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| <h1>arm_iir_lattice_f32.c</h1> </div> |
| </div> |
| <div class="contents"> |
| <a href="arm__iir__lattice__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> |
| <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_iir_lattice_f32.c </span> |
| <a name="l00009"></a>00009 <span class="comment">* </span> |
| <a name="l00010"></a>00010 <span class="comment">* Description: Floating-point IIR Lattice filter processing function. </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="l00120"></a><a class="code" href="group___i_i_r___lattice.html#ga56164a0fe48619b8ceec160347bdd2ff">00120</a> <span class="keywordtype">void</span> <a class="code" href="group___i_i_r___lattice.html#ga56164a0fe48619b8ceec160347bdd2ff" title="Processing function for the floating-point IIR lattice filter.">arm_iir_lattice_f32</a>( |
| <a name="l00121"></a>00121 <span class="keyword">const</span> <a class="code" href="structarm__iir__lattice__instance__f32.html" title="Instance structure for the floating-point IIR lattice filter.">arm_iir_lattice_instance_f32</a> * S, |
| <a name="l00122"></a>00122 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> * pSrc, |
| <a name="l00123"></a>00123 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> * pDst, |
| <a name="l00124"></a>00124 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>) |
| <a name="l00125"></a>00125 { |
| <a name="l00126"></a>00126 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> fcurr, fnext = 0, gcurr, gnext; <span class="comment">/* Temporary variables for lattice stages */</span> |
| <a name="l00127"></a>00127 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> acc; <span class="comment">/* Accumlator */</span> |
| <a name="l00128"></a>00128 uint32_t blkCnt, tapCnt; <span class="comment">/* temporary variables for counts */</span> |
| <a name="l00129"></a>00129 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> *px1, *px2, *pk, *pv; <span class="comment">/* temporary pointers for state and coef */</span> |
| <a name="l00130"></a>00130 uint32_t numStages = S-><a class="code" href="structarm__iir__lattice__instance__f32.html#af8de449af5efe1f30be82f9ba35587ee">numStages</a>; <span class="comment">/* number of stages */</span> |
| <a name="l00131"></a>00131 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> *pState; <span class="comment">/* State pointer */</span> |
| <a name="l00132"></a>00132 <a class="code" href="arm__math_8h.html#a4611b605e45ab401f02cab15c5e38715" title="32-bit floating-point type definition.">float32_t</a> *pStateCurnt; <span class="comment">/* State current pointer */</span> |
| <a name="l00133"></a>00133 |
| <a name="l00134"></a>00134 |
| <a name="l00135"></a>00135 <span class="preprocessor">#ifndef ARM_MATH_CM0</span> |
| <a name="l00136"></a>00136 <span class="preprocessor"></span> |
| <a name="l00137"></a>00137 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span> |
| <a name="l00138"></a>00138 |
| <a name="l00139"></a>00139 gcurr = 0.0f; |
| <a name="l00140"></a>00140 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>; |
| <a name="l00141"></a>00141 |
| <a name="l00142"></a>00142 pState = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#a30babe7815510219e6e3d28e6e4a5969">pState</a>[0]; |
| <a name="l00143"></a>00143 |
