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49 <div class="headertitle">
50 <h1>arm_fir_lattice_q15.c</h1> </div>
52 <div class="contents">
53 <a href="arm__fir__lattice__q15_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_lattice_q15.c </span>
61 <a name="l00009"></a>00009 <span class="comment">* </span>
62 <a name="l00010"></a>00010 <span class="comment">* Description: Q15 FIR 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="l00054"></a><a class="code" href="group___f_i_r___lattice.html#gabb0ab07fd313b4d863070c3ddca51542">00054</a> <span class="keywordtype">void</span> <a class="code" href="group___f_i_r___lattice.html#gabb0ab07fd313b4d863070c3ddca51542" title="Processing function for the Q15 FIR lattice filter.">arm_fir_lattice_q15</a>(
88 <a name="l00055"></a>00055 <span class="keyword">const</span> <a class="code" href="structarm__fir__lattice__instance__q15.html" title="Instance structure for the Q15 FIR lattice filter.">arm_fir_lattice_instance_q15</a> * S,
89 <a name="l00056"></a>00056 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> * pSrc,
90 <a name="l00057"></a>00057 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> * pDst,
91 <a name="l00058"></a>00058 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)
92 <a name="l00059"></a>00059 {
93 <a name="l00060"></a>00060 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pState; <span class="comment">/* State pointer */</span>
94 <a name="l00061"></a>00061 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pCoeffs = S-><a class="code" href="structarm__fir__lattice__instance__q15.html#a78f872826140069cf67836fff87360bc">pCoeffs</a>; <span class="comment">/* Coefficient pointer */</span>
95 <a name="l00062"></a>00062 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *px; <span class="comment">/* temporary state pointer */</span>
96 <a name="l00063"></a>00063 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pk; <span class="comment">/* temporary coefficient pointer */</span>
97 <a name="l00064"></a>00064
98 <a name="l00065"></a>00065
99 <a name="l00066"></a>00066 <span class="preprocessor">#ifndef ARM_MATH_CM0</span>
100 <a name="l00067"></a>00067 <span class="preprocessor"></span>
101 <a name="l00068"></a>00068 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
102 <a name="l00069"></a>00069
103 <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> fcurnt1, fnext1, gcurnt1 = 0, gnext1; <span class="comment">/* temporary variables for first sample in loop unrolling */</span>
104 <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> fcurnt2, fnext2, gnext2; <span class="comment">/* temporary variables for second sample in loop unrolling */</span>
105 <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> fcurnt3, fnext3, gnext3; <span class="comment">/* temporary variables for third sample in loop unrolling */</span>
106 <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> fcurnt4, fnext4, gnext4; <span class="comment">/* temporary variables for fourth sample in loop unrolling */</span>
107 <a name="l00074"></a>00074 uint32_t numStages = S-><a class="code" href="structarm__fir__lattice__instance__q15.html#a38b179138d6a6c9cac4f8f79b6fd5357">numStages</a>; <span class="comment">/* Number of stages in the filter */</span>
108 <a name="l00075"></a>00075 uint32_t blkCnt, stageCnt; <span class="comment">/* temporary variables for counts */</span>
109 <a name="l00076"></a>00076
110 <a name="l00077"></a>00077 pState = &S-><a class="code" href="structarm__fir__lattice__instance__q15.html#a37b90dea2bc3ee7c9951a9fe74db0cbb">pState</a>[0];
111 <a name="l00078"></a>00078
112 <a name="l00079"></a>00079 blkCnt = blockSize >> 2u;
113 <a name="l00080"></a>00080
114 <a name="l00081"></a>00081 <span class="comment">/* First part of the processing with loop unrolling. Compute 4 outputs at a time. </span>
115 <a name="l00082"></a>00082 <span class="comment"> ** a second loop below computes the remaining 1 to 3 samples. */</span>
116 <a name="l00083"></a>00083 <span class="keywordflow">while</span>(blkCnt > 0u)
117 <a name="l00084"></a>00084 {
118 <a name="l00085"></a>00085
119 <a name="l00086"></a>00086 <span class="comment">/* Read two samples from input buffer */</span>
120 <a name="l00087"></a>00087 <span class="comment">/* f0(n) = x(n) */</span>
121 <a name="l00088"></a>00088 fcurnt1 = *pSrc++;
122 <a name="l00089"></a>00089 fcurnt2 = *pSrc++;
123 <a name="l00090"></a>00090
124 <a name="l00091"></a>00091 <span class="comment">/* Initialize coeff pointer */</span>
125 <a name="l00092"></a>00092 pk = (pCoeffs);
126 <a name="l00093"></a>00093
127 <a name="l00094"></a>00094 <span class="comment">/* Initialize state pointer */</span>
