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| <h1>arm_fir_interpolate_q31.c</h1> </div> |
| </div> |
| <div class="contents"> |
| <a href="arm__fir__interpolate__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> |
| <a name="l00002"></a>00002 <span class="comment">* Copyright (C) 2010 ARM Limited. All rights reserved. </span> |
| <a name="l00003"></a>00003 <span class="comment">* </span> |
| <a name="l00004"></a>00004 <span class="comment">* $Date: 15. July 2011 </span> |
| <a name="l00005"></a>00005 <span class="comment">* $Revision: V1.0.10 </span> |
| <a name="l00006"></a>00006 <span class="comment">* </span> |
| <a name="l00007"></a>00007 <span class="comment">* Project: CMSIS DSP Library </span> |
| <a name="l00008"></a>00008 <span class="comment">* Title: arm_fir_interpolate_q31.c </span> |
| <a name="l00009"></a>00009 <span class="comment">* </span> |
| <a name="l00010"></a>00010 <span class="comment">* Description: Q31 FIR interpolation. </span> |
| <a name="l00011"></a>00011 <span class="comment">* </span> |
| <a name="l00012"></a>00012 <span class="comment">* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0</span> |
| <a name="l00013"></a>00013 <span class="comment">* </span> |
| <a name="l00014"></a>00014 <span class="comment">* Version 1.0.10 2011/7/15 </span> |
| <a name="l00015"></a>00015 <span class="comment">* Big Endian support added and Merged M0 and M3/M4 Source code. </span> |
| <a name="l00016"></a>00016 <span class="comment">* </span> |
| <a name="l00017"></a>00017 <span class="comment">* Version 1.0.3 2010/11/29 </span> |
| <a name="l00018"></a>00018 <span class="comment">* Re-organized the CMSIS folders and updated documentation. </span> |
| <a name="l00019"></a>00019 <span class="comment">* </span> |
| <a name="l00020"></a>00020 <span class="comment">* Version 1.0.2 2010/11/11 </span> |
| <a name="l00021"></a>00021 <span class="comment">* Documentation updated. </span> |
| <a name="l00022"></a>00022 <span class="comment">* </span> |
| <a name="l00023"></a>00023 <span class="comment">* Version 1.0.1 2010/10/05 </span> |
| <a name="l00024"></a>00024 <span class="comment">* Production release and review comments incorporated. </span> |
| <a name="l00025"></a>00025 <span class="comment">* </span> |
| <a name="l00026"></a>00026 <span class="comment">* Version 1.0.0 2010/09/20 </span> |
| <a name="l00027"></a>00027 <span class="comment">* Production release and review comments incorporated </span> |
| <a name="l00028"></a>00028 <span class="comment">* </span> |
| <a name="l00029"></a>00029 <span class="comment">* Version 0.0.7 2010/06/10 </span> |
| <a name="l00030"></a>00030 <span class="comment">* Misra-C changes done </span> |
| <a name="l00031"></a>00031 <span class="comment">* ---------------------------------------------------------------------------*/</span> |
| <a name="l00032"></a>00032 |
| <a name="l00033"></a>00033 <span class="preprocessor">#include "<a class="code" href="arm__math_8h.html">arm_math.h</a>"</span> |
| <a name="l00034"></a>00034 |
| <a name="l00063"></a><a class="code" href="group___f_i_r___interpolate.html#gaac9c0f01ed91c53f7083995d7411f5ee">00063</a> <span class="keywordtype">void</span> <a class="code" href="group___f_i_r___interpolate.html#gaac9c0f01ed91c53f7083995d7411f5ee" title="Processing function for the Q31 FIR interpolator.">arm_fir_interpolate_q31</a>( |
| <a name="l00064"></a>00064 <span class="keyword">const</span> <a class="code" href="structarm__fir__interpolate__instance__q31.html" title="Instance structure for the Q31 FIR interpolator.">arm_fir_interpolate_instance_q31</a> * S, |
| <a name="l00065"></a>00065 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> * pSrc, |
| <a name="l00066"></a>00066 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> * pDst, |
| <a name="l00067"></a>00067 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>) |
| <a name="l00068"></a>00068 { |
| <a name="l00069"></a>00069 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pState = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a>; <span class="comment">/* State pointer */</span> |
| <a name="l00070"></a>00070 <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__fir__interpolate__instance__q31.html#afa719433687e1936ec3403d0d32f06e6">pCoeffs</a>; <span class="comment">/* Coefficient pointer */</span> |
| <a name="l00071"></a>00071 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pStateCurnt; <span class="comment">/* Points to the current sample of the state */</span> |
