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| <h1>arm_biquad_cascade_df1_32x64_q31.c</h1> </div> |
| </div> |
| <div class="contents"> |
| <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> |
| <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_biquad_cascade_df1_32x64_q31.c </span> |
| <a name="l00009"></a>00009 <span class="comment">* </span> |
| <a name="l00010"></a>00010 <span class="comment">* Description: High precision Q31 Biquad cascade 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="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>( |
| <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, |
| <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, |
| <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, |
| <a name="l00180"></a>00180 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>) |
| <a name="l00181"></a>00181 { |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <a name="l00192"></a>00192 |
| <a name="l00193"></a>00193 |
| <a name="l00194"></a>00194 #ifndef ARM_MATH_CM0 |
| <a name="l00195"></a>00195 |
| <a name="l00196"></a>00196 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span> |
| <a name="l00197"></a>00197 |
| <a name="l00198"></a>00198 <span class="keywordflow">do</span> |
| <a name="l00199"></a>00199 { |
| <a name="l00200"></a>00200 <span class="comment">/* Reading the coefficients */</span> |
| <a name="l00201"></a>00201 b0 = *pCoeffs++; |
| <a name="l00202"></a>00202 b1 = *pCoeffs++; |
| <a name="l00203"></a>00203 b2 = *pCoeffs++; |
| <a name="l00204"></a>00204 a1 = *pCoeffs++; |
| <a name="l00205"></a>00205 a2 = *pCoeffs++; |
| <a name="l00206"></a>00206 |
| <a name="l00207"></a>00207 <span class="comment">/* Reading the state values */</span> |
| <a name="l00208"></a>00208 Xn1 = pState[0]; |
| <a name="l00209"></a>00209 Xn2 = pState[1]; |
| <a name="l00210"></a>00210 Yn1 = pState[2]; |
| <a name="l00211"></a>00211 Yn2 = pState[3]; |
| <a name="l00212"></a>00212 |
| <a name="l00213"></a>00213 <span class="comment">/* Apply loop unrolling and compute 4 output values simultaneously. */</span> |
| <a name="l00214"></a>00214 <span class="comment">/* The variable acc hold output value that is being computed and </span> |
| <a name="l00215"></a>00215 <span class="comment"> * stored in the destination buffer </span> |
| <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> |
| <a name="l00217"></a>00217 <span class="comment"> */</span> |
| <a name="l00218"></a>00218 |
| <a name="l00219"></a>00219 sample = blockSize >> 2u; |
| <a name="l00220"></a>00220 |
| <a name="l00221"></a>00221 <span class="comment">/* First part of the processing with loop unrolling. Compute 4 outputs at a time. </span> |
| <a name="l00222"></a>00222 <span class="comment"> ** a second loop below computes the remaining 1 to 3 samples. */</span> |
| <a name="l00223"></a>00223 <span class="keywordflow">while</span>(sample > 0u) |
| <a name="l00224"></a>00224 { |
| <a name="l00225"></a>00225 <span class="comment">/* Read the input */</span> |
| <a name="l00226"></a>00226 Xn = *pIn++; |
| <a name="l00227"></a>00227 |
| <a name="l00228"></a>00228 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span> |
| <a name="l00229"></a>00229 Xn = Xn << 32; |
| <a name="l00230"></a>00230 |
| <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> |
| <a name="l00232"></a>00232 |
| <a name="l00233"></a>00233 <span class="comment">/* acc = b0 * x[n] */</span> |
| <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); |
| <a name="l00235"></a>00235 <span class="comment">/* acc += b1 * x[n-1] */</span> |
| <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); |
| <a name="l00237"></a>00237 <span class="comment">/* acc += b[2] * x[n-2] */</span> |
| <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); |
| <a name="l00239"></a>00239 <span class="comment">/* acc += a1 * y[n-1] */</span> |
| <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); |
| <a name="l00241"></a>00241 <span class="comment">/* acc += a2 * y[n-2] */</span> |
| <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); |
| <a name="l00243"></a>00243 |
| <a name="l00244"></a>00244 <span class="comment">/* The result is converted to 1.63 , Yn2 variable is reused */</span> |
| <a name="l00245"></a>00245 Yn2 = acc << shift; |
| <a name="l00246"></a>00246 |
| <a name="l00247"></a>00247 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span> |
| <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)); |
| <a name="l00249"></a>00249 |
| <a name="l00250"></a>00250 <span class="comment">/* Read the second input into Xn2, to reuse the value */</span> |
| <a name="l00251"></a>00251 Xn2 = *pIn++; |
| <a name="l00252"></a>00252 |