| <a name="l00144"></a>00144 <span class="comment">/* Sample processing */</span> |
| <a name="l00145"></a>00145 <span class="keywordflow">while</span>(blkCnt > 0u) |
| <a name="l00146"></a>00146 { |
| <a name="l00147"></a>00147 <span class="comment">/* Read Sample from input buffer */</span> |
| <a name="l00148"></a>00148 <span class="comment">/* fN(n) = x(n) */</span> |
| <a name="l00149"></a>00149 fcurr = *pSrc++; |
| <a name="l00150"></a>00150 |
| <a name="l00151"></a>00151 <span class="comment">/* Initialize state read pointer */</span> |
| <a name="l00152"></a>00152 px1 = pState; |
| <a name="l00153"></a>00153 <span class="comment">/* Initialize state write pointer */</span> |
| <a name="l00154"></a>00154 px2 = pState; |
| <a name="l00155"></a>00155 <span class="comment">/* Set accumulator to zero */</span> |
| <a name="l00156"></a>00156 acc = 0.0f; |
| <a name="l00157"></a>00157 <span class="comment">/* Initialize Ladder coeff pointer */</span> |
| <a name="l00158"></a>00158 pv = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#afc7c8f577e6f27d097fe55f57e707f72">pvCoeffs</a>[0]; |
| <a name="l00159"></a>00159 <span class="comment">/* Initialize Reflection coeff pointer */</span> |
| <a name="l00160"></a>00160 pk = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#aa69fcdd3775e828d450ce1bbd978fa31">pkCoeffs</a>[0]; |
| <a name="l00161"></a>00161 |
| <a name="l00162"></a>00162 |
| <a name="l00163"></a>00163 <span class="comment">/* Process sample for first tap */</span> |
| <a name="l00164"></a>00164 gcurr = *px1++; |
| <a name="l00165"></a>00165 <span class="comment">/* fN-1(n) = fN(n) - kN * gN-1(n-1) */</span> |
| <a name="l00166"></a>00166 fnext = fcurr - ((*pk) * gcurr); |
| <a name="l00167"></a>00167 <span class="comment">/* gN(n) = kN * fN-1(n) + gN-1(n-1) */</span> |
| <a name="l00168"></a>00168 gnext = (fnext * (*pk++)) + gcurr; |
| <a name="l00169"></a>00169 <span class="comment">/* write gN(n) into state for next sample processing */</span> |
| <a name="l00170"></a>00170 *px2++ = gnext; |
| <a name="l00171"></a>00171 <span class="comment">/* y(n) += gN(n) * vN */</span> |
| <a name="l00172"></a>00172 acc += (gnext * (*pv++)); |
| <a name="l00173"></a>00173 |
| <a name="l00174"></a>00174 <span class="comment">/* Update f values for next coefficient processing */</span> |
| <a name="l00175"></a>00175 fcurr = fnext; |
| <a name="l00176"></a>00176 |
| <a name="l00177"></a>00177 <span class="comment">/* Loop unrolling. Process 4 taps at a time. */</span> |
| <a name="l00178"></a>00178 tapCnt = (numStages - 1u) >> 2; |
| <a name="l00179"></a>00179 |
| <a name="l00180"></a>00180 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00181"></a>00181 { |
| <a name="l00182"></a>00182 <span class="comment">/* Process sample for 2nd, 6th ...taps */</span> |
| <a name="l00183"></a>00183 <span class="comment">/* Read gN-2(n-1) from state buffer */</span> |
| <a name="l00184"></a>00184 gcurr = *px1++; |
| <a name="l00185"></a>00185 <span class="comment">/* Process sample for 2nd, 6th .. taps */</span> |
| <a name="l00186"></a>00186 <span class="comment">/* fN-2(n) = fN-1(n) - kN-1 * gN-2(n-1) */</span> |
| <a name="l00187"></a>00187 fnext = fcurr - ((*pk) * gcurr); |
| <a name="l00188"></a>00188 <span class="comment">/* gN-1(n) = kN-1 * fN-2(n) + gN-2(n-1) */</span> |
| <a name="l00189"></a>00189 gnext = (fnext * (*pk++)) + gcurr; |
