>00197
109 <a name="l00198"></a>00198 <span class="keywordflow">do</span>
110 <a name="l00199"></a>00199 {
111 <a name="l00200"></a>00200 <span class="comment">/* Reading the coefficients */</span>
112 <a name="l00201"></a>00201 b0 = *pCoeffs++;
113 <a name="l00202"></a>00202 b1 = *pCoeffs++;
114 <a name="l00203"></a>00203 b2 = *pCoeffs++;
115 <a name="l00204"></a>00204 a1 = *pCoeffs++;
116 <a name="l00205"></a>00205 a2 = *pCoeffs++;
117 <a name="l00206"></a>00206
118 <a name="l00207"></a>00207 <span class="comment">/* Reading the state values */</span>
119 <a name="l00208"></a>00208 Xn1 = pState[0];
120 <a name="l00209"></a>00209 Xn2 = pState[1];
121 <a name="l00210"></a>00210 Yn1 = pState[2];
122 <a name="l00211"></a>00211 Yn2 = pState[3];
123 <a name="l00212"></a>00212
124 <a name="l00213"></a>00213 <span class="comment">/* Apply loop unrolling and compute 4 output values simultaneously. */</span>
125 <a name="l00214"></a>00214 <span class="comment">/* The variable acc hold output value that is being computed and </span>
126 <a name="l00215"></a>00215 <span class="comment"> * stored in the destination buffer </span>
127 <a name="l00216"></a>00216 <span class="comment"> * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] </span>
128 <a name="l00217"></a>00217 <span class="comment"> */</span>
129 <a name="l00218"></a>00218
130 <a name="l00219"></a>00219 sample = blockSize >> 2u;
131 <a name="l00220"></a>00220
132 <a name="l00221"></a>00221 <span class="comment">/* First part of the processing with loop unrolling. Compute 4 outputs at a time. </span>
133 <a name="l00222"></a>00222 <span class="comment"> ** a second loop below computes the remaining 1 to 3 samples. */</span>
134 <a name="l00223"></a>00223 <span class="keywordflow">while</span>(sample > 0u)
135 <a name="l00224"></a>00224 {
136 <a name="l00225"></a>00225 <span class="comment">/* Read the input */</span>
137 <a name="l00226"></a>00226 Xn = *pIn++;
138 <a name="l00227"></a>00227
139 <a name="l00228"></a>00228 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span>
140 <a name="l00229"></a>00229 Xn = Xn << 32;
141 <a name="l00230"></a>00230
142 <a name="l00231"></a>00231 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
143 <a name="l00232"></a>00232
144 <a name="l00233"></a>00233 <span class="comment">/* acc = b0 * x[n] */</span>
145 <a name="l00234"></a>00234 acc = <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn, b0);
146 <a name="l00235"></a>00235 <span class="comment">/* acc += b1 * x[n-1] */</span>
147 <a name="l00236"></a>00236 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn1, b1);
148 <a name="l00237"></a>00237 <span class="comment">/* acc += b[2] * x[n-2] */</span>
149 <a name="l00238"></a>00238 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn2, b2);
150 <a name="l00239"></a>00239 <span class="comment">/* acc += a1 * y[n-1] */</span>
151 <a name="l00240"></a>00240 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn1, a1);
152 <a name="l00241"></a>00241 <span class="comment">/* acc += a2 * y[n-2] */</span>
153 <a name="l00242"></a>00242 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn2, a2);
154 <a name="l00243"></a>00243
155 <a name="l00244"></a>00244 <span class="comment">/* The result is converted to 1.63 , Yn2 variable is reused */</span>
156 <a name="l00245"></a>00245 Yn2 = acc << shift;
157 <a name="l00246"></a>00246
158 <a name="l00247"></a>00247 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span>
159 <a name="l00248"></a>00248 *pOut++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> (32 - shift));
160 <a name="l00249"></a>00249
161 <a name="l00250"></a>00250 <span class="comment">/* Read the second input into Xn2, to reuse the value */</span>
162 <a name="l00251"></a>00251 Xn2 = *pIn++;
163 <a name="l00252"></a>00252
164 <a name="l00253"></a>00253 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span>
165 <a name="l00254"></a>00254 Xn2 = Xn2 << 32;
166 <a name="l00255"></a>00255
167 <a name="l00256"></a>00256 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