| <a name="l00253"></a>00253 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span> |
| <a name="l00254"></a>00254 Xn2 = Xn2 << 32; |
| <a name="l00255"></a>00255 |
| <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> |
| <a name="l00257"></a>00257 |
| <a name="l00258"></a>00258 <span class="comment">/* acc = b0 * x[n] */</span> |
| <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); |
| <a name="l00260"></a>00260 <span class="comment">/* acc += b1 * x[n-1] */</span> |
| <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); |
| <a name="l00262"></a>00262 <span class="comment">/* acc += b[2] * x[n-2] */</span> |
| <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); |
| <a name="l00264"></a>00264 <span class="comment">/* acc += a1 * y[n-1] */</span> |
| <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); |
| <a name="l00266"></a>00266 <span class="comment">/* acc += a2 * y[n-2] */</span> |
| <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); |
| <a name="l00268"></a>00268 |
| <a name="l00269"></a>00269 <span class="comment">/* The result is converted to 1.63, Yn1 variable is reused */</span> |
| <a name="l00270"></a>00270 Yn1 = acc << shift; |
| <a name="l00271"></a>00271 |
| <a name="l00272"></a>00272 <span class="comment">/* The result is converted to 1.31 */</span> |
| <a name="l00273"></a>00273 <span class="comment">/* Store the output in the destination buffer. */</span> |
| <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)); |
| <a name="l00275"></a>00275 |
| <a name="l00276"></a>00276 <span class="comment">/* Read the third input into Xn1, to reuse the value */</span> |
| <a name="l00277"></a>00277 Xn1 = *pIn++; |
| <a name="l00278"></a>00278 |
| <a name="l00279"></a>00279 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span> |
| <a name="l00280"></a>00280 Xn1 = Xn1 << 32; |
| <a name="l00281"></a>00281 |
| <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> |
| <a name="l00283"></a>00283 <span class="comment">/* acc = b0 * x[n] */</span> |
| <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); |
| <a name="l00285"></a>00285 <span class="comment">/* acc += b1 * x[n-1] */</span> |
| <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); |
| <a name="l00287"></a>00287 <span class="comment">/* acc += b[2] * x[n-2] */</span> |
| <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); |
| <a name="l00289"></a>00289 <span class="comment">/* acc += a1 * y[n-1] */</span> |
| <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); |
| <a name="l00291"></a>00291 <span class="comment">/* acc += a2 * y[n-2] */</span> |
| <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); |
| <a name="l00293"></a>00293 |
| <a name="l00294"></a>00294 <span class="comment">/* The result is converted to 1.63, Yn2 variable is reused */</span> |
| <a name="l00295"></a>00295 Yn2 = acc << shift; |
| <a name="l00296"></a>00296 |
| <a name="l00297"></a>00297 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span> |
| <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)); |
| <a name="l00299"></a>00299 |
| <a name="l00300"></a>00300 <span class="comment">/* Read the fourth input into Xn, to reuse the value */</span> |
| <a name="l00301"></a>00301 Xn = *pIn++; |
| <a name="l00302"></a>00302 |
| <a name="l00303"></a>00303 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span> |
| <a name="l00304"></a>00304 Xn = Xn << 32; |
| <a name="l00305"></a>00305 |
| <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> |
| <a name="l00307"></a>00307 <span class="comment">/* acc = b0 * x[n] */</span> |
| <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); |
| <a name="l00309"></a>00309 <span class="comment">/* acc += b1 * x[n-1] */</span> |
| <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); |
| <a name="l00311"></a>00311 <span class="comment">/* acc += b[2] * x[n-2] */</span> |
| <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); |
| <a name="l00313"></a>00313 <span class="comment">/* acc += a1 * y[n-1] */</span> |
| <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); |
| <a name="l00315"></a>00315 <span class="comment">/* acc += a2 * y[n-2] */</span> |
| <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); |
| <a name="l00317"></a>00317 |
| <a name="l00318"></a>00318 <span class="comment">/* The result is converted to 1.63, Yn1 variable is reused */</span> |
| <a name="l00319"></a>00319 Yn1 = acc << shift; |
| <a name="l00320"></a>00320 |
| <a name="l00321"></a>00321 <span class="comment">/* Every time after the output is computed state should be updated. */</span> |
| <a name="l00322"></a>00322 <span class="comment">/* The states should be updated as: */</span> |