| <a name="l00190"></a>00190 <span class="comment">/* y(n) += gN-1(n) * vN-1 */</span> |
| <a name="l00191"></a>00191 <span class="comment">/* process for gN-5(n) * vN-5, gN-9(n) * vN-9 ... */</span> |
| <a name="l00192"></a>00192 acc += (gnext * (*pv++)); |
| <a name="l00193"></a>00193 <span class="comment">/* write gN-1(n) into state for next sample processing */</span> |
| <a name="l00194"></a>00194 *px2++ = gnext; |
| <a name="l00195"></a>00195 |
| <a name="l00196"></a>00196 |
| <a name="l00197"></a>00197 <span class="comment">/* Process sample for 3nd, 7th ...taps */</span> |
| <a name="l00198"></a>00198 <span class="comment">/* Read gN-3(n-1) from state buffer */</span> |
| <a name="l00199"></a>00199 gcurr = *px1++; |
| <a name="l00200"></a>00200 <span class="comment">/* Process sample for 3rd, 7th .. taps */</span> |
| <a name="l00201"></a>00201 <span class="comment">/* fN-3(n) = fN-2(n) - kN-2 * gN-3(n-1) */</span> |
| <a name="l00202"></a>00202 fcurr = fnext - ((*pk) * gcurr); |
| <a name="l00203"></a>00203 <span class="comment">/* gN-2(n) = kN-2 * fN-3(n) + gN-3(n-1) */</span> |
| <a name="l00204"></a>00204 gnext = (fcurr * (*pk++)) + gcurr; |
| <a name="l00205"></a>00205 <span class="comment">/* y(n) += gN-2(n) * vN-2 */</span> |
| <a name="l00206"></a>00206 <span class="comment">/* process for gN-6(n) * vN-6, gN-10(n) * vN-10 ... */</span> |
| <a name="l00207"></a>00207 acc += (gnext * (*pv++)); |
| <a name="l00208"></a>00208 <span class="comment">/* write gN-2(n) into state for next sample processing */</span> |
| <a name="l00209"></a>00209 *px2++ = gnext; |
| <a name="l00210"></a>00210 |
| <a name="l00211"></a>00211 |
| <a name="l00212"></a>00212 <span class="comment">/* Process sample for 4th, 8th ...taps */</span> |
| <a name="l00213"></a>00213 <span class="comment">/* Read gN-4(n-1) from state buffer */</span> |
| <a name="l00214"></a>00214 gcurr = *px1++; |
| <a name="l00215"></a>00215 <span class="comment">/* Process sample for 4th, 8th .. taps */</span> |
| <a name="l00216"></a>00216 <span class="comment">/* fN-4(n) = fN-3(n) - kN-3 * gN-4(n-1) */</span> |
| <a name="l00217"></a>00217 fnext = fcurr - ((*pk) * gcurr); |
| <a name="l00218"></a>00218 <span class="comment">/* gN-3(n) = kN-3 * fN-4(n) + gN-4(n-1) */</span> |
| <a name="l00219"></a>00219 gnext = (fnext * (*pk++)) + gcurr; |
| <a name="l00220"></a>00220 <span class="comment">/* y(n) += gN-3(n) * vN-3 */</span> |
| <a name="l00221"></a>00221 <span class="comment">/* process for gN-7(n) * vN-7, gN-11(n) * vN-11 ... */</span> |
| <a name="l00222"></a>00222 acc += (gnext * (*pv++)); |
| <a name="l00223"></a>00223 <span class="comment">/* write gN-3(n) into state for next sample processing */</span> |
| <a name="l00224"></a>00224 *px2++ = gnext; |
| <a name="l00225"></a>00225 |
| <a name="l00226"></a>00226 |
| <a name="l00227"></a>00227 <span class="comment">/* Process sample for 5th, 9th ...taps */</span> |
| <a name="l00228"></a>00228 <span class="comment">/* Read gN-5(n-1) from state buffer */</span> |
| <a name="l00229"></a>00229 gcurr = *px1++; |
| <a name="l00230"></a>00230 <span class="comment">/* Process sample for 5th, 9th .. taps */</span> |
| <a name="l00231"></a>00231 <span class="comment">/* fN-5(n) = fN-4(n) - kN-4 * gN-1(n-1) */</span> |
| <a name="l00232"></a>00232 fcurr = fnext - ((*pk) * gcurr); |
