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49 <div class="headertitle">
50 <h1>arm_iir_lattice_q31.c</h1> </div>
52 <div class="contents">
53 <a href="arm__iir__lattice__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_iir_lattice_q31.c </span>
61 <a name="l00009"></a>00009 <span class="comment">* </span>
62 <a name="l00010"></a>00010 <span class="comment">* Description: Q31 IIR lattice filter processing function. </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="l00062"></a><a class="code" href="group___i_i_r___lattice.html#ga123b26fa9156cd8d3622dd85931741ed">00062</a> <span class="keywordtype">void</span> <a class="code" href="group___i_i_r___lattice.html#ga123b26fa9156cd8d3622dd85931741ed" title="Processing function for the Q31 IIR lattice filter.">arm_iir_lattice_q31</a>(
88 <a name="l00063"></a>00063 <span class="keyword">const</span> <a class="code" href="structarm__iir__lattice__instance__q31.html" title="Instance structure for the Q31 IIR lattice filter.">arm_iir_lattice_instance_q31</a> * S,
89 <a name="l00064"></a>00064 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> * pSrc,
90 <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> * pDst,
91 <a name="l00066"></a>00066 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)
92 <a name="l00067"></a>00067 {
93 <a name="l00068"></a>00068 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> fcurr, fnext = 0, gcurr = 0, gnext; <span class="comment">/* Temporary variables for lattice stages */</span>
94 <a name="l00069"></a>00069 <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">/* Accumlator */</span>
95 <a name="l00070"></a>00070 uint32_t blkCnt, tapCnt; <span class="comment">/* Temporary variables for counts */</span>
96 <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> *px1, *px2, *pk, *pv; <span class="comment">/* Temporary pointers for state and coef */</span>
97 <a name="l00072"></a>00072 uint32_t numStages = S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a9df4570ed28c50fd9193ab654ff236ad">numStages</a>; <span class="comment">/* number of stages */</span>
98 <a name="l00073"></a>00073 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pState; <span class="comment">/* State pointer */</span>
99 <a name="l00074"></a>00074 <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">/* State current pointer */</span>
100 <a name="l00075"></a>00075
101 <a name="l00076"></a>00076 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
102 <a name="l00077"></a>00077
103 <a name="l00078"></a>00078 pState = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a941282745effd26a889fbfadf4b95e6a">pState</a>[0];
104 <a name="l00079"></a>00079
105 <a name="l00080"></a>00080
106 <a name="l00081"></a>00081 <span class="preprocessor">#ifndef ARM_MATH_CM0</span>
107 <a name="l00082"></a>00082 <span class="preprocessor"></span>
108 <a name="l00083"></a>00083 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
109 <a name="l00084"></a>00084
110 <a name="l00085"></a>00085 <span class="comment">/* Sample processing */</span>
111 <a name="l00086"></a>00086 <span class="keywordflow">while</span>(blkCnt > 0u)
112 <a name="l00087"></a>00087 {
113 <a name="l00088"></a>00088 <span class="comment">/* Read Sample from input buffer */</span>
114 <a name="l00089"></a>00089 <span class="comment">/* fN(n) = x(n) */</span>
115 <a name="l00090"></a>00090 fcurr = *pSrc++;
116 <a name="l00091"></a>00091
117 <a name="l00092"></a>00092 <span class="comment">/* Initialize state read pointer */</span>
118 <a name="l00093"></a>00093 px1 = pState;