168 <a name="l00257"></a>00257
169 <a name="l00258"></a>00258 <span class="comment">/* acc = b0 * x[n] */</span>
170 <a name="l00259"></a>00259 acc = <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn2, b0);
171 <a name="l00260"></a>00260 <span class="comment">/* acc += b1 * x[n-1] */</span>
172 <a name="l00261"></a>00261 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn, b1);
173 <a name="l00262"></a>00262 <span class="comment">/* acc += b[2] * x[n-2] */</span>
174 <a name="l00263"></a>00263 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn1, b2);
175 <a name="l00264"></a>00264 <span class="comment">/* acc += a1 * y[n-1] */</span>
176 <a name="l00265"></a>00265 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn2, a1);
177 <a name="l00266"></a>00266 <span class="comment">/* acc += a2 * y[n-2] */</span>
178 <a name="l00267"></a>00267 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn1, a2);
179 <a name="l00268"></a>00268
180 <a name="l00269"></a>00269 <span class="comment">/* The result is converted to 1.63, Yn1 variable is reused */</span>
181 <a name="l00270"></a>00270 Yn1 = acc << shift;
182 <a name="l00271"></a>00271
183 <a name="l00272"></a>00272 <span class="comment">/* The result is converted to 1.31 */</span>
184 <a name="l00273"></a>00273 <span class="comment">/* Store the output in the destination buffer. */</span>
185 <a name="l00274"></a>00274 *pOut++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> (32 - shift));
186 <a name="l00275"></a>00275
187 <a name="l00276"></a>00276 <span class="comment">/* Read the third input into Xn1, to reuse the value */</span>
188 <a name="l00277"></a>00277 Xn1 = *pIn++;
189 <a name="l00278"></a>00278
190 <a name="l00279"></a>00279 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span>
191 <a name="l00280"></a>00280 Xn1 = Xn1 << 32;
192 <a name="l00281"></a>00281
193 <a name="l00282"></a>00282 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
194 <a name="l00283"></a>00283 <span class="comment">/* acc = b0 * x[n] */</span>
195 <a name="l00284"></a>00284 acc = <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn1, b0);
196 <a name="l00285"></a>00285 <span class="comment">/* acc += b1 * x[n-1] */</span>
197 <a name="l00286"></a>00286 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn2, b1);
198 <a name="l00287"></a>00287 <span class="comment">/* acc += b[2] * x[n-2] */</span>
199 <a name="l00288"></a>00288 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn, b2);
200 <a name="l00289"></a>00289 <span class="comment">/* acc += a1 * y[n-1] */</span>
201 <a name="l00290"></a>00290 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn1, a1);
202 <a name="l00291"></a>00291 <span class="comment">/* acc += a2 * y[n-2] */</span>
203 <a name="l00292"></a>00292 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn2, a2);
204 <a name="l00293"></a>00293
205 <a name="l00294"></a>00294 <span class="comment">/* The result is converted to 1.63, Yn2 variable is reused */</span>
206 <a name="l00295"></a>00295 Yn2 = acc << shift;
207 <a name="l00296"></a>00296
208 <a name="l00297"></a>00297 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span>
209 <a name="l00298"></a>00298 *pOut++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> (32 - shift));
210 <a name="l00299"></a>00299
211 <a name="l00300"></a>00300 <span class="comment">/* Read the fourth input into Xn, to reuse the value */</span>
212 <a name="l00301"></a>00301 Xn = *pIn++;
213 <a name="l00302"></a>00302
214 <a name="l00303"></a>00303 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span>
215 <a name="l00304"></a>00304 Xn = Xn << 32;
216 <a name="l00305"></a>00305
217 <a name="l00306"></a>00306 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
218 <a name="l00307"></a>00307 <span class="comment">/* acc = b0 * x[n] */</span>
219 <a name="l00308"></a>00308 acc = <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn, b0);
220 <a name="l00309"></a>00309 <span class="comment">/* acc += b1 * x[n-1] */</span>
221 <a name="l00310"></a>00310 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn1, b1);