| <a name="l00233"></a>00233 <span class="comment">/* gN-4(n) = kN-4 * fN-5(n) + gN-5(n-1) */</span> |
| <a name="l00234"></a>00234 gnext = (fcurr * (*pk++)) + gcurr; |
| <a name="l00235"></a>00235 <span class="comment">/* y(n) += gN-4(n) * vN-4 */</span> |
| <a name="l00236"></a>00236 <span class="comment">/* process for gN-8(n) * vN-8, gN-12(n) * vN-12 ... */</span> |
| <a name="l00237"></a>00237 acc += (gnext * (*pv++)); |
| <a name="l00238"></a>00238 <span class="comment">/* write gN-4(n) into state for next sample processing */</span> |
| <a name="l00239"></a>00239 *px2++ = gnext; |
| <a name="l00240"></a>00240 |
| <a name="l00241"></a>00241 tapCnt--; |
| <a name="l00242"></a>00242 |
| <a name="l00243"></a>00243 } |
| <a name="l00244"></a>00244 |
| <a name="l00245"></a>00245 fnext = fcurr; |
| <a name="l00246"></a>00246 |
| <a name="l00247"></a>00247 <span class="comment">/* If the filter length is not a multiple of 4, compute the remaining filter taps */</span> |
| <a name="l00248"></a>00248 tapCnt = (numStages - 1u) % 0x4u; |
| <a name="l00249"></a>00249 |
| <a name="l00250"></a>00250 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00251"></a>00251 { |
| <a name="l00252"></a>00252 gcurr = *px1++; |
| <a name="l00253"></a>00253 <span class="comment">/* Process sample for last taps */</span> |
| <a name="l00254"></a>00254 fnext = fcurr - ((*pk) * gcurr); |
| <a name="l00255"></a>00255 gnext = (fnext * (*pk++)) + gcurr; |
| <a name="l00256"></a>00256 <span class="comment">/* Output samples for last taps */</span> |
| <a name="l00257"></a>00257 acc += (gnext * (*pv++)); |
| <a name="l00258"></a>00258 *px2++ = gnext; |
| <a name="l00259"></a>00259 fcurr = fnext; |
| <a name="l00260"></a>00260 |
| <a name="l00261"></a>00261 tapCnt--; |
| <a name="l00262"></a>00262 |
| <a name="l00263"></a>00263 } |
| <a name="l00264"></a>00264 |
| <a name="l00265"></a>00265 |
| <a name="l00266"></a>00266 <span class="comment">/* y(n) += g0(n) * v0 */</span> |
| <a name="l00267"></a>00267 acc += (fnext * (*pv)); |
| <a name="l00268"></a>00268 |
| <a name="l00269"></a>00269 *px2++ = fnext; |
| <a name="l00270"></a>00270 |
| <a name="l00271"></a>00271 <span class="comment">/* write out into pDst */</span> |
| <a name="l00272"></a>00272 *pDst++ = acc; |
| <a name="l00273"></a>00273 |
| <a name="l00274"></a>00274 <span class="comment">/* Advance the state pointer by 4 to process the next group of 4 samples */</span> |
| <a name="l00275"></a>00275 pState = pState + 1u; |
| <a name="l00276"></a>00276 blkCnt--; |
| <a name="l00277"></a>00277 |
| <a name="l00278"></a>00278 } |
| <a name="l00279"></a>00279 |
| <a name="l00280"></a>00280 <span class="comment">/* Processing is complete. Now copy last S->numStages samples to start of the buffer </span> |
| <a name="l00281"></a>00281 <span class="comment"> for the preperation of next frame process */</span> |
| <a name="l00282"></a>00282 |
| <a name="l00283"></a>00283 <span class="comment">/* Points to the start of the state buffer */</span> |
| <a name="l00284"></a>00284 pStateCurnt = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#a30babe7815510219e6e3d28e6e4a5969">pState</a>[0]; |
| <a name="l00285"></a>00285 pState = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#a30babe7815510219e6e3d28e6e4a5969">pState</a>[<a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>]; |
