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49 <div class="headertitle">
50 <h1>arm_fir_interpolate_q31.c</h1> </div>
52 <div class="contents">
53 <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>
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_fir_interpolate_q31.c </span>
61 <a name="l00009"></a>00009 <span class="comment">* </span>
62 <a name="l00010"></a>00010 <span class="comment">* Description: Q31 FIR interpolation. </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 <span class="comment">* Version 0.0.7 2010/06/10 </span>
82 <a name="l00030"></a>00030 <span class="comment">* Misra-C changes done </span>
83 <a name="l00031"></a>00031 <span class="comment">* ---------------------------------------------------------------------------*/</span>
84 <a name="l00032"></a>00032
85 <a name="l00033"></a>00033 <span class="preprocessor">#include "<a class="code" href="arm__math_8h.html">arm_math.h</a>"</span>
86 <a name="l00034"></a>00034
87 <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>(
88 <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,
89 <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,
90 <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,
91 <a name="l00067"></a>00067 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)
92 <a name="l00068"></a>00068 {
93 <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>
94 <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>
95 <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>
96 <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>
97 <a name="l00073"></a>00073
98 <a name="l00074"></a>00074 <span class="preprocessor">#ifndef ARM_MATH_CM0</span>
99 <a name="l00075"></a>00075 <span class="preprocessor"></span>
100 <a name="l00076"></a>00076 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
101 <a name="l00077"></a>00077
102 <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>
103 <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>
104 <a name="l00080"></a>00080 uint32_t i, blkCnt, j; <span class="comment">/* Loop counters */</span>
105 <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>
106 <a name="l00082"></a>00082
107 <a name="l00083"></a>00083
108 <a name="l00084"></a>00084 <span class="comment">/* S->pState buffer contains previous frame (phaseLen - 1) samples */</span>
109 <a name="l00085"></a>00085 <span class="comment">/* pStateCurnt points to the location where the new input data should be written */</span>
110 <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);
111 <a name="l00087"></a>00087
112 <a name="l00088"></a>00088 <span class="comment">/* Total number of intput samples */</span>
113 <a name="l00089"></a>00089 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
114 <a name="l00090"></a>00090
115 <a name="l00091"></a>00091 <span class="comment">/* Loop over the blockSize. */</span>
116 <a name="l00092"></a>00092 <span class="keywordflow">while</span>(blkCnt > 0u)
117 <a name="l00093"></a>00093 {
118 <a name="l00094"></a>00094 <span class="comment">/* Copy new input sample into the state buffer */</span>
119 <a name="l00095"></a>00095 *pStateCurnt++ = *pSrc++;
120 <a name="l00096"></a>00096
121 <a name="l00097"></a>00097 <span class="comment">/* Address modifier index of coefficient buffer */</span>
122 <a name="l00098"></a>00098 j = 1u;
123 <a name="l00099"></a>00099
124 <a name="l00100"></a>00100 <span class="comment">/* Loop over the Interpolation factor. */</span>
125 <a name="l00101"></a>00101 i = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
126 <a name="l00102"></a>00102 <span class="keywordflow">while</span>(i > 0u)
127 <a name="l00103"></a>00103 {
128 <a name="l00104"></a>00104 <span class="comment">/* Set accumulator to zero */</span>
129 <a name="l00105"></a>00105 sum0 = 0;
130 <a name="l00106"></a>00106
131 <a name="l00107"></a>00107 <span class="comment">/* Initialize state pointer */</span>
132 <a name="l00108"></a>00108 ptr1 = pState;
133 <a name="l00109"></a>00109
134 <a name="l00110"></a>00110 <span class="comment">/* Initialize coefficient pointer */</span>
135 <a name="l00111"></a>00111 ptr2 = pCoeffs + (S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a> - j);
136 <a name="l00112"></a>00112
137 <a name="l00113"></a>00113 <span class="comment">/* Loop over the polyPhase length. Unroll by a factor of 4. </span>
138 <a name="l00114"></a>00114 <span class="comment"> ** Repeat until we've computed numTaps-(4*S->L) coefficients. */</span>
139 <a name="l00115"></a>00115 tapCnt = phaseLen >> 2;
140 <a name="l00116"></a>00116 <span class="keywordflow">while</span>(tapCnt > 0u)