119 <a name="l00094"></a>00094 <span class="comment">/* Initialize state write pointer */</span>
120 <a name="l00095"></a>00095 px2 = pState;
121 <a name="l00096"></a>00096 <span class="comment">/* Set accumulator to zero */</span>
122 <a name="l00097"></a>00097 acc = 0;
123 <a name="l00098"></a>00098 <span class="comment">/* Initialize Ladder coeff pointer */</span>
124 <a name="l00099"></a>00099 pv = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a04507e2b982b1dfa97b7b55752dea6b9">pvCoeffs</a>[0];
125 <a name="l00100"></a>00100 <span class="comment">/* Initialize Reflection coeff pointer */</span>
126 <a name="l00101"></a>00101 pk = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a1d30aa16aac7722936ea9dee59211863">pkCoeffs</a>[0];
127 <a name="l00102"></a>00102
128 <a name="l00103"></a>00103
129 <a name="l00104"></a>00104 <span class="comment">/* Process sample for first tap */</span>
130 <a name="l00105"></a>00105 gcurr = *px1++;
131 <a name="l00106"></a>00106 <span class="comment">/* fN-1(n) = fN(n) - kN * gN-1(n-1) */</span>
132 <a name="l00107"></a>00107 fnext = __QSUB(fcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31));
133 <a name="l00108"></a>00108 <span class="comment">/* gN(n) = kN * fN-1(n) + gN-1(n-1) */</span>
134 <a name="l00109"></a>00109 gnext = __QADD(gcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext * (*pk++)) >> 31));
135 <a name="l00110"></a>00110 <span class="comment">/* write gN-1(n-1) into state for next sample processing */</span>
136 <a name="l00111"></a>00111 *px2++ = gnext;
137 <a name="l00112"></a>00112 <span class="comment">/* y(n) += gN(n) * vN */</span>
138 <a name="l00113"></a>00113 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
139 <a name="l00114"></a>00114
140 <a name="l00115"></a>00115 <span class="comment">/* Update f values for next coefficient processing */</span>
141 <a name="l00116"></a>00116 fcurr = fnext;
142 <a name="l00117"></a>00117
143 <a name="l00118"></a>00118 <span class="comment">/* Loop unrolling. Process 4 taps at a time. */</span>
144 <a name="l00119"></a>00119 tapCnt = (numStages - 1u) >> 2;
145 <a name="l00120"></a>00120
146 <a name="l00121"></a>00121 <span class="keywordflow">while</span>(tapCnt > 0u)
147 <a name="l00122"></a>00122 {
148 <a name="l00123"></a>00123
149 <a name="l00124"></a>00124 <span class="comment">/* Process sample for 2nd, 6th .. taps */</span>
150 <a name="l00125"></a>00125 <span class="comment">/* Read gN-2(n-1) from state buffer */</span>
151 <a name="l00126"></a>00126 gcurr = *px1++;
152 <a name="l00127"></a>00127 <span class="comment">/* fN-2(n) = fN-1(n) - kN-1 * gN-2(n-1) */</span>
153 <a name="l00128"></a>00128 fnext = __QSUB(fcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31));
154 <a name="l00129"></a>00129 <span class="comment">/* gN-1(n) = kN-1 * fN-2(n) + gN-2(n-1) */</span>
155 <a name="l00130"></a>00130 gnext = __QADD(gcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext * (*pk++)) >> 31));
156 <a name="l00131"></a>00131 <span class="comment">/* y(n) += gN-1(n) * vN-1 */</span>
157 <a name="l00132"></a>00132 <span class="comment">/* process for gN-5(n) * vN-5, gN-9(n) * vN-9 ... */</span>
158 <a name="l00133"></a>00133 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
159 <a name="l00134"></a>00134 <span class="comment">/* write gN-1(n) into state for next sample processing */</span>
160 <a name="l00135"></a>00135 *px2++ = gnext;
161 <a name="l00136"></a>00136
162 <a name="l00137"></a>00137 <span class="comment">/* Process sample for 3nd, 7th ...taps */</span>
163 <a name="l00138"></a>00138 <span class="comment">/* Read gN-3(n-1) from state buffer */</span>