| <a name="l00072"></a>00072 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *ptr1, *ptr2; <span class="comment">/* Temporary pointers for state and coefficient buffers */</span> |
| <a name="l00073"></a>00073 |
| <a name="l00074"></a>00074 <span class="preprocessor">#ifndef ARM_MATH_CM0</span> |
| <a name="l00075"></a>00075 <span class="preprocessor"></span> |
| <a name="l00076"></a>00076 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span> |
| <a name="l00077"></a>00077 |
| <a name="l00078"></a>00078 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> sum0; <span class="comment">/* Accumulators */</span> |
| <a name="l00079"></a>00079 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> x0, c0; <span class="comment">/* Temporary variables to hold state and coefficient values */</span> |
| <a name="l00080"></a>00080 uint32_t i, blkCnt, j; <span class="comment">/* Loop counters */</span> |
| <a name="l00081"></a>00081 uint16_t phaseLen = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5d243796584afc7cd6c557f00b7acca5">phaseLength</a>, tapCnt; <span class="comment">/* Length of each polyphase filter component */</span> |
| <a name="l00082"></a>00082 |
| <a name="l00083"></a>00083 |
| <a name="l00084"></a>00084 <span class="comment">/* S->pState buffer contains previous frame (phaseLen - 1) samples */</span> |
| <a name="l00085"></a>00085 <span class="comment">/* pStateCurnt points to the location where the new input data should be written */</span> |
| <a name="l00086"></a>00086 pStateCurnt = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a> + ((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) phaseLen - 1); |
| <a name="l00087"></a>00087 |
| <a name="l00088"></a>00088 <span class="comment">/* Total number of intput samples */</span> |
| <a name="l00089"></a>00089 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>; |
| <a name="l00090"></a>00090 |
| <a name="l00091"></a>00091 <span class="comment">/* Loop over the blockSize. */</span> |
| <a name="l00092"></a>00092 <span class="keywordflow">while</span>(blkCnt > 0u) |
| <a name="l00093"></a>00093 { |
| <a name="l00094"></a>00094 <span class="comment">/* Copy new input sample into the state buffer */</span> |
| <a name="l00095"></a>00095 *pStateCurnt++ = *pSrc++; |
| <a name="l00096"></a>00096 |
| <a name="l00097"></a>00097 <span class="comment">/* Address modifier index of coefficient buffer */</span> |
| <a name="l00098"></a>00098 j = 1u; |
| <a name="l00099"></a>00099 |
| <a name="l00100"></a>00100 <span class="comment">/* Loop over the Interpolation factor. */</span> |
| <a name="l00101"></a>00101 i = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00102"></a>00102 <span class="keywordflow">while</span>(i > 0u) |
| <a name="l00103"></a>00103 { |
| <a name="l00104"></a>00104 <span class="comment">/* Set accumulator to zero */</span> |
| <a name="l00105"></a>00105 sum0 = 0; |
| <a name="l00106"></a>00106 |
| <a name="l00107"></a>00107 <span class="comment">/* Initialize state pointer */</span> |
| <a name="l00108"></a>00108 ptr1 = pState; |
| <a name="l00109"></a>00109 |
| <a name="l00110"></a>00110 <span class="comment">/* Initialize coefficient pointer */</span> |
| <a name="l00111"></a>00111 ptr2 = pCoeffs + (S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a> - j); |
| <a name="l00112"></a>00112 |
| <a name="l00113"></a>00113 <span class="comment">/* Loop over the polyPhase length. Unroll by a factor of 4. </span> |
| <a name="l00114"></a>00114 <span class="comment"> ** Repeat until we've computed numTaps-(4*S->L) coefficients. */</span> |
| <a name="l00115"></a>00115 tapCnt = phaseLen >> 2; |
| <a name="l00116"></a>00116 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00117"></a>00117 { |
| <a name="l00118"></a>00118 |
| <a name="l00119"></a>00119 <span class="comment">/* Read the coefficient */</span> |
| <a name="l00120"></a>00120 c0 = *(ptr2); |
| <a name="l00121"></a>00121 |
| <a name="l00122"></a>00122 <span class="comment">/* Upsampling is done by stuffing L-1 zeros between each sample. </span> |
| <a name="l00123"></a>00123 <span class="comment"> * So instead of multiplying zeros with coefficients, </span> |
| <a name="l00124"></a>00124 <span class="comment"> * Increment the coefficient pointer by interpolation factor times. */</span> |
| <a name="l00125"></a>00125 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00126"></a>00126 |