222 <a name="l00311"></a>00311 <span class="comment">/* acc += b[2] * x[n-2] */</span>
223 <a name="l00312"></a>00312 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn2, b2);
224 <a name="l00313"></a>00313 <span class="comment">/* acc += a1 * y[n-1] */</span>
225 <a name="l00314"></a>00314 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn2, a1);
226 <a name="l00315"></a>00315 <span class="comment">/* acc += a2 * y[n-2] */</span>
227 <a name="l00316"></a>00316 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn1, a2);
228 <a name="l00317"></a>00317
229 <a name="l00318"></a>00318 <span class="comment">/* The result is converted to 1.63, Yn1 variable is reused */</span>
230 <a name="l00319"></a>00319 Yn1 = acc << shift;
231 <a name="l00320"></a>00320
232 <a name="l00321"></a>00321 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
233 <a name="l00322"></a>00322 <span class="comment">/* The states should be updated as: */</span>
234 <a name="l00323"></a>00323 <span class="comment">/* Xn2 = Xn1 */</span>
235 <a name="l00324"></a>00324 <span class="comment">/* Xn1 = Xn */</span>
236 <a name="l00325"></a>00325 <span class="comment">/* Yn2 = Yn1 */</span>
237 <a name="l00326"></a>00326 <span class="comment">/* Yn1 = acc */</span>
238 <a name="l00327"></a>00327 Xn2 = Xn1;
239 <a name="l00328"></a>00328 Xn1 = Xn;
240 <a name="l00329"></a>00329
241 <a name="l00330"></a>00330 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span>
242 <a name="l00331"></a>00331 *pOut++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> (32 - shift));
243 <a name="l00332"></a>00332
244 <a name="l00333"></a>00333 <span class="comment">/* decrement the loop counter */</span>
245 <a name="l00334"></a>00334 sample--;
246 <a name="l00335"></a>00335 }
247 <a name="l00336"></a>00336
248 <a name="l00337"></a>00337 <span class="comment">/* If the blockSize is not a multiple of 4, compute any remaining output samples here. </span>
249 <a name="l00338"></a>00338 <span class="comment"> ** No loop unrolling is used. */</span>
250 <a name="l00339"></a>00339 sample = (blockSize & 0x3u);
251 <a name="l00340"></a>00340
252 <a name="l00341"></a>00341 <span class="keywordflow">while</span>(sample > 0u)
253 <a name="l00342"></a>00342 {
254 <a name="l00343"></a>00343 <span class="comment">/* Read the input */</span>
255 <a name="l00344"></a>00344 Xn = *pIn++;
256 <a name="l00345"></a>00345
257 <a name="l00346"></a>00346 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span>
258 <a name="l00347"></a>00347 Xn = Xn << 32;
259 <a name="l00348"></a>00348
260 <a name="l00349"></a>00349 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
261 <a name="l00350"></a>00350 <span class="comment">/* acc = b0 * x[n] */</span>
262 <a name="l00351"></a>00351 acc = <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn, b0);
263 <a name="l00352"></a>00352 <span class="comment">/* acc += b1 * x[n-1] */</span>
264 <a name="l00353"></a>00353 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn1, b1);
265 <a name="l00354"></a>00354 <span class="comment">/* acc += b[2] * x[n-2] */</span>
266 <a name="l00355"></a>00355 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn2, b2);
267 <a name="l00356"></a>00356 <span class="comment">/* acc += a1 * y[n-1] */</span>
268 <a name="l00357"></a>00357 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn1, a1);
269 <a name="l00358"></a>00358 <span class="comment">/* acc += a2 * y[n-2] */</span>
270 <a name="l00359"></a>00359 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn2, a2);
271 <a name="l00360"></a>00360
272 <a name="l00361"></a>00361 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
273 <a name="l00362"></a>00362 <span class="comment">/* The states should be updated as: */</span>
274 <a name="l00363"></a>00363 <span class="comment">/* Xn2 = Xn1 */</span>
275 <a name="l00364"></a>00364 <span class="comment">/* Xn1 = Xn */</span>
276 <a name="l00365"></a>00365 <span class="comment">/* Yn2 = Yn1 */</span>
277 <a name="l00366"></a>00366 <span class="comment">/* Yn1 = acc */</span>
