git.gag.com Git - fw/stlink/blob - exampleF4/CMSIS/Documentation/DSP_Lib/html/arm__var__f32_8c_source.html

   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">
   3 <head>
   4 <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
   5 <title>CMSIS DSP Software Library: arm_var_f32.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"/>
  10 </head>
  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');
  15 --></script>
  16 <div class="navigation" id="top">
  17   <div class="tabs">
  18     <ul class="tablist">
  19       <li><a href="index.html"><span>Main&#160;Page</span></a></li>
  20       <li><a href="modules.html"><span>Modules</span></a></li>
  21       <li><a href="annotated.html"><span>Data&#160;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>
  24       <li id="searchli">
  25         <div id="MSearchBox" class="MSearchBoxInactive">
  26         <span class="left">
  27           <img id="MSearchSelect" src="search/mag_sel.png"
  28                onmouseover="return searchBox.OnSearchSelectShow()"
  29                onmouseout="return searchBox.OnSearchSelectHide()"
  30                alt=""/>
  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>
  37           </span>
  38         </div>
  39       </li>
  40     </ul>
  41   </div>
  42   <div class="tabs2">
  43     <ul class="tablist">
  44       <li><a href="files.html"><span>File&#160;List</span></a></li>
  45       <li><a href="globals.html"><span>Globals</span></a></li>
  46     </ul>
  47   </div>
  48 <div class="header">
  49   <div class="headertitle">
  50 <h1>arm_var_f32.c</h1>  </div>
  51 </div>
  52 <div class="contents">
  53 <a href="arm__var__f32_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_var_f32.c   </span>
  61 <a name="l00009"></a>00009 <span class="comment">*   </span>
  62 <a name="l00010"></a>00010 <span class="comment">* Description:  Variance of the elements of a floating-point vector.   </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
  82 <a name="l00030"></a>00030 <span class="preprocessor">#include &quot;<a class="code" href="arm__math_8h.html">arm_math.h</a>&quot;</span>
  83 <a name="l00031"></a>00031
  84 <a name="l00069"></a><a class="code" href="group__variance.html#ga393f26c5a3bfa05624fb8d32232a6d96">00069</a> <span class="keywordtype">void</span> <a class="code" href="group__variance.html#ga393f26c5a3bfa05624fb8d32232a6d96" title="Variance of the elements of a floating-point vector.">arm_var_f32</a>(
  85 <a name="l00070"></a>00070   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> * pSrc,
  86 <a name="l00071"></a>00071   uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>,
  87 <a name="l00072"></a>00072   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> * pResult)
  88 <a name="l00073"></a>00073 {
  89 <a name="l00074"></a>00074
  90 <a name="l00075"></a>00075 <span class="preprocessor">#ifndef ARM_MATH_CM0</span>
  91 <a name="l00076"></a>00076 <span class="preprocessor"></span>
  92 <a name="l00077"></a>00077   <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
  93 <a name="l00078"></a>00078
  94 <a name="l00079"></a>00079   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> sum = (<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) 0.0;               <span class="comment">/* Accumulator */</span>
  95 <a name="l00080"></a>00080   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> meanOfSquares, <a class="code" href="arm__class__marks__example__f32_8c.html#acc9290716b3c97381ce52d14b4b01681">mean</a>, in, squareOfMean;      <span class="comment">/* Temporary variables */</span>
  96 <a name="l00081"></a>00081   uint32_t blkCnt;                               <span class="comment">/* loop counter */</span>
  97 <a name="l00082"></a>00082   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> *pIn;                                <span class="comment">/* Temporary pointer */</span>
  98 <a name="l00083"></a>00083
  99 <a name="l00084"></a>00084   <span class="comment">/* updating temporary pointer */</span>
 100 <a name="l00085"></a>00085   pIn = pSrc;
 101 <a name="l00086"></a>00086
 102 <a name="l00087"></a>00087   <span class="comment">/*loop Unrolling */</span>
 103 <a name="l00088"></a>00088   blkCnt = blockSize &gt;&gt; 2u;
 104 <a name="l00089"></a>00089
 105 <a name="l00090"></a>00090   <span class="comment">/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.   </span>
 106 <a name="l00091"></a>00091 <span class="comment">   ** a second loop below computes the remaining 1 to 3 samples. */</span>
 107 <a name="l00092"></a>00092   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 108 <a name="l00093"></a>00093   {
 109 <a name="l00094"></a>00094     <span class="comment">/* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1])  */</span>
 110 <a name="l00095"></a>00095     <span class="comment">/* Compute Sum of squares of the input samples   </span>
 111 <a name="l00096"></a>00096 <span class="comment">     * and then store the result in a temporary variable, sum. */</span>
 112 <a name="l00097"></a>00097     in = *pSrc++;
 113 <a name="l00098"></a>00098     sum += in * in;
 114 <a name="l00099"></a>00099     in = *pSrc++;
 115 <a name="l00100"></a>00100     sum += in * in;