| <a name="l00127"></a>00127 <span class="comment">/* Read the input sample */</span> |
| <a name="l00128"></a>00128 x0 = *(ptr1++); |
| <a name="l00129"></a>00129 |
| <a name="l00130"></a>00130 <span class="comment">/* Perform the multiply-accumulate */</span> |
| <a name="l00131"></a>00131 sum0 += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) x0 *c0; |
| <a name="l00132"></a>00132 |
| <a name="l00133"></a>00133 <span class="comment">/* Read the coefficient */</span> |
| <a name="l00134"></a>00134 c0 = *(ptr2); |
| <a name="l00135"></a>00135 |
| <a name="l00136"></a>00136 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span> |
| <a name="l00137"></a>00137 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00138"></a>00138 |
| <a name="l00139"></a>00139 <span class="comment">/* Read the input sample */</span> |
| <a name="l00140"></a>00140 x0 = *(ptr1++); |
| <a name="l00141"></a>00141 |
| <a name="l00142"></a>00142 <span class="comment">/* Perform the multiply-accumulate */</span> |
| <a name="l00143"></a>00143 sum0 += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) x0 *c0; |
| <a name="l00144"></a>00144 |
| <a name="l00145"></a>00145 <span class="comment">/* Read the coefficient */</span> |
| <a name="l00146"></a>00146 c0 = *(ptr2); |
| <a name="l00147"></a>00147 |
| <a name="l00148"></a>00148 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span> |
| <a name="l00149"></a>00149 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00150"></a>00150 |
| <a name="l00151"></a>00151 <span class="comment">/* Read the input sample */</span> |
| <a name="l00152"></a>00152 x0 = *(ptr1++); |
| <a name="l00153"></a>00153 |
| <a name="l00154"></a>00154 <span class="comment">/* Perform the multiply-accumulate */</span> |
| <a name="l00155"></a>00155 sum0 += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) x0 *c0; |
| <a name="l00156"></a>00156 |
| <a name="l00157"></a>00157 <span class="comment">/* Read the coefficient */</span> |
| <a name="l00158"></a>00158 c0 = *(ptr2); |
| <a name="l00159"></a>00159 |
| <a name="l00160"></a>00160 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span> |
| <a name="l00161"></a>00161 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00162"></a>00162 |
| <a name="l00163"></a>00163 <span class="comment">/* Read the input sample */</span> |
| <a name="l00164"></a>00164 x0 = *(ptr1++); |
| <a name="l00165"></a>00165 |
| <a name="l00166"></a>00166 <span class="comment">/* Perform the multiply-accumulate */</span> |
| <a name="l00167"></a>00167 sum0 += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) x0 *c0; |
| <a name="l00168"></a>00168 |
| <a name="l00169"></a>00169 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00170"></a>00170 tapCnt--; |
| <a name="l00171"></a>00171 } |
| <a name="l00172"></a>00172 |
| <a name="l00173"></a>00173 <span class="comment">/* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */</span> |
| <a name="l00174"></a>00174 tapCnt = phaseLen & 0x3u; |
| <a name="l00175"></a>00175 |
| <a name="l00176"></a>00176 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00177"></a>00177 { |
| <a name="l00178"></a>00178 <span class="comment">/* Read the coefficient */</span> |
| <a name="l00179"></a>00179 c0 = *(ptr2); |
| <a name="l00180"></a>00180 |
| <a name="l00181"></a>00181 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span> |
| <a name="l00182"></a>00182 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00183"></a>00183 |
| <a name="l00184"></a>00184 <span class="comment">/* Read the input sample */</span> |
| <a name="l00185"></a>00185 x0 = *(ptr1++); |
| <a name="l00186"></a>00186 |
| <a name="l00187"></a>00187 <span class="comment">/* Perform the multiply-accumulate */</span> |
| <a name="l00188"></a>00188 sum0 += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) x0 *c0; |
| <a name="l00189"></a>00189 |
| <a name="l00190"></a>00190 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00191"></a>00191 tapCnt--; |
| <a name="l00192"></a>00192 } |
| <a name="l00193"></a>00193 |
| <a name="l00194"></a>00194 <span class="comment">/* The result is in the accumulator, store in the destination buffer. */</span> |
| <a name="l00195"></a>00195 *pDst++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (sum0 >> 31); |
| <a name="l00196"></a>00196 |
| <a name="l00197"></a>00197 <span class="comment">/* Increment the address modifier index of coefficient buffer */</span> |