128 <a name="l00095"></a>00095 px = pState;
129 <a name="l00096"></a>00096
130 <a name="l00097"></a>00097 <span class="comment">/* Read g0(n-1) from state */</span>
131 <a name="l00098"></a>00098 gcurnt1 = *px;
132 <a name="l00099"></a>00099
133 <a name="l00100"></a>00100 <span class="comment">/* Process first sample for first tap */</span>
134 <a name="l00101"></a>00101 <span class="comment">/* f1(n) = f0(n) + K1 * g0(n-1) */</span>
135 <a name="l00102"></a>00102 fnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
136 <a name="l00103"></a>00103 fnext1 = __SSAT(fnext1, 16);
137 <a name="l00104"></a>00104
138 <a name="l00105"></a>00105 <span class="comment">/* g1(n) = f0(n) * K1 + g0(n-1) */</span>
139 <a name="l00106"></a>00106 gnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt1 * (*pk)) >> 15u) + gcurnt1;
140 <a name="l00107"></a>00107 gnext1 = __SSAT(gnext1, 16);
141 <a name="l00108"></a>00108
142 <a name="l00109"></a>00109 <span class="comment">/* Process second sample for first tap */</span>
143 <a name="l00110"></a>00110 <span class="comment">/* for sample 2 processing */</span>
144 <a name="l00111"></a>00111 fnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt1 * (*pk)) >> 15u) + fcurnt2;
145 <a name="l00112"></a>00112 fnext2 = __SSAT(fnext2, 16);
146 <a name="l00113"></a>00113
147 <a name="l00114"></a>00114 gnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt2 * (*pk)) >> 15u) + fcurnt1;
148 <a name="l00115"></a>00115 gnext2 = __SSAT(gnext2, 16);
149 <a name="l00116"></a>00116
150 <a name="l00117"></a>00117
151 <a name="l00118"></a>00118 <span class="comment">/* Read next two samples from input buffer */</span>
152 <a name="l00119"></a>00119 <span class="comment">/* f0(n+2) = x(n+2) */</span>
153 <a name="l00120"></a>00120 fcurnt3 = *pSrc++;
154 <a name="l00121"></a>00121 fcurnt4 = *pSrc++;
155 <a name="l00122"></a>00122
156 <a name="l00123"></a>00123 <span class="comment">/* Copy only last input samples into the state buffer </span>
157 <a name="l00124"></a>00124 <span class="comment"> which is used for next four samples processing */</span>
158 <a name="l00125"></a>00125 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) fcurnt4;
159 <a name="l00126"></a>00126
160 <a name="l00127"></a>00127 <span class="comment">/* Process third sample for first tap */</span>
161 <a name="l00128"></a>00128 fnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt2 * (*pk)) >> 15u) + fcurnt3;
162 <a name="l00129"></a>00129 fnext3 = __SSAT(fnext3, 16);
163 <a name="l00130"></a>00130 gnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt3 * (*pk)) >> 15u) + fcurnt2;
164 <a name="l00131"></a>00131 gnext3 = __SSAT(gnext3, 16);
165 <a name="l00132"></a>00132
166 <a name="l00133"></a>00133 <span class="comment">/* Process fourth sample for first tap */</span>
167 <a name="l00134"></a>00134 fnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt3 * (*pk)) >> 15u) + fcurnt4;
168 <a name="l00135"></a>00135 fnext4 = __SSAT(fnext4, 16);
169 <a name="l00136"></a>00136 gnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt4 * (*pk++)) >> 15u) + fcurnt3;
170 <a name="l00137"></a>00137 gnext4 = __SSAT(gnext4, 16);
171 <a name="l00138"></a>00138
172 <a name="l00139"></a>00139 <span class="comment">/* Update of f values for next coefficient set processing */</span>
173 <a name="l00140"></a>00140 fcurnt1 = fnext1;
174 <a name="l00141"></a>00141 fcurnt2 = fnext2;
175 <a name="l00142"></a>00142 fcurnt3 = fnext3;
176 <a name="l00143"></a>00143 fcurnt4 = fnext4;
177 <a name="l00144"></a>00144
178 <a name="l00145"></a>00145
179 <a name="l00146"></a>00146 <span class="comment">/* Loop unrolling. Process 4 taps at a time . */</span>
180 <a name="l00147"></a>00147 stageCnt = (numStages - 1u) >> 2;
181 <a name="l00148"></a>00148
182 <a name="l00149"></a>00149
183 <a name="l00150"></a>00150 <span class="comment">/* Loop over the number of taps. Unroll by a factor of 4. </span>
184 <a name="l00151"></a>00151 <span class="comment"> ** Repeat until we've computed numStages-3 coefficients. */</span>
185 <a name="l00152"></a>00152
186 <a name="l00153"></a>00153 <span class="comment">/* Process 2nd, 3rd, 4th and 5th taps ... here */</span>
187 <a name="l00154"></a>00154 <span class="keywordflow">while</span>(stageCnt > 0u)
188 <a name="l00155"></a>00155 {
189 <a name="l00156"></a>00156 <span class="comment">/* Read g1(n-1), g3(n-1) .... from state */</span>
190 <a name="l00157"></a>00157 gcurnt1 = *px;
191 <a name="l00158"></a>00158
192 <a name="l00159"></a>00159 <span class="comment">/* save g1(n) in state buffer */</span>
193 <a name="l00160"></a>00160 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext4;