 116 <a name="l00101"></a>00101     in = *pSrc++;
 117 <a name="l00102"></a>00102     sum += in * in;
 118 <a name="l00103"></a>00103     in = *pSrc++;
 119 <a name="l00104"></a>00104     sum += in * in;
 120 <a name="l00105"></a>00105
 121 <a name="l00106"></a>00106     <span class="comment">/* Decrement the loop counter */</span>
 122 <a name="l00107"></a>00107     blkCnt--;
 123 <a name="l00108"></a>00108   }
 124 <a name="l00109"></a>00109
 125 <a name="l00110"></a>00110   <span class="comment">/* If the blockSize is not a multiple of 4, compute any remaining output samples here.   </span>
 126 <a name="l00111"></a>00111 <span class="comment">   ** No loop unrolling is used. */</span>
 127 <a name="l00112"></a>00112   blkCnt = blockSize % 0x4u;
 128 <a name="l00113"></a>00113
 129 <a name="l00114"></a>00114   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 130 <a name="l00115"></a>00115   {
 131 <a name="l00116"></a>00116     <span class="comment">/* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */</span>
 132 <a name="l00117"></a>00117     <span class="comment">/* Compute Sum of squares of the input samples   </span>
 133 <a name="l00118"></a>00118 <span class="comment">     * and then store the result in a temporary variable, sum. */</span>
 134 <a name="l00119"></a>00119     in = *pSrc++;
 135 <a name="l00120"></a>00120     sum += in * in;
 136 <a name="l00121"></a>00121
 137 <a name="l00122"></a>00122     <span class="comment">/* Decrement the loop counter */</span>
 138 <a name="l00123"></a>00123     blkCnt--;
 139 <a name="l00124"></a>00124   }
 140 <a name="l00125"></a>00125
 141 <a name="l00126"></a>00126   <span class="comment">/* Compute Mean of squares of the input samples   </span>
 142 <a name="l00127"></a>00127 <span class="comment">   * and then store the result in a temporary variable, meanOfSquares. */</span>
 143 <a name="l00128"></a>00128   meanOfSquares = sum / ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) blockSize - 1.0f);
 144 <a name="l00129"></a>00129
 145 <a name="l00130"></a>00130   <span class="comment">/* Reset the accumulator */</span>
 146 <a name="l00131"></a>00131   sum = 0.0f;
 147 <a name="l00132"></a>00132
 148 <a name="l00133"></a>00133   <span class="comment">/*loop Unrolling */</span>
 149 <a name="l00134"></a>00134   blkCnt = blockSize &gt;&gt; 2u;
 150 <a name="l00135"></a>00135
 151 <a name="l00136"></a>00136   <span class="comment">/* Reset the input working pointer */</span>
 152 <a name="l00137"></a>00137   pSrc = pIn;
 153 <a name="l00138"></a>00138
 154 <a name="l00139"></a>00139   <span class="comment">/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.   </span>
 155 <a name="l00140"></a>00140 <span class="comment">   ** a second loop below computes the remaining 1 to 3 samples. */</span>
 156 <a name="l00141"></a>00141   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 157 <a name="l00142"></a>00142   {
 158 <a name="l00143"></a>00143     <span class="comment">/* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */</span>
 159 <a name="l00144"></a>00144     <span class="comment">/* Compute sum of all input values and then store the result in a temporary variable, sum. */</span>
 160 <a name="l00145"></a>00145     sum += *pSrc++;
 161 <a name="l00146"></a>00146     sum += *pSrc++;
 162 <a name="l00147"></a>00147     sum += *pSrc++;
 163 <a name="l00148"></a>00148     sum += *pSrc++;
 164 <a name="l00149"></a>00149
 165 <a name="l00150"></a>00150     <span class="comment">/* Decrement the loop counter */</span>
 166 <a name="l00151"></a>00151     blkCnt--;
 167 <a name="l00152"></a>00152   }
 168 <a name="l00153"></a>00153
 169 <a name="l00154"></a>00154   <span class="comment">/* If the blockSize is not a multiple of 4, compute any remaining output samples here.   </span>
 170 <a name="l00155"></a>00155 <span class="comment">   ** No loop unrolling is used. */</span>
 171 <a name="l00156"></a>00156   blkCnt = blockSize % 0x4u;
 172 <a name="l00157"></a>00157
 173 <a name="l00158"></a>00158   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 174 <a name="l00159"></a>00159   {
 175 <a name="l00160"></a>00160     <span class="comment">/* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */</span>
 176 <a name="l00161"></a>00161     <span class="comment">/* Compute sum of all input values and then store the result in a temporary variable, sum. */</span>
 177 <a name="l00162"></a>00162     sum += *pSrc++;
 178 <a name="l00163"></a>00163
 179 <a name="l00164"></a>00164     <span class="comment">/* Decrement the loop counter */</span>
 180 <a name="l00165"></a>00165     blkCnt--;
 181 <a name="l00166"></a>00166   }
 182 <a name="l00167"></a>00167   <span class="comment">/* Compute mean of all input values */</span>
 183 <a name="l00168"></a>00168   mean = sum / (<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) blockSize;
 184 <a name="l00169"></a>00169
 185 <a name="l00170"></a>00170   <span class="comment">/* Compute square of mean */</span>
 186 <a name="l00171"></a>00171   squareOfMean = (mean * <a class="code" href="arm__class__marks__example__f32_8c.html#acc9290716b3c97381ce52d14b4b01681">mean</a>) * (((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>) /