164 <a name="l00139"></a>00139 gcurr = *px1++;
165 <a name="l00140"></a>00140 <span class="comment">/* Process sample for 3rd, 7th .. taps */</span>
166 <a name="l00141"></a>00141 <span class="comment">/* fN-3(n) = fN-2(n) - kN-2 * gN-3(n-1) */</span>
167 <a name="l00142"></a>00142 fcurr = __QSUB(fnext, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31));
168 <a name="l00143"></a>00143 <span class="comment">/* gN-2(n) = kN-2 * fN-3(n) + gN-3(n-1) */</span>
169 <a name="l00144"></a>00144 gnext = __QADD(gcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fcurr * (*pk++)) >> 31));
170 <a name="l00145"></a>00145 <span class="comment">/* y(n) += gN-2(n) * vN-2 */</span>
171 <a name="l00146"></a>00146 <span class="comment">/* process for gN-6(n) * vN-6, gN-10(n) * vN-10 ... */</span>
172 <a name="l00147"></a>00147 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
173 <a name="l00148"></a>00148 <span class="comment">/* write gN-2(n) into state for next sample processing */</span>
174 <a name="l00149"></a>00149 *px2++ = gnext;
175 <a name="l00150"></a>00150
176 <a name="l00151"></a>00151
177 <a name="l00152"></a>00152 <span class="comment">/* Process sample for 4th, 8th ...taps */</span>
178 <a name="l00153"></a>00153 <span class="comment">/* Read gN-4(n-1) from state buffer */</span>
179 <a name="l00154"></a>00154 gcurr = *px1++;
180 <a name="l00155"></a>00155 <span class="comment">/* Process sample for 4th, 8th .. taps */</span>
181 <a name="l00156"></a>00156 <span class="comment">/* fN-4(n) = fN-3(n) - kN-3 * gN-4(n-1) */</span>
182 <a name="l00157"></a>00157 fnext = __QSUB(fcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31));
183 <a name="l00158"></a>00158 <span class="comment">/* gN-3(n) = kN-3 * fN-4(n) + gN-4(n-1) */</span>
184 <a name="l00159"></a>00159 gnext = __QADD(gcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext * (*pk++)) >> 31));
185 <a name="l00160"></a>00160 <span class="comment">/* y(n) += gN-3(n) * vN-3 */</span>
186 <a name="l00161"></a>00161 <span class="comment">/* process for gN-7(n) * vN-7, gN-11(n) * vN-11 ... */</span>
187 <a name="l00162"></a>00162 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
188 <a name="l00163"></a>00163 <span class="comment">/* write gN-3(n) into state for next sample processing */</span>
189 <a name="l00164"></a>00164 *px2++ = gnext;
190 <a name="l00165"></a>00165
191 <a name="l00166"></a>00166
192 <a name="l00167"></a>00167 <span class="comment">/* Process sample for 5th, 9th ...taps */</span>
193 <a name="l00168"></a>00168 <span class="comment">/* Read gN-5(n-1) from state buffer */</span>
194 <a name="l00169"></a>00169 gcurr = *px1++;
195 <a name="l00170"></a>00170 <span class="comment">/* Process sample for 5th, 9th .. taps */</span>
196 <a name="l00171"></a>00171 <span class="comment">/* fN-5(n) = fN-4(n) - kN-4 * gN-1(n-1) */</span>
197 <a name="l00172"></a>00172 fcurr = __QSUB(fnext, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31));
198 <a name="l00173"></a>00173 <span class="comment">/* gN-4(n) = kN-4 * fN-5(n) + gN-5(n-1) */</span>
199 <a name="l00174"></a>00174 gnext = __QADD(gcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fcurr * (*pk++)) >> 31));
200 <a name="l00175"></a>00175 <span class="comment">/* y(n) += gN-4(n) * vN-4 */</span>
201 <a name="l00176"></a>00176 <span class="comment">/* process for gN-8(n) * vN-8, gN-12(n) * vN-12 ... */</span>
202 <a name="l00177"></a>00177 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
203 <a name="l00178"></a>00178 <span class="comment">/* write gN-4(n) into state for next sample processing */</span>