| <a name="l00323"></a>00323 <span class="comment">/* Xn2 = Xn1 */</span> |
| <a name="l00324"></a>00324 <span class="comment">/* Xn1 = Xn */</span> |
| <a name="l00325"></a>00325 <span class="comment">/* Yn2 = Yn1 */</span> |
| <a name="l00326"></a>00326 <span class="comment">/* Yn1 = acc */</span> |
| <a name="l00327"></a>00327 Xn2 = Xn1; |
| <a name="l00328"></a>00328 Xn1 = Xn; |
| <a name="l00329"></a>00329 |
| <a name="l00330"></a>00330 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span> |
| <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)); |
| <a name="l00332"></a>00332 |
| <a name="l00333"></a>00333 <span class="comment">/* decrement the loop counter */</span> |
| <a name="l00334"></a>00334 sample--; |
| <a name="l00335"></a>00335 } |
| <a name="l00336"></a>00336 |
| <a name="l00337"></a>00337 <span class="comment">/* If the blockSize is not a multiple of 4, compute any remaining output samples here. </span> |
| <a name="l00338"></a>00338 <span class="comment"> ** No loop unrolling is used. */</span> |
| <a name="l00339"></a>00339 sample = (blockSize & 0x3u); |
| <a name="l00340"></a>00340 |
| <a name="l00341"></a>00341 <span class="keywordflow">while</span>(sample > 0u) |
| <a name="l00342"></a>00342 { |
| <a name="l00343"></a>00343 <span class="comment">/* Read the input */</span> |
| <a name="l00344"></a>00344 Xn = *pIn++; |
| <a name="l00345"></a>00345 |
| <a name="l00346"></a>00346 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span> |
| <a name="l00347"></a>00347 Xn = Xn << 32; |
| <a name="l00348"></a>00348 |
| <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> |
| <a name="l00350"></a>00350 <span class="comment">/* acc = b0 * x[n] */</span> |
| <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); |
| <a name="l00352"></a>00352 <span class="comment">/* acc += b1 * x[n-1] */</span> |
| <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); |
| <a name="l00354"></a>00354 <span class="comment">/* acc += b[2] * x[n-2] */</span> |
| <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); |
| <a name="l00356"></a>00356 <span class="comment">/* acc += a1 * y[n-1] */</span> |
| <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); |
| <a name="l00358"></a>00358 <span class="comment">/* acc += a2 * y[n-2] */</span> |
| <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); |
| <a name="l00360"></a>00360 |
| <a name="l00361"></a>00361 <span class="comment">/* Every time after the output is computed state should be updated. */</span> |
| <a name="l00362"></a>00362 <span class="comment">/* The states should be updated as: */</span> |
| <a name="l00363"></a>00363 <span class="comment">/* Xn2 = Xn1 */</span> |
| <a name="l00364"></a>00364 <span class="comment">/* Xn1 = Xn */</span> |
| <a name="l00365"></a>00365 <span class="comment">/* Yn2 = Yn1 */</span> |
| <a name="l00366"></a>00366 <span class="comment">/* Yn1 = acc */</span> |
| <a name="l00367"></a>00367 Xn2 = Xn1; |
| <a name="l00368"></a>00368 Xn1 = Xn; |
| <a name="l00369"></a>00369 Yn2 = Yn1; |
| <a name="l00370"></a>00370 Yn1 = acc << shift; |
| <a name="l00371"></a>00371 |
| <a name="l00372"></a>00372 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span> |
| <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)); |
| <a name="l00374"></a>00374 |
| <a name="l00375"></a>00375 <span class="comment">/* decrement the loop counter */</span> |
| <a name="l00376"></a>00376 sample--; |
| <a name="l00377"></a>00377 } |
| <a name="l00378"></a>00378 |
| <a name="l00379"></a>00379 <span class="comment">/* The first stage output is given as input to the second stage. */</span> |
| <a name="l00380"></a>00380 pIn = pDst; |
| <a name="l00381"></a>00381 |
| <a name="l00382"></a>00382 <span class="comment">/* Reset to destination buffer working pointer */</span> |
| <a name="l00383"></a>00383 pOut = pDst; |
| <a name="l00384"></a>00384 |
| <a name="l00385"></a>00385 <span class="comment">/* Store the updated state variables back into the pState array */</span> |
| <a name="l00386"></a>00386 *pState++ = Xn1; |
| <a name="l00387"></a>00387 *pState++ = Xn2; |
| <a name="l00388"></a>00388 *pState++ = Yn1; |
| <a name="l00389"></a>00389 *pState++ = Yn2; |
| <a name="l00390"></a>00390 |
| <a name="l00391"></a>00391 } <span class="keywordflow">while</span>(--stage); |
| <a name="l00392"></a>00392 |
| <a name="l00393"></a>00393 <span class="preprocessor">#else</span> |
| <a name="l00394"></a>00394 <span class="preprocessor"></span> |
| <a name="l00395"></a>00395 <span class="comment">/* Run the below code for Cortex-M0 */</span> |
| <a name="l00396"></a>00396 |
| <a name="l00397"></a>00397 <span class="keywordflow">do</span> |
| <a name="l00398"></a>00398 { |