 187 <a name="l00172"></a>00172                                   ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) blockSize - 1.0f));
 188 <a name="l00173"></a>00173
 189 <a name="l00174"></a>00174   <span class="comment">/* Compute variance and then store the result to the destination */</span>
 190 <a name="l00175"></a>00175   *pResult = meanOfSquares - squareOfMean;
 191 <a name="l00176"></a>00176
 192 <a name="l00177"></a>00177 <span class="preprocessor">#else</span>
 193 <a name="l00178"></a>00178 <span class="preprocessor"></span>
 194 <a name="l00179"></a>00179   <span class="comment">/* Run the below code for Cortex-M0 */</span>
 195 <a name="l00180"></a>00180
 196 <a name="l00181"></a>00181   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> sum = 0.0f;                          <span class="comment">/* Temporary result storage */</span>
 197 <a name="l00182"></a>00182   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> sumOfSquares = 0.0f;                 <span class="comment">/* Sum of squares */</span>
 198 <a name="l00183"></a>00183   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> squareOfSum;                         <span class="comment">/* Square of Sum */</span>
 199 <a name="l00184"></a>00184   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> in;                                  <span class="comment">/* input value */</span>
 200 <a name="l00185"></a>00185   uint32_t blkCnt;                               <span class="comment">/* loop counter */</span>
 201 <a name="l00186"></a>00186
 202 <a name="l00187"></a>00187   <span class="comment">/* Loop over blockSize number of values */</span>
 203 <a name="l00188"></a>00188   blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
 204 <a name="l00189"></a>00189
 205 <a name="l00190"></a>00190   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 206 <a name="l00191"></a>00191   {
 207 <a name="l00192"></a>00192     <span class="comment">/* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */</span>
 208 <a name="l00193"></a>00193     <span class="comment">/* Compute Sum of squares of the input samples    </span>
 209 <a name="l00194"></a>00194 <span class="comment">     * and then store the result in a temporary variable, sumOfSquares. */</span>
 210 <a name="l00195"></a>00195     in = *pSrc++;
 211 <a name="l00196"></a>00196     sumOfSquares += in * in;
 212 <a name="l00197"></a>00197
 213 <a name="l00198"></a>00198     <span class="comment">/* C = (A[0] + A[1] + ... + A[blockSize-1]) */</span>
 214 <a name="l00199"></a>00199     <span class="comment">/* Compute Sum of the input samples    </span>
 215 <a name="l00200"></a>00200 <span class="comment">     * and then store the result in a temporary variable, sum. */</span>
 216 <a name="l00201"></a>00201     sum += in;
 217 <a name="l00202"></a>00202
 218 <a name="l00203"></a>00203     <span class="comment">/* Decrement the loop counter */</span>
 219 <a name="l00204"></a>00204     blkCnt--;
 220 <a name="l00205"></a>00205   }
 221 <a name="l00206"></a>00206
 222 <a name="l00207"></a>00207   <span class="comment">/* Compute the square of sum */</span>
 223 <a name="l00208"></a>00208   squareOfSum = ((sum * sum) / (<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>);
 224 <a name="l00209"></a>00209
 225 <a name="l00210"></a>00210   <span class="comment">/* Compute the variance */</span>
 226 <a name="l00211"></a>00211   *pResult = ((sumOfSquares - squareOfSum) / (<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) (blockSize - 1.0f));
 227 <a name="l00212"></a>00212
 228 <a name="l00213"></a>00213 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
 229 <a name="l00214"></a>00214
 230 <a name="l00215"></a>00215 }
 231 <a name="l00216"></a>00216
 232 </pre></div></div>
 233 </div>
 234 <!--- window showing the filter options -->
 235 <div id="MSearchSelectWindow"
 236      onmouseover="return searchBox.OnSearchSelectShow()"
 237      onmouseout="return searchBox.OnSearchSelectHide()"
 238      onkeydown="return searchBox.OnSearchSelectKey(event)">
 239 <a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark">&#160;</span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark">&#160;</span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark">&#160;</span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark">&#160;</span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark">&#160;</span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark">&#160;</span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark">&#160;</span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark">&#160;</span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark">&#160;</span>Defines</a></div>
 240
 241 <!-- iframe showing the search results (closed by default) -->
 242 <div id="MSearchResultsWindow">
 243 <iframe src="" frameborder="0"
 244         name="MSearchResults" id="MSearchResults">
 245 </iframe>
 246 </div>
 247
 248 <hr class="footer"/><address class="footer"><small>Generated on Fri Jul 15 2011 13:16:17 for CMSIS DSP Software Library by&#160;
 249 <a href="http://www.doxygen.org/index.html">
 250 <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.7.2 </small></address>
 251 </body>
 252 </html>