204 <a name="l00179"></a>00179 *px2++ = gnext;
205 <a name="l00180"></a>00180
206 <a name="l00181"></a>00181 tapCnt--;
207 <a name="l00182"></a>00182
208 <a name="l00183"></a>00183 }
209 <a name="l00184"></a>00184
210 <a name="l00185"></a>00185 fnext = fcurr;
211 <a name="l00186"></a>00186
212 <a name="l00187"></a>00187 <span class="comment">/* If the filter length is not a multiple of 4, compute the remaining filter taps */</span>
213 <a name="l00188"></a>00188 tapCnt = (numStages - 1u) % 0x4u;
214 <a name="l00189"></a>00189
215 <a name="l00190"></a>00190 <span class="keywordflow">while</span>(tapCnt > 0u)
216 <a name="l00191"></a>00191 {
217 <a name="l00192"></a>00192 gcurr = *px1++;
218 <a name="l00193"></a>00193 <span class="comment">/* Process sample for last taps */</span>
219 <a name="l00194"></a>00194 fnext = __QSUB(fcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31));
220 <a name="l00195"></a>00195 gnext = __QADD(gcurr, (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext * (*pk++)) >> 31));
221 <a name="l00196"></a>00196 <span class="comment">/* Output samples for last taps */</span>
222 <a name="l00197"></a>00197 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
223 <a name="l00198"></a>00198 *px2++ = gnext;
224 <a name="l00199"></a>00199 fcurr = fnext;
225 <a name="l00200"></a>00200
226 <a name="l00201"></a>00201 tapCnt--;
227 <a name="l00202"></a>00202
228 <a name="l00203"></a>00203 }
229 <a name="l00204"></a>00204
230 <a name="l00205"></a>00205 <span class="comment">/* y(n) += g0(n) * v0 */</span>
231 <a name="l00206"></a>00206 acc += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext *(
232 <a name="l00207"></a>00207 *pv++);
233 <a name="l00208"></a>00208
234 <a name="l00209"></a>00209 *px2++ = fnext;
235 <a name="l00210"></a>00210
236 <a name="l00211"></a>00211 <span class="comment">/* write out into pDst */</span>
237 <a name="l00212"></a>00212 *pDst++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> 31u);
238 <a name="l00213"></a>00213
239 <a name="l00214"></a>00214 <span class="comment">/* Advance the state pointer by 4 to process the next group of 4 samples */</span>
240 <a name="l00215"></a>00215 pState = pState + 1u;
241 <a name="l00216"></a>00216 blkCnt--;
242 <a name="l00217"></a>00217
243 <a name="l00218"></a>00218 }
244 <a name="l00219"></a>00219
245 <a name="l00220"></a>00220 <span class="comment">/* Processing is complete. Now copy last S->numStages samples to start of the buffer </span>
246 <a name="l00221"></a>00221 <span class="comment"> for the preperation of next frame process */</span>
247 <a name="l00222"></a>00222
248 <a name="l00223"></a>00223 <span class="comment">/* Points to the start of the state buffer */</span>
249 <a name="l00224"></a>00224 pStateCurnt = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a941282745effd26a889fbfadf4b95e6a">pState</a>[0];
250 <a name="l00225"></a>00225 pState = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a941282745effd26a889fbfadf4b95e6a">pState</a>[<a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>];
251 <a name="l00226"></a>00226
252 <a name="l00227"></a>00227 tapCnt = numStages >> 2u;
253 <a name="l00228"></a>00228
254 <a name="l00229"></a>00229 <span class="comment">/* copy data */</span>
255 <a name="l00230"></a>00230 <span class="keywordflow">while</span>(tapCnt > 0u)
256 <a name="l00231"></a>00231 {
257 <a name="l00232"></a>00232 *pStateCurnt++ = *pState++;
258 <a name="l00233"></a>00233 *pStateCurnt++ = *pState++;
259 <a name="l00234"></a>00234 *pStateCurnt++ = *pState++;