| <a name="l00198"></a>00198 j++; |
| <a name="l00199"></a>00199 |
| <a name="l00200"></a>00200 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00201"></a>00201 i--; |
| <a name="l00202"></a>00202 } |
| <a name="l00203"></a>00203 |
| <a name="l00204"></a>00204 <span class="comment">/* Advance the state pointer by 1 </span> |
| <a name="l00205"></a>00205 <span class="comment"> * to process the next group of interpolation factor number samples */</span> |
| <a name="l00206"></a>00206 pState = pState + 1; |
| <a name="l00207"></a>00207 |
| <a name="l00208"></a>00208 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00209"></a>00209 blkCnt--; |
| <a name="l00210"></a>00210 } |
| <a name="l00211"></a>00211 |
| <a name="l00212"></a>00212 <span class="comment">/* Processing is complete. </span> |
| <a name="l00213"></a>00213 <span class="comment"> ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer. </span> |
| <a name="l00214"></a>00214 <span class="comment"> ** This prepares the state buffer for the next function call. */</span> |
| <a name="l00215"></a>00215 |
| <a name="l00216"></a>00216 <span class="comment">/* Points to the start of the state buffer */</span> |
| <a name="l00217"></a>00217 pStateCurnt = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a>; |
| <a name="l00218"></a>00218 |
| <a name="l00219"></a>00219 tapCnt = (phaseLen - 1u) >> 2u; |
| <a name="l00220"></a>00220 |
| <a name="l00221"></a>00221 <span class="comment">/* copy data */</span> |
| <a name="l00222"></a>00222 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00223"></a>00223 { |
| <a name="l00224"></a>00224 *pStateCurnt++ = *pState++; |
| <a name="l00225"></a>00225 *pStateCurnt++ = *pState++; |
| <a name="l00226"></a>00226 *pStateCurnt++ = *pState++; |
| <a name="l00227"></a>00227 *pStateCurnt++ = *pState++; |
| <a name="l00228"></a>00228 |
| <a name="l00229"></a>00229 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00230"></a>00230 tapCnt--; |
| <a name="l00231"></a>00231 } |
| <a name="l00232"></a>00232 |
| <a name="l00233"></a>00233 tapCnt = (phaseLen - 1u) % 0x04u; |
| <a name="l00234"></a>00234 |
| <a name="l00235"></a>00235 <span class="comment">/* copy data */</span> |
| <a name="l00236"></a>00236 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00237"></a>00237 { |
| <a name="l00238"></a>00238 *pStateCurnt++ = *pState++; |
| <a name="l00239"></a>00239 |
| <a name="l00240"></a>00240 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00241"></a>00241 tapCnt--; |
| <a name="l00242"></a>00242 } |
| <a name="l00243"></a>00243 |
| <a name="l00244"></a>00244 <span class="preprocessor">#else</span> |
| <a name="l00245"></a>00245 <span class="preprocessor"></span> |
| <a name="l00246"></a>00246 <span class="comment">/* Run the below code for Cortex-M0 */</span> |
| <a name="l00247"></a>00247 |
| <a name="l00248"></a>00248 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> sum; <span class="comment">/* Accumulator */</span> |
| <a name="l00249"></a>00249 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> x0, c0; <span class="comment">/* Temporary variables to hold state and coefficient values */</span> |
| <a name="l00250"></a>00250 uint32_t i, blkCnt; <span class="comment">/* Loop counters */</span> |
| <a name="l00251"></a>00251 uint16_t phaseLen = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5d243796584afc7cd6c557f00b7acca5">phaseLength</a>, tapCnt; <span class="comment">/* Length of each polyphase filter component */</span> |
| <a name="l00252"></a>00252 |
| <a name="l00253"></a>00253 |
| <a name="l00254"></a>00254 <span class="comment">/* S->pState buffer contains previous frame (phaseLen - 1) samples */</span> |
| <a name="l00255"></a>00255 <span class="comment">/* pStateCurnt points to the location where the new input data should be written */</span> |
| <a name="l00256"></a>00256 pStateCurnt = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a> + ((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) phaseLen - 1); |
| <a name="l00257"></a>00257 |
| <a name="l00258"></a>00258 <span class="comment">/* Total number of intput samples */</span> |
| <a name="l00259"></a>00259 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>; |
| <a name="l00260"></a>00260 |
| <a name="l00261"></a>00261 <span class="comment">/* Loop over the blockSize. */</span> |
| <a name="l00262"></a>00262 <span class="keywordflow">while</span>(blkCnt > 0u) |
| <a name="l00263"></a>00263 { |