| <a name="l00286"></a>00286 |
| <a name="l00287"></a>00287 tapCnt = numStages >> 2u; |
| <a name="l00288"></a>00288 |
| <a name="l00289"></a>00289 <span class="comment">/* copy data */</span> |
| <a name="l00290"></a>00290 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00291"></a>00291 { |
| <a name="l00292"></a>00292 *pStateCurnt++ = *pState++; |
| <a name="l00293"></a>00293 *pStateCurnt++ = *pState++; |
| <a name="l00294"></a>00294 *pStateCurnt++ = *pState++; |
| <a name="l00295"></a>00295 *pStateCurnt++ = *pState++; |
| <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 |
| <a name="l00302"></a>00302 <span class="comment">/* Calculate remaining number of copies */</span> |
| <a name="l00303"></a>00303 tapCnt = (numStages) % 0x4u; |
| <a name="l00304"></a>00304 |
| <a name="l00305"></a>00305 <span class="comment">/* Copy the remaining q31_t data */</span> |
| <a name="l00306"></a>00306 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00307"></a>00307 { |
| <a name="l00308"></a>00308 *pStateCurnt++ = *pState++; |
| <a name="l00309"></a>00309 |
| <a name="l00310"></a>00310 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00311"></a>00311 tapCnt--; |
| <a name="l00312"></a>00312 } |
| <a name="l00313"></a>00313 |
| <a name="l00314"></a>00314 <span class="preprocessor">#else</span> |
| <a name="l00315"></a>00315 <span class="preprocessor"></span> |
| <a name="l00316"></a>00316 <span class="comment">/* Run the below code for Cortex-M0 */</span> |
| <a name="l00317"></a>00317 |
| <a name="l00318"></a>00318 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>; |
| <a name="l00319"></a>00319 |
| <a name="l00320"></a>00320 pState = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#a30babe7815510219e6e3d28e6e4a5969">pState</a>[0]; |
| <a name="l00321"></a>00321 |
| <a name="l00322"></a>00322 <span class="comment">/* Sample processing */</span> |
| <a name="l00323"></a>00323 <span class="keywordflow">while</span>(blkCnt > 0u) |
| <a name="l00324"></a>00324 { |
| <a name="l00325"></a>00325 <span class="comment">/* Read Sample from input buffer */</span> |
| <a name="l00326"></a>00326 <span class="comment">/* fN(n) = x(n) */</span> |
| <a name="l00327"></a>00327 fcurr = *pSrc++; |
| <a name="l00328"></a>00328 |
| <a name="l00329"></a>00329 <span class="comment">/* Initialize state read pointer */</span> |
| <a name="l00330"></a>00330 px1 = pState; |
| <a name="l00331"></a>00331 <span class="comment">/* Initialize state write pointer */</span> |
| <a name="l00332"></a>00332 px2 = pState; |
| <a name="l00333"></a>00333 <span class="comment">/* Set accumulator to zero */</span> |
| <a name="l00334"></a>00334 acc = 0.0f; |
| <a name="l00335"></a>00335 <span class="comment">/* Initialize Ladder coeff pointer */</span> |
| <a name="l00336"></a>00336 pv = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#afc7c8f577e6f27d097fe55f57e707f72">pvCoeffs</a>[0]; |
| <a name="l00337"></a>00337 <span class="comment">/* Initialize Reflection coeff pointer */</span> |
| <a name="l00338"></a>00338 pk = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#aa69fcdd3775e828d450ce1bbd978fa31">pkCoeffs</a>[0]; |
| <a name="l00339"></a>00339 |
| <a name="l00340"></a>00340 |
| <a name="l00341"></a>00341 <span class="comment">/* Process sample for numStages */</span> |
| <a name="l00342"></a>00342 tapCnt = numStages; |