141 <a name="l00117"></a>00117 {
142 <a name="l00118"></a>00118
143 <a name="l00119"></a>00119 <span class="comment">/* Read the coefficient */</span>
144 <a name="l00120"></a>00120 c0 = *(ptr2);
145 <a name="l00121"></a>00121
146 <a name="l00122"></a>00122 <span class="comment">/* Upsampling is done by stuffing L-1 zeros between each sample. </span>
147 <a name="l00123"></a>00123 <span class="comment"> * So instead of multiplying zeros with coefficients, </span>
148 <a name="l00124"></a>00124 <span class="comment"> * Increment the coefficient pointer by interpolation factor times. */</span>
149 <a name="l00125"></a>00125 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
150 <a name="l00126"></a>00126
151 <a name="l00127"></a>00127 <span class="comment">/* Read the input sample */</span>
152 <a name="l00128"></a>00128 x0 = *(ptr1++);
153 <a name="l00129"></a>00129
154 <a name="l00130"></a>00130 <span class="comment">/* Perform the multiply-accumulate */</span>
155 <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;
156 <a name="l00132"></a>00132
157 <a name="l00133"></a>00133 <span class="comment">/* Read the coefficient */</span>
158 <a name="l00134"></a>00134 c0 = *(ptr2);
159 <a name="l00135"></a>00135
160 <a name="l00136"></a>00136 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span>
161 <a name="l00137"></a>00137 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
162 <a name="l00138"></a>00138
163 <a name="l00139"></a>00139 <span class="comment">/* Read the input sample */</span>
164 <a name="l00140"></a>00140 x0 = *(ptr1++);
165 <a name="l00141"></a>00141
166 <a name="l00142"></a>00142 <span class="comment">/* Perform the multiply-accumulate */</span>
167 <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;
168 <a name="l00144"></a>00144
169 <a name="l00145"></a>00145 <span class="comment">/* Read the coefficient */</span>
170 <a name="l00146"></a>00146 c0 = *(ptr2);
171 <a name="l00147"></a>00147
172 <a name="l00148"></a>00148 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span>
173 <a name="l00149"></a>00149 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
174 <a name="l00150"></a>00150
175 <a name="l00151"></a>00151 <span class="comment">/* Read the input sample */</span>
176 <a name="l00152"></a>00152 x0 = *(ptr1++);
177 <a name="l00153"></a>00153
178 <a name="l00154"></a>00154 <span class="comment">/* Perform the multiply-accumulate */</span>
179 <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;
180 <a name="l00156"></a>00156
181 <a name="l00157"></a>00157 <span class="comment">/* Read the coefficient */</span>
182 <a name="l00158"></a>00158 c0 = *(ptr2);
183 <a name="l00159"></a>00159
184 <a name="l00160"></a>00160 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span>
185 <a name="l00161"></a>00161 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
186 <a name="l00162"></a>00162
187 <a name="l00163"></a>00163 <span class="comment">/* Read the input sample */</span>
188 <a name="l00164"></a>00164 x0 = *(ptr1++);
189 <a name="l00165"></a>00165
190 <a name="l00166"></a>00166 <span class="comment">/* Perform the multiply-accumulate */</span>
191 <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;
192 <a name="l00168"></a>00168
193 <a name="l00169"></a>00169 <span class="comment">/* Decrement the loop counter */</span>
194 <a name="l00170"></a>00170 tapCnt--;
195 <a name="l00171"></a>00171 }
196 <a name="l00172"></a>00172
197 <a name="l00173"></a>00173 <span class="comment">/* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */</span>
198 <a name="l00174"></a>00174 tapCnt = phaseLen & 0x3u;
199 <a name="l00175"></a>00175
200 <a name="l00176"></a>00176 <span class="keywordflow">while</span>(tapCnt > 0u)
201 <a name="l00177"></a>00177 {
202 <a name="l00178"></a>00178 <span class="comment">/* Read the coefficient */</span>
203 <a name="l00179"></a>00179 c0 = *(ptr2);
204 <a name="l00180"></a>00180
205 <a name="l00181"></a>00181 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span>
206 <a name="l00182"></a>00182 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
207 <a name="l00183"></a>00183
208 <a name="l00184"></a>00184 <span class="comment">/* Read the input sample */</span>
209 <a name="l00185"></a>00185 x0 = *(ptr1++);
210 <a name="l00186"></a>00186
211 <a name="l00187"></a>00187 <span class="comment">/* Perform the multiply-accumulate */</span>
212 <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;
213 <a name="l00189"></a>00189
214 <a name="l00190"></a>00190 <span class="comment">/* Decrement the loop counter */</span>