| <a name="l00264"></a>00264 <span class="comment">/* Copy new input sample into the state buffer */</span> |
| <a name="l00265"></a>00265 *pStateCurnt++ = *pSrc++; |
| <a name="l00266"></a>00266 |
| <a name="l00267"></a>00267 <span class="comment">/* Loop over the Interpolation factor. */</span> |
| <a name="l00268"></a>00268 i = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00269"></a>00269 |
| <a name="l00270"></a>00270 <span class="keywordflow">while</span>(i > 0u) |
| <a name="l00271"></a>00271 { |
| <a name="l00272"></a>00272 <span class="comment">/* Set accumulator to zero */</span> |
| <a name="l00273"></a>00273 sum = 0; |
| <a name="l00274"></a>00274 |
| <a name="l00275"></a>00275 <span class="comment">/* Initialize state pointer */</span> |
| <a name="l00276"></a>00276 ptr1 = pState; |
| <a name="l00277"></a>00277 |
| <a name="l00278"></a>00278 <span class="comment">/* Initialize coefficient pointer */</span> |
| <a name="l00279"></a>00279 ptr2 = pCoeffs + (i - 1u); |
| <a name="l00280"></a>00280 |
| <a name="l00281"></a>00281 tapCnt = phaseLen; |
| <a name="l00282"></a>00282 |
| <a name="l00283"></a>00283 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00284"></a>00284 { |
| <a name="l00285"></a>00285 <span class="comment">/* Read the coefficient */</span> |
| <a name="l00286"></a>00286 c0 = *(ptr2); |
| <a name="l00287"></a>00287 |
| <a name="l00288"></a>00288 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span> |
| <a name="l00289"></a>00289 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>; |
| <a name="l00290"></a>00290 |
| <a name="l00291"></a>00291 <span class="comment">/* Read the input sample */</span> |
| <a name="l00292"></a>00292 x0 = *ptr1++; |
| <a name="l00293"></a>00293 |
| <a name="l00294"></a>00294 <span class="comment">/* Perform the multiply-accumulate */</span> |
| <a name="l00295"></a>00295 sum += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) x0 *c0; |
| <a name="l00296"></a>00296 |
| <a name="l00297"></a>00297 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00298"></a>00298 tapCnt--; |
| <a name="l00299"></a>00299 } |
| <a name="l00300"></a>00300 |
| <a name="l00301"></a>00301 <span class="comment">/* The result is in the accumulator, store in the destination buffer. */</span> |
| <a name="l00302"></a>00302 *pDst++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (sum >> 31); |
| <a name="l00303"></a>00303 |
| <a name="l00304"></a>00304 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00305"></a>00305 i--; |
| <a name="l00306"></a>00306 } |
| <a name="l00307"></a>00307 |
| <a name="l00308"></a>00308 <span class="comment">/* Advance the state pointer by 1 </span> |
| <a name="l00309"></a>00309 <span class="comment"> * to process the next group of interpolation factor number samples */</span> |
| <a name="l00310"></a>00310 pState = pState + 1; |
| <a name="l00311"></a>00311 |
| <a name="l00312"></a>00312 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00313"></a>00313 blkCnt--; |
| <a name="l00314"></a>00314 } |
| <a name="l00315"></a>00315 |
| <a name="l00316"></a>00316 <span class="comment">/* Processing is complete. </span> |
| <a name="l00317"></a>00317 <span class="comment"> ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer. </span> |
| <a name="l00318"></a>00318 <span class="comment"> ** This prepares the state buffer for the next function call. */</span> |
| <a name="l00319"></a>00319 |
| <a name="l00320"></a>00320 <span class="comment">/* Points to the start of the state buffer */</span> |
| <a name="l00321"></a>00321 pStateCurnt = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a>; |
| <a name="l00322"></a>00322 |
| <a name="l00323"></a>00323 tapCnt = phaseLen - 1u; |
| <a name="l00324"></a>00324 |
| <a name="l00325"></a>00325 <span class="comment">/* copy data */</span> |
| <a name="l00326"></a>00326 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00327"></a>00327 { |
| <a name="l00328"></a>00328 *pStateCurnt++ = *pState++; |
| <a name="l00329"></a>00329 |
| <a name="l00330"></a>00330 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00331"></a>00331 tapCnt--; |
| <a name="l00332"></a>00332 } |
| <a name="l00333"></a>00333 |
| <a name="l00334"></a>00334 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span> |
| <a name="l00335"></a>00335 |
| <a name="l00336"></a>00336 } |
| <a name="l00337"></a>00337 |
| </pre></div></div> |
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