278 <a name="l00367"></a>00367 Xn2 = Xn1;
279 <a name="l00368"></a>00368 Xn1 = Xn;
280 <a name="l00369"></a>00369 Yn2 = Yn1;
281 <a name="l00370"></a>00370 Yn1 = acc << shift;
282 <a name="l00371"></a>00371
283 <a name="l00372"></a>00372 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span>
284 <a name="l00373"></a>00373 *pOut++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> (32 - shift));
285 <a name="l00374"></a>00374
286 <a name="l00375"></a>00375 <span class="comment">/* decrement the loop counter */</span>
287 <a name="l00376"></a>00376 sample--;
288 <a name="l00377"></a>00377 }
289 <a name="l00378"></a>00378
290 <a name="l00379"></a>00379 <span class="comment">/* The first stage output is given as input to the second stage. */</span>
291 <a name="l00380"></a>00380 pIn = pDst;
292 <a name="l00381"></a>00381
293 <a name="l00382"></a>00382 <span class="comment">/* Reset to destination buffer working pointer */</span>
294 <a name="l00383"></a>00383 pOut = pDst;
295 <a name="l00384"></a>00384
296 <a name="l00385"></a>00385 <span class="comment">/* Store the updated state variables back into the pState array */</span>
297 <a name="l00386"></a>00386 *pState++ = Xn1;
298 <a name="l00387"></a>00387 *pState++ = Xn2;
299 <a name="l00388"></a>00388 *pState++ = Yn1;
300 <a name="l00389"></a>00389 *pState++ = Yn2;
301 <a name="l00390"></a>00390
302 <a name="l00391"></a>00391 } <span class="keywordflow">while</span>(--stage);
303 <a name="l00392"></a>00392
304 <a name="l00393"></a>00393 <span class="preprocessor">#else</span>
305 <a name="l00394"></a>00394 <span class="preprocessor"></span>
306 <a name="l00395"></a>00395 <span class="comment">/* Run the below code for Cortex-M0 */</span>
307 <a name="l00396"></a>00396
308 <a name="l00397"></a>00397 <span class="keywordflow">do</span>
309 <a name="l00398"></a>00398 {
310 <a name="l00399"></a>00399 <span class="comment">/* Reading the coefficients */</span>
311 <a name="l00400"></a>00400 b0 = *pCoeffs++;
312 <a name="l00401"></a>00401 b1 = *pCoeffs++;
313 <a name="l00402"></a>00402 b2 = *pCoeffs++;
314 <a name="l00403"></a>00403 a1 = *pCoeffs++;
315 <a name="l00404"></a>00404 a2 = *pCoeffs++;
316 <a name="l00405"></a>00405
317 <a name="l00406"></a>00406 <span class="comment">/* Reading the state values */</span>
318 <a name="l00407"></a>00407 Xn1 = pState[0];
319 <a name="l00408"></a>00408 Xn2 = pState[1];
320 <a name="l00409"></a>00409 Yn1 = pState[2];
321 <a name="l00410"></a>00410 Yn2 = pState[3];
322 <a name="l00411"></a>00411
323 <a name="l00412"></a>00412 <span class="comment">/* The variable acc hold output value that is being computed and </span>
324 <a name="l00413"></a>00413 <span class="comment"> * stored in the destination buffer </span>
325 <a name="l00414"></a>00414 <span class="comment"> * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] </span>
326 <a name="l00415"></a>00415 <span class="comment"> */</span>
327 <a name="l00416"></a>00416
328 <a name="l00417"></a>00417 sample = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
329 <a name="l00418"></a>00418
330 <a name="l00419"></a>00419 <span class="keywordflow">while</span>(sample > 0u)
331 <a name="l00420"></a>00420 {
332 <a name="l00421"></a>00421 <span class="comment">/* Read the input */</span>
333 <a name="l00422"></a>00422 Xn = *pIn++;
334 <a name="l00423"></a>00423
335 <a name="l00424"></a>00424 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span>
336 <a name="l00425"></a>00425 Xn = Xn << 32;
337 <a name="l00426"></a>00426
338 <a name="l00427"></a>00427 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
339 <a name="l00428"></a>00428 <span class="comment">/* acc = b0 * x[n] */</span>
340 <a name="l00429"></a>00429 acc = <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn, b0);
341 <a name="l00430"></a>00430 <span class="comment">/* acc += b1 * x[n-1] */</span>
342 <a name="l00431"></a>00431 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn1, b1);
343 <a name="l00432"></a>00432 <span class="comment">/* acc += b[2] * x[n-2] */</span>