215 <a name="l00191"></a>00191 tapCnt--;
216 <a name="l00192"></a>00192 }
217 <a name="l00193"></a>00193
218 <a name="l00194"></a>00194 <span class="comment">/* The result is in the accumulator, store in the destination buffer. */</span>
219 <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);
220 <a name="l00196"></a>00196
221 <a name="l00197"></a>00197 <span class="comment">/* Increment the address modifier index of coefficient buffer */</span>
222 <a name="l00198"></a>00198 j++;
223 <a name="l00199"></a>00199
224 <a name="l00200"></a>00200 <span class="comment">/* Decrement the loop counter */</span>
225 <a name="l00201"></a>00201 i--;
226 <a name="l00202"></a>00202 }
227 <a name="l00203"></a>00203
228 <a name="l00204"></a>00204 <span class="comment">/* Advance the state pointer by 1 </span>
229 <a name="l00205"></a>00205 <span class="comment"> * to process the next group of interpolation factor number samples */</span>
230 <a name="l00206"></a>00206 pState = pState + 1;
231 <a name="l00207"></a>00207
232 <a name="l00208"></a>00208 <span class="comment">/* Decrement the loop counter */</span>
233 <a name="l00209"></a>00209 blkCnt--;
234 <a name="l00210"></a>00210 }
235 <a name="l00211"></a>00211
236 <a name="l00212"></a>00212 <span class="comment">/* Processing is complete. </span>
237 <a name="l00213"></a>00213 <span class="comment"> ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer. </span>
238 <a name="l00214"></a>00214 <span class="comment"> ** This prepares the state buffer for the next function call. */</span>
239 <a name="l00215"></a>00215
240 <a name="l00216"></a>00216 <span class="comment">/* Points to the start of the state buffer */</span>
241 <a name="l00217"></a>00217 pStateCurnt = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a>;
242 <a name="l00218"></a>00218
243 <a name="l00219"></a>00219 tapCnt = (phaseLen - 1u) >> 2u;
244 <a name="l00220"></a>00220
245 <a name="l00221"></a>00221 <span class="comment">/* copy data */</span>
246 <a name="l00222"></a>00222 <span class="keywordflow">while</span>(tapCnt > 0u)
247 <a name="l00223"></a>00223 {
248 <a name="l00224"></a>00224 *pStateCurnt++ = *pState++;
249 <a name="l00225"></a>00225 *pStateCurnt++ = *pState++;
250 <a name="l00226"></a>00226 *pStateCurnt++ = *pState++;
251 <a name="l00227"></a>00227 *pStateCurnt++ = *pState++;
252 <a name="l00228"></a>00228
253 <a name="l00229"></a>00229 <span class="comment">/* Decrement the loop counter */</span>
254 <a name="l00230"></a>00230 tapCnt--;
255 <a name="l00231"></a>00231 }
256 <a name="l00232"></a>00232
257 <a name="l00233"></a>00233 tapCnt = (phaseLen - 1u) % 0x04u;
258 <a name="l00234"></a>00234
259 <a name="l00235"></a>00235 <span class="comment">/* copy data */</span>
260 <a name="l00236"></a>00236 <span class="keywordflow">while</span>(tapCnt > 0u)
261 <a name="l00237"></a>00237 {
262 <a name="l00238"></a>00238 *pStateCurnt++ = *pState++;
263 <a name="l00239"></a>00239
264 <a name="l00240"></a>00240 <span class="comment">/* Decrement the loop counter */</span>
265 <a name="l00241"></a>00241 tapCnt--;
266 <a name="l00242"></a>00242 }
267 <a name="l00243"></a>00243
268 <a name="l00244"></a>00244 <span class="preprocessor">#else</span>
269 <a name="l00245"></a>00245 <span class="preprocessor"></span>
270 <a name="l00246"></a>00246 <span class="comment">/* Run the below code for Cortex-M0 */</span>
271 <a name="l00247"></a>00247
272 <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>
273 <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>
274 <a name="l00250"></a>00250 uint32_t i, blkCnt; <span class="comment">/* Loop counters */</span>
275 <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>
276 <a name="l00252"></a>00252
277 <a name="l00253"></a>00253
278 <a name="l00254"></a>00254 <span class="comment">/* S->pState buffer contains previous frame (phaseLen - 1) samples */</span>
279 <a name="l00255"></a>00255 <span class="comment">/* pStateCurnt points to the location where the new input data should be written */</span>
280 <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);
281 <a name="l00257"></a>00257
282 <a name="l00258"></a>00258 <span class="comment">/* Total number of intput samples */</span>
283 <a name="l00259"></a>00259 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
284 <a name="l00260"></a>00260
285 <a name="l00261"></a>00261 <span class="comment">/* Loop over the blockSize. */</span>
286 <a name="l00262"></a>00262 <span class="keywordflow">while</span>(blkCnt > 0u)
287 <a name="l00263"></a>00263 {