| <a name="l00399"></a>00399 <span class="comment">/* Reading the coefficients */</span> |
| <a name="l00400"></a>00400 b0 = *pCoeffs++; |
| <a name="l00401"></a>00401 b1 = *pCoeffs++; |
| <a name="l00402"></a>00402 b2 = *pCoeffs++; |
| <a name="l00403"></a>00403 a1 = *pCoeffs++; |
| <a name="l00404"></a>00404 a2 = *pCoeffs++; |
| <a name="l00405"></a>00405 |
| <a name="l00406"></a>00406 <span class="comment">/* Reading the state values */</span> |
| <a name="l00407"></a>00407 Xn1 = pState[0]; |
| <a name="l00408"></a>00408 Xn2 = pState[1]; |
| <a name="l00409"></a>00409 Yn1 = pState[2]; |
| <a name="l00410"></a>00410 Yn2 = pState[3]; |
| <a name="l00411"></a>00411 |
| <a name="l00412"></a>00412 <span class="comment">/* The variable acc hold output value that is being computed and </span> |
| <a name="l00413"></a>00413 <span class="comment"> * stored in the destination buffer </span> |
| <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> |
| <a name="l00415"></a>00415 <span class="comment"> */</span> |
| <a name="l00416"></a>00416 |
| <a name="l00417"></a>00417 sample = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>; |
| <a name="l00418"></a>00418 |
| <a name="l00419"></a>00419 <span class="keywordflow">while</span>(sample > 0u) |
| <a name="l00420"></a>00420 { |
| <a name="l00421"></a>00421 <span class="comment">/* Read the input */</span> |
| <a name="l00422"></a>00422 Xn = *pIn++; |
| <a name="l00423"></a>00423 |
| <a name="l00424"></a>00424 <span class="comment">/* The value is shifted to the MSB to perform 32x64 multiplication */</span> |
| <a name="l00425"></a>00425 Xn = Xn << 32; |
| <a name="l00426"></a>00426 |
| <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> |
| <a name="l00428"></a>00428 <span class="comment">/* acc = b0 * x[n] */</span> |
| <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); |
| <a name="l00430"></a>00430 <span class="comment">/* acc += b1 * x[n-1] */</span> |
| <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); |
| <a name="l00432"></a>00432 <span class="comment">/* acc += b[2] * x[n-2] */</span> |
| <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); |
| <a name="l00434"></a>00434 <span class="comment">/* acc += a1 * y[n-1] */</span> |
| <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); |
| <a name="l00436"></a>00436 <span class="comment">/* acc += a2 * y[n-2] */</span> |
| <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); |
| <a name="l00438"></a>00438 |
| <a name="l00439"></a>00439 <span class="comment">/* Every time after the output is computed state should be updated. */</span> |
| <a name="l00440"></a>00440 <span class="comment">/* The states should be updated as: */</span> |
| <a name="l00441"></a>00441 <span class="comment">/* Xn2 = Xn1 */</span> |
| <a name="l00442"></a>00442 <span class="comment">/* Xn1 = Xn */</span> |
| <a name="l00443"></a>00443 <span class="comment">/* Yn2 = Yn1 */</span> |
| <a name="l00444"></a>00444 <span class="comment">/* Yn1 = acc */</span> |
| <a name="l00445"></a>00445 Xn2 = Xn1; |
| <a name="l00446"></a>00446 Xn1 = Xn; |
| <a name="l00447"></a>00447 Yn2 = Yn1; |
| <a name="l00448"></a>00448 Yn1 = acc << shift; |
| <a name="l00449"></a>00449 |
| <a name="l00450"></a>00450 <span class="comment">/* Store the output in the destination buffer in 1.31 format. */</span> |
| <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)); |
| <a name="l00452"></a>00452 |
| <a name="l00453"></a>00453 <span class="comment">/* decrement the loop counter */</span> |
| <a name="l00454"></a>00454 sample--; |
| <a name="l00455"></a>00455 } |
| <a name="l00456"></a>00456 |
| <a name="l00457"></a>00457 <span class="comment">/* The first stage output is given as input to the second stage. */</span> |
| <a name="l00458"></a>00458 pIn = pDst; |
| <a name="l00459"></a>00459 |
| <a name="l00460"></a>00460 <span class="comment">/* Reset to destination buffer working pointer */</span> |
| <a name="l00461"></a>00461 pOut = pDst; |
| <a name="l00462"></a>00462 |
| <a name="l00463"></a>00463 <span class="comment">/* Store the updated state variables back into the pState array */</span> |
| <a name="l00464"></a>00464 *pState++ = Xn1; |
| <a name="l00465"></a>00465 *pState++ = Xn2; |
| <a name="l00466"></a>00466 *pState++ = Yn1; |
| <a name="l00467"></a>00467 *pState++ = Yn2; |
| <a name="l00468"></a>00468 |
| <a name="l00469"></a>00469 } <span class="keywordflow">while</span>(--stage); |
| <a name="l00470"></a>00470 |
| <a name="l00471"></a>00471 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span> |
| <a name="l00472"></a>00472 } |
| <a name="l00473"></a>00473 |
| </pre></div></div> |
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