| <a name="l00343"></a>00343 |
| <a name="l00344"></a>00344 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00345"></a>00345 { |
| <a name="l00346"></a>00346 gcurr = *px1++; |
| <a name="l00347"></a>00347 <span class="comment">/* Process sample for last taps */</span> |
| <a name="l00348"></a>00348 fnext = fcurr - ((*pk) * gcurr); |
| <a name="l00349"></a>00349 gnext = (fnext * (*pk++)) + gcurr; |
| <a name="l00350"></a>00350 |
| <a name="l00351"></a>00351 <span class="comment">/* Output samples for last taps */</span> |
| <a name="l00352"></a>00352 acc += (gnext * (*pv++)); |
| <a name="l00353"></a>00353 *px2++ = gnext; |
| <a name="l00354"></a>00354 fcurr = fnext; |
| <a name="l00355"></a>00355 |
| <a name="l00356"></a>00356 <span class="comment">/* Decrementing loop counter */</span> |
| <a name="l00357"></a>00357 tapCnt--; |
| <a name="l00358"></a>00358 |
| <a name="l00359"></a>00359 } |
| <a name="l00360"></a>00360 |
| <a name="l00361"></a>00361 <span class="comment">/* y(n) += g0(n) * v0 */</span> |
| <a name="l00362"></a>00362 acc += (fnext * (*pv)); |
| <a name="l00363"></a>00363 |
| <a name="l00364"></a>00364 *px2++ = fnext; |
| <a name="l00365"></a>00365 |
| <a name="l00366"></a>00366 <span class="comment">/* write out into pDst */</span> |
| <a name="l00367"></a>00367 *pDst++ = acc; |
| <a name="l00368"></a>00368 |
| <a name="l00369"></a>00369 <span class="comment">/* Advance the state pointer by 1 to process the next group of samples */</span> |
| <a name="l00370"></a>00370 pState = pState + 1u; |
| <a name="l00371"></a>00371 blkCnt--; |
| <a name="l00372"></a>00372 |
| <a name="l00373"></a>00373 } |
| <a name="l00374"></a>00374 |
| <a name="l00375"></a>00375 <span class="comment">/* Processing is complete. Now copy last S->numStages samples to start of the buffer </span> |
| <a name="l00376"></a>00376 <span class="comment"> for the preperation of next frame process */</span> |
| <a name="l00377"></a>00377 |
| <a name="l00378"></a>00378 <span class="comment">/* Points to the start of the state buffer */</span> |
| <a name="l00379"></a>00379 pStateCurnt = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#a30babe7815510219e6e3d28e6e4a5969">pState</a>[0]; |
| <a name="l00380"></a>00380 pState = &S-><a class="code" href="structarm__iir__lattice__instance__f32.html#a30babe7815510219e6e3d28e6e4a5969">pState</a>[<a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>]; |
| <a name="l00381"></a>00381 |
| <a name="l00382"></a>00382 tapCnt = numStages; |
| <a name="l00383"></a>00383 |
| <a name="l00384"></a>00384 <span class="comment">/* Copy the data */</span> |
| <a name="l00385"></a>00385 <span class="keywordflow">while</span>(tapCnt > 0u) |
| <a name="l00386"></a>00386 { |
| <a name="l00387"></a>00387 *pStateCurnt++ = *pState++; |
| <a name="l00388"></a>00388 |
| <a name="l00389"></a>00389 <span class="comment">/* Decrement the loop counter */</span> |
| <a name="l00390"></a>00390 tapCnt--; |
| <a name="l00391"></a>00391 } |
| <a name="l00392"></a>00392 |
| <a name="l00393"></a>00393 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span> |
| <a name="l00394"></a>00394 |
| <a name="l00395"></a>00395 } |
| <a name="l00396"></a>00396 |
| <a name="l00397"></a>00397 |
| <a name="l00398"></a>00398 |
| <a name="l00399"></a>00399 |
| </pre></div></div> |
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