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  50 <h1>arm_q31_to_float.c</h1>  </div>
  51 </div>
  52 <div class="contents">
  53 <a href="arm__q31__to__float_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_q31_to_float.c   </span>
  61 <a name="l00009"></a>00009 <span class="comment">*   </span>
  62 <a name="l00010"></a>00010 <span class="comment">* Description:  Converts the elements of the Q31 vector to 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="l00063"></a><a class="code" href="group__q31__to__x.html#gacf407b007a37da18e99dabd9023c56b4">00063</a> <span class="keywordtype">void</span> <a class="code" href="group__q31__to__x.html#gacf407b007a37da18e99dabd9023c56b4" title="Converts the elements of the Q31 vector to floating-point vector.">arm_q31_to_float</a>(
  85 <a name="l00064"></a>00064   <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> * pSrc,
  86 <a name="l00065"></a>00065   <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> * pDst,
  87 <a name="l00066"></a>00066   uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)
  88 <a name="l00067"></a>00067 {
  89 <a name="l00068"></a>00068   <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">/* Src pointer */</span>
  90 <a name="l00069"></a>00069   uint32_t blkCnt;                               <span class="comment">/* loop counter */</span>
  91 <a name="l00070"></a>00070
  92 <a name="l00071"></a>00071
  93 <a name="l00072"></a>00072 <span class="preprocessor">#ifndef ARM_MATH_CM0</span>
  94 <a name="l00073"></a>00073 <span class="preprocessor"></span>
  95 <a name="l00074"></a>00074   <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
  96 <a name="l00075"></a>00075
  97 <a name="l00076"></a>00076   <span class="comment">/*loop Unrolling */</span>
  98 <a name="l00077"></a>00077   blkCnt = blockSize &gt;&gt; 2u;
  99 <a name="l00078"></a>00078
 100 <a name="l00079"></a>00079   <span class="comment">/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.   </span>
 101 <a name="l00080"></a>00080 <span class="comment">   ** a second loop below computes the remaining 1 to 3 samples. */</span>
 102 <a name="l00081"></a>00081   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 103 <a name="l00082"></a>00082   {
 104 <a name="l00083"></a>00083     <span class="comment">/* C = (float32_t) A / 2147483648 */</span>
 105 <a name="l00084"></a>00084     <span class="comment">/* convert from q31 to float and then store the results in the destination buffer */</span>
 106 <a name="l00085"></a>00085     *pDst++ = ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) * pIn++ / 2147483648.0f);
 107 <a name="l00086"></a>00086     *pDst++ = ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) * pIn++ / 2147483648.0f);
 108 <a name="l00087"></a>00087     *pDst++ = ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) * pIn++ / 2147483648.0f);
 109 <a name="l00088"></a>00088     *pDst++ = ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) * pIn++ / 2147483648.0f);
 110 <a name="l00089"></a>00089
 111 <a name="l00090"></a>00090     <span class="comment">/* Decrement the loop counter */</span>
 112 <a name="l00091"></a>00091     blkCnt--;
 113 <a name="l00092"></a>00092   }
 114 <a name="l00093"></a>00093
 115 <a name="l00094"></a>00094   <span class="comment">/* If the blockSize is not a multiple of 4, compute any remaining output samples here.   </span>
 116 <a name="l00095"></a>00095 <span class="comment">   ** No loop unrolling is used. */</span>
 117 <a name="l00096"></a>00096   blkCnt = blockSize % 0x4u;
 118 <a name="l00097"></a>00097
 119 <a name="l00098"></a>00098 <span class="preprocessor">#else</span>
 120 <a name="l00099"></a>00099 <span class="preprocessor"></span>
 121 <a name="l00100"></a>00100   <span class="comment">/* Run the below code for Cortex-M0 */</span>
 122 <a name="l00101"></a>00101
 123 <a name="l00102"></a>00102   <span class="comment">/* Loop over blockSize number of values */</span>
 124 <a name="l00103"></a>00103   blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
 125 <a name="l00104"></a>00104
 126 <a name="l00105"></a>00105 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
 127 <a name="l00106"></a>00106
 128 <a name="l00107"></a>00107   <span class="keywordflow">while</span>(blkCnt &gt; 0u)
 129 <a name="l00108"></a>00108   {
 130 <a name="l00109"></a>00109     <span class="comment">/* C = (float32_t) A / 2147483648 */</span>
 131 <a name="l00110"></a>00110     <span class="comment">/* convert from q31 to float and then store the results in the destination buffer */</span>
 132 <a name="l00111"></a>00111     *pDst++ = ((<a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a>) * pIn++ / 2147483648.0f);
 133 <a name="l00112"></a>00112
 134 <a name="l00113"></a>00113     <span class="comment">/* Decrement the loop counter */</span>
 135 <a name="l00114"></a>00114     blkCnt--;
 136 <a name="l00115"></a>00115   }
 137 <a name="l00116"></a>00116 }
 138 <a name="l00117"></a>00117
 139 </pre></div></div>
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