260 <a name="l00235"></a>00235 *pStateCurnt++ = *pState++;
261 <a name="l00236"></a>00236
262 <a name="l00237"></a>00237 <span class="comment">/* Decrement the loop counter */</span>
263 <a name="l00238"></a>00238 tapCnt--;
264 <a name="l00239"></a>00239
265 <a name="l00240"></a>00240 }
266 <a name="l00241"></a>00241
267 <a name="l00242"></a>00242 <span class="comment">/* Calculate remaining number of copies */</span>
268 <a name="l00243"></a>00243 tapCnt = (numStages) % 0x4u;
269 <a name="l00244"></a>00244
270 <a name="l00245"></a>00245 <span class="comment">/* Copy the remaining q31_t data */</span>
271 <a name="l00246"></a>00246 <span class="keywordflow">while</span>(tapCnt > 0u)
272 <a name="l00247"></a>00247 {
273 <a name="l00248"></a>00248 *pStateCurnt++ = *pState++;
274 <a name="l00249"></a>00249
275 <a name="l00250"></a>00250 <span class="comment">/* Decrement the loop counter */</span>
276 <a name="l00251"></a>00251 tapCnt--;
277 <a name="l00252"></a>00252 };
278 <a name="l00253"></a>00253
279 <a name="l00254"></a>00254 <span class="preprocessor">#else</span>
280 <a name="l00255"></a>00255 <span class="preprocessor"></span>
281 <a name="l00256"></a>00256 <span class="comment">/* Run the below code for Cortex-M0 */</span>
282 <a name="l00257"></a>00257 <span class="comment">/* Sample processing */</span>
283 <a name="l00258"></a>00258 <span class="keywordflow">while</span>(blkCnt > 0u)
284 <a name="l00259"></a>00259 {
285 <a name="l00260"></a>00260 <span class="comment">/* Read Sample from input buffer */</span>
286 <a name="l00261"></a>00261 <span class="comment">/* fN(n) = x(n) */</span>
287 <a name="l00262"></a>00262 fcurr = *pSrc++;
288 <a name="l00263"></a>00263
289 <a name="l00264"></a>00264 <span class="comment">/* Initialize state read pointer */</span>
290 <a name="l00265"></a>00265 px1 = pState;
291 <a name="l00266"></a>00266 <span class="comment">/* Initialize state write pointer */</span>
292 <a name="l00267"></a>00267 px2 = pState;
293 <a name="l00268"></a>00268 <span class="comment">/* Set accumulator to zero */</span>
294 <a name="l00269"></a>00269 acc = 0;
295 <a name="l00270"></a>00270 <span class="comment">/* Initialize Ladder coeff pointer */</span>
296 <a name="l00271"></a>00271 pv = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a04507e2b982b1dfa97b7b55752dea6b9">pvCoeffs</a>[0];
297 <a name="l00272"></a>00272 <span class="comment">/* Initialize Reflection coeff pointer */</span>
298 <a name="l00273"></a>00273 pk = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a1d30aa16aac7722936ea9dee59211863">pkCoeffs</a>[0];
299 <a name="l00274"></a>00274
300 <a name="l00275"></a>00275 tapCnt = numStages;
301 <a name="l00276"></a>00276
302 <a name="l00277"></a>00277 <span class="keywordflow">while</span>(tapCnt > 0u)
303 <a name="l00278"></a>00278 {
304 <a name="l00279"></a>00279 gcurr = *px1++;
305 <a name="l00280"></a>00280 <span class="comment">/* Process sample */</span>
306 <a name="l00281"></a>00281 <span class="comment">/* fN-1(n) = fN(n) - kN * gN-1(n-1) */</span>
307 <a name="l00282"></a>00282 fnext =
308 <a name="l00283"></a>00283 <a class="code" href="arm__math_8h.html#ad7373e53d3c2e1adfeafc8c2e9720b5c" title="Clips Q63 to Q31 values.">clip_q63_to_q31</a>(((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fcurr -
309 <a name="l00284"></a>00284 ((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr * (*pk)) >> 31))));
310 <a name="l00285"></a>00285 <span class="comment">/* gN(n) = kN * fN-1(n) + gN-1(n-1) */</span>
311 <a name="l00286"></a>00286 gnext =