344 <a name="l00433"></a>00433 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Xn2, b2);
345 <a name="l00434"></a>00434 <span class="comment">/* acc += a1 * y[n-1] */</span>
346 <a name="l00435"></a>00435 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn1, a1);
347 <a name="l00436"></a>00436 <span class="comment">/* acc += a2 * y[n-2] */</span>
348 <a name="l00437"></a>00437 acc += <a class="code" href="arm__math_8h.html#a642a29d71f7951a7f6c0b797c300b711" title="Multiplies 32 X 64 and returns 32 bit result in 2.30 format.">mult32x64</a>(Yn2, a2);
349 <a name="l00438"></a>00438
350 <a name="l00439"></a>00439 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
351 <a name="l00440"></a>00440 <span class="comment">/* The states should be updated as: */</span>
352 <a name="l00441"></a>00441 <span class="comment">/* Xn2 = Xn1 */</span>
353 <a name="l00442"></a>00442 <span class="comment">/* Xn1 = Xn */</span>
354 <a name="l00443"></a>00443 <span class="comment">/* Yn2 = Yn1 */</span>
355 <a name="l00444"></a>00444 <span class="comment">/* Yn1 = acc */</span>
356 <a name="l00445"></a>00445 Xn2 = Xn1;
357 <a name="l00446"></a>00446 Xn1 = Xn;
358 <a name="l00447"></a>00447 Yn2 = Yn1;
359 <a name="l00448"></a>00448 Yn1 = acc << shift;
360 <a name="l00449"></a>00449
361 <a name="l00450"></a>00450 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span>
362 <a name="l00451"></a>00451 *pOut++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> (32 - shift));
363 <a name="l00452"></a>00452
364 <a name="l00453"></a>00453 <span class="comment">/* decrement the loop counter */</span>
365 <a name="l00454"></a>00454 sample--;
366 <a name="l00455"></a>00455 }
367 <a name="l00456"></a>00456
368 <a name="l00457"></a>00457 <span class="comment">/* The first stage output is given as input to the second stage. */</span>
369 <a name="l00458"></a>00458 pIn = pDst;
370 <a name="l00459"></a>00459
371 <a name="l00460"></a>00460 <span class="comment">/* Reset to destination buffer working pointer */</span>
372 <a name="l00461"></a>00461 pOut = pDst;
373 <a name="l00462"></a>00462
374 <a name="l00463"></a>00463 <span class="comment">/* Store the updated state variables back into the pState array */</span>
375 <a name="l00464"></a>00464 *pState++ = Xn1;
376 <a name="l00465"></a>00465 *pState++ = Xn2;
377 <a name="l00466"></a>00466 *pState++ = Yn1;
378 <a name="l00467"></a>00467 *pState++ = Yn2;
379 <a name="l00468"></a>00468
380 <a name="l00469"></a>00469 } <span class="keywordflow">while</span>(--stage);
381 <a name="l00470"></a>00470
382 <a name="l00471"></a>00471 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
383 <a name="l00472"></a>00472 }
384 <a name="l00473"></a>00473
387 <!--- window showing the filter options -->
388 <div id="MSearchSelectWindow"
389 onmouseover="return searchBox.OnSearchSelectShow()"
390 onmouseout="return searchBox.OnSearchSelectHide()"
391 onkeydown="return searchBox.OnSearchSelectKey(event)">
392 <a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark"> </span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark"> </span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark"> </span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark"> </span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark"> </span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark"> </span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark"> </span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark"> </span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark"> </span>Defines</a></div>
394 <!-- iframe showing the search results (closed by default) -->
395 <div id="MSearchResultsWindow">
396 <iframe src="" frameborder="0"
397 name="MSearchResults" id="MSearchResults">
401 <hr class="footer"/><address class="footer"><small>Generated on Fri Jul 15 2011 13:16:15 for CMSIS DSP Software Library by 
402 <a href="http://www.doxygen.org/index.html">
403 <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.7.2 </small></address>
projects / fw / stlink / blob