288 <a name="l00264"></a>00264 <span class="comment">/* Copy new input sample into the state buffer */</span>
289 <a name="l00265"></a>00265 *pStateCurnt++ = *pSrc++;
290 <a name="l00266"></a>00266
291 <a name="l00267"></a>00267 <span class="comment">/* Loop over the Interpolation factor. */</span>
292 <a name="l00268"></a>00268 i = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
293 <a name="l00269"></a>00269
294 <a name="l00270"></a>00270 <span class="keywordflow">while</span>(i > 0u)
295 <a name="l00271"></a>00271 {
296 <a name="l00272"></a>00272 <span class="comment">/* Set accumulator to zero */</span>
297 <a name="l00273"></a>00273 sum = 0;
298 <a name="l00274"></a>00274
299 <a name="l00275"></a>00275 <span class="comment">/* Initialize state pointer */</span>
300 <a name="l00276"></a>00276 ptr1 = pState;
301 <a name="l00277"></a>00277
302 <a name="l00278"></a>00278 <span class="comment">/* Initialize coefficient pointer */</span>
303 <a name="l00279"></a>00279 ptr2 = pCoeffs + (i - 1u);
304 <a name="l00280"></a>00280
305 <a name="l00281"></a>00281 tapCnt = phaseLen;
306 <a name="l00282"></a>00282
307 <a name="l00283"></a>00283 <span class="keywordflow">while</span>(tapCnt > 0u)
308 <a name="l00284"></a>00284 {
309 <a name="l00285"></a>00285 <span class="comment">/* Read the coefficient */</span>
310 <a name="l00286"></a>00286 c0 = *(ptr2);
311 <a name="l00287"></a>00287
312 <a name="l00288"></a>00288 <span class="comment">/* Increment the coefficient pointer by interpolation factor times. */</span>
313 <a name="l00289"></a>00289 ptr2 += S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#a5cdf0a631cb74e0e9588c388abe5235c">L</a>;
314 <a name="l00290"></a>00290
315 <a name="l00291"></a>00291 <span class="comment">/* Read the input sample */</span>
316 <a name="l00292"></a>00292 x0 = *ptr1++;
317 <a name="l00293"></a>00293
318 <a name="l00294"></a>00294 <span class="comment">/* Perform the multiply-accumulate */</span>
319 <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;
320 <a name="l00296"></a>00296
321 <a name="l00297"></a>00297 <span class="comment">/* Decrement the loop counter */</span>
322 <a name="l00298"></a>00298 tapCnt--;
323 <a name="l00299"></a>00299 }
324 <a name="l00300"></a>00300
325 <a name="l00301"></a>00301 <span class="comment">/* The result is in the accumulator, store in the destination buffer. */</span>
326 <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);
327 <a name="l00303"></a>00303
328 <a name="l00304"></a>00304 <span class="comment">/* Decrement the loop counter */</span>
329 <a name="l00305"></a>00305 i--;
330 <a name="l00306"></a>00306 }
331 <a name="l00307"></a>00307
332 <a name="l00308"></a>00308 <span class="comment">/* Advance the state pointer by 1 </span>
333 <a name="l00309"></a>00309 <span class="comment"> * to process the next group of interpolation factor number samples */</span>
334 <a name="l00310"></a>00310 pState = pState + 1;
335 <a name="l00311"></a>00311
336 <a name="l00312"></a>00312 <span class="comment">/* Decrement the loop counter */</span>
337 <a name="l00313"></a>00313 blkCnt--;
338 <a name="l00314"></a>00314 }
339 <a name="l00315"></a>00315
340 <a name="l00316"></a>00316 <span class="comment">/* Processing is complete. </span>
341 <a name="l00317"></a>00317 <span class="comment"> ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer. </span>
342 <a name="l00318"></a>00318 <span class="comment"> ** This prepares the state buffer for the next function call. */</span>
343 <a name="l00319"></a>00319
344 <a name="l00320"></a>00320 <span class="comment">/* Points to the start of the state buffer */</span>
345 <a name="l00321"></a>00321 pStateCurnt = S-><a class="code" href="structarm__fir__interpolate__instance__q31.html#addde04514b6e6ac72be3d609f0398b1a">pState</a>;
346 <a name="l00322"></a>00322
347 <a name="l00323"></a>00323 tapCnt = phaseLen - 1u;
348 <a name="l00324"></a>00324
349 <a name="l00325"></a>00325 <span class="comment">/* copy data */</span>
350 <a name="l00326"></a>00326 <span class="keywordflow">while</span>(tapCnt > 0u)
351 <a name="l00327"></a>00327 {
352 <a name="l00328"></a>00328 *pStateCurnt++ = *pState++;
353 <a name="l00329"></a>00329
354 <a name="l00330"></a>00330 <span class="comment">/* Decrement the loop counter */</span>
355 <a name="l00331"></a>00331 tapCnt--;
356 <a name="l00332"></a>00332 }
357 <a name="l00333"></a>00333
358 <a name="l00334"></a>00334 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
359 <a name="l00335"></a>00335
360 <a name="l00336"></a>00336 }
361 <a name="l00337"></a>00337
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