312 <a name="l00287"></a>00287 <a class="code" href="arm__math_8h.html#ad7373e53d3c2e1adfeafc8c2e9720b5c" title="Clips Q63 to Q31 values.">clip_q63_to_q31</a>(((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gcurr +
313 <a name="l00288"></a>00288 ((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext * (*pk++)) >> 31))));
314 <a name="l00289"></a>00289 <span class="comment">/* Output samples */</span>
315 <a name="l00290"></a>00290 <span class="comment">/* y(n) += gN(n) * vN */</span>
316 <a name="l00291"></a>00291 acc += ((<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) gnext * *pv++);
317 <a name="l00292"></a>00292 <span class="comment">/* write gN-1(n-1) into state for next sample processing */</span>
318 <a name="l00293"></a>00293 *px2++ = gnext;
319 <a name="l00294"></a>00294 <span class="comment">/* Update f values for next coefficient processing */</span>
320 <a name="l00295"></a>00295 fcurr = fnext;
321 <a name="l00296"></a>00296
322 <a name="l00297"></a>00297 tapCnt--;
323 <a name="l00298"></a>00298 }
324 <a name="l00299"></a>00299
325 <a name="l00300"></a>00300 <span class="comment">/* y(n) += g0(n) * v0 */</span>
326 <a name="l00301"></a>00301 acc += (<a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a>) fnext *(
327 <a name="l00302"></a>00302 *pv++);
328 <a name="l00303"></a>00303
329 <a name="l00304"></a>00304 *px2++ = fnext;
330 <a name="l00305"></a>00305
331 <a name="l00306"></a>00306 <span class="comment">/* write out into pDst */</span>
332 <a name="l00307"></a>00307 *pDst++ = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (acc >> 31u);
333 <a name="l00308"></a>00308
334 <a name="l00309"></a>00309 <span class="comment">/* Advance the state pointer by 1 to process the next group of samples */</span>
335 <a name="l00310"></a>00310 pState = pState + 1u;
336 <a name="l00311"></a>00311 blkCnt--;
337 <a name="l00312"></a>00312
338 <a name="l00313"></a>00313 }
339 <a name="l00314"></a>00314
340 <a name="l00315"></a>00315 <span class="comment">/* Processing is complete. Now copy last S->numStages samples to start of the buffer </span>
341 <a name="l00316"></a>00316 <span class="comment"> for the preperation of next frame process */</span>
342 <a name="l00317"></a>00317
343 <a name="l00318"></a>00318 <span class="comment">/* Points to the start of the state buffer */</span>
344 <a name="l00319"></a>00319 pStateCurnt = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a941282745effd26a889fbfadf4b95e6a">pState</a>[0];
345 <a name="l00320"></a>00320 pState = &S-><a class="code" href="structarm__iir__lattice__instance__q31.html#a941282745effd26a889fbfadf4b95e6a">pState</a>[<a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>];
346 <a name="l00321"></a>00321
347 <a name="l00322"></a>00322 tapCnt = numStages;
348 <a name="l00323"></a>00323
349 <a name="l00324"></a>00324 <span class="comment">/* Copy the remaining q31_t data */</span>
350 <a name="l00325"></a>00325 <span class="keywordflow">while</span>(tapCnt > 0u)
351 <a name="l00326"></a>00326 {
352 <a name="l00327"></a>00327 *pStateCurnt++ = *pState++;
353 <a name="l00328"></a>00328
354 <a name="l00329"></a>00329 <span class="comment">/* Decrement the loop counter */</span>
355 <a name="l00330"></a>00330 tapCnt--;
356 <a name="l00331"></a>00331 }
357 <a name="l00332"></a>00332
358 <a name="l00333"></a>00333 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
359 <a name="l00334"></a>00334
360 <a name="l00335"></a>00335 }
361 <a name="l00336"></a>00336
362 <a name="l00337"></a>00337
363 <a name="l00338"></a>00338
364 <a name="l00339"></a>00339
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