194 <a name="l00161"></a>00161
195 <a name="l00162"></a>00162 <span class="comment">/* Process first sample for 2nd, 6th .. tap */</span>
196 <a name="l00163"></a>00163 <span class="comment">/* Sample processing for K2, K6.... */</span>
197 <a name="l00164"></a>00164 <span class="comment">/* f1(n) = f0(n) + K1 * g0(n-1) */</span>
198 <a name="l00165"></a>00165 fnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
199 <a name="l00166"></a>00166 fnext1 = __SSAT(fnext1, 16);
200 <a name="l00167"></a>00167
201 <a name="l00168"></a>00168
202 <a name="l00169"></a>00169 <span class="comment">/* Process second sample for 2nd, 6th .. tap */</span>
203 <a name="l00170"></a>00170 <span class="comment">/* for sample 2 processing */</span>
204 <a name="l00171"></a>00171 fnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
205 <a name="l00172"></a>00172 fnext2 = __SSAT(fnext2, 16);
206 <a name="l00173"></a>00173 <span class="comment">/* Process third sample for 2nd, 6th .. tap */</span>
207 <a name="l00174"></a>00174 fnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
208 <a name="l00175"></a>00175 fnext3 = __SSAT(fnext3, 16);
209 <a name="l00176"></a>00176 <span class="comment">/* Process fourth sample for 2nd, 6th .. tap */</span>
210 <a name="l00177"></a>00177 <span class="comment">/* fnext4 = fcurnt4 + (*pk) * gnext3; */</span>
211 <a name="l00178"></a>00178 fnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
212 <a name="l00179"></a>00179 fnext4 = __SSAT(fnext4, 16);
213 <a name="l00180"></a>00180
214 <a name="l00181"></a>00181 <span class="comment">/* g1(n) = f0(n) * K1 + g0(n-1) */</span>
215 <a name="l00182"></a>00182 <span class="comment">/* Calculation of state values for next stage */</span>
216 <a name="l00183"></a>00183 gnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
217 <a name="l00184"></a>00184 gnext4 = __SSAT(gnext4, 16);
218 <a name="l00185"></a>00185 gnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
219 <a name="l00186"></a>00186 gnext3 = __SSAT(gnext3, 16);
220 <a name="l00187"></a>00187
221 <a name="l00188"></a>00188 gnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
222 <a name="l00189"></a>00189 gnext2 = __SSAT(gnext2, 16);
223 <a name="l00190"></a>00190
224 <a name="l00191"></a>00191 gnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
225 <a name="l00192"></a>00192 gnext1 = __SSAT(gnext1, 16);
226 <a name="l00193"></a>00193
227 <a name="l00194"></a>00194
228 <a name="l00195"></a>00195 <span class="comment">/* Read g2(n-1), g4(n-1) .... from state */</span>
229 <a name="l00196"></a>00196 gcurnt1 = *px;
230 <a name="l00197"></a>00197
231 <a name="l00198"></a>00198 <span class="comment">/* save g1(n) in state buffer */</span>
232 <a name="l00199"></a>00199 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext4;
233 <a name="l00200"></a>00200
234 <a name="l00201"></a>00201 <span class="comment">/* Sample processing for K3, K7.... */</span>
235 <a name="l00202"></a>00202 <span class="comment">/* Process first sample for 3rd, 7th .. tap */</span>
236 <a name="l00203"></a>00203 <span class="comment">/* f3(n) = f2(n) + K3 * g2(n-1) */</span>
237 <a name="l00204"></a>00204 fcurnt1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gcurnt1 * (*pk)) >> 15u) + fnext1;
238 <a name="l00205"></a>00205 fcurnt1 = __SSAT(fcurnt1, 16);
239 <a name="l00206"></a>00206
240 <a name="l00207"></a>00207 <span class="comment">/* Process second sample for 3rd, 7th .. tap */</span>
241 <a name="l00208"></a>00208 fcurnt2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext1 * (*pk)) >> 15u) + fnext2;
242 <a name="l00209"></a>00209 fcurnt2 = __SSAT(fcurnt2, 16);
243 <a name="l00210"></a>00210
244 <a name="l00211"></a>00211 <span class="comment">/* Process third sample for 3rd, 7th .. tap */</span>
245 <a name="l00212"></a>00212 fcurnt3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext2 * (*pk)) >> 15u) + fnext3;
246 <a name="l00213"></a>00213 fcurnt3 = __SSAT(fcurnt3, 16);
247 <a name="l00214"></a>00214
248 <a name="l00215"></a>00215 <span class="comment">/* Process fourth sample for 3rd, 7th .. tap */</span>
249 <a name="l00216"></a>00216 fcurnt4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext3 * (*pk)) >> 15u) + fnext4;
250 <a name="l00217"></a>00217 fcurnt4 = __SSAT(fcurnt4, 16);
251 <a name="l00218"></a>00218
252 <a name="l00219"></a>00219 <span class="comment">/* Calculation of state values for next stage */</span>
253 <a name="l00220"></a>00220 <span class="comment">/* g3(n) = f2(n) * K3 + g2(n-1) */</span>
254 <a name="l00221"></a>00221 gnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext4 * (*pk)) >> 15u) + gnext3;
255 <a name="l00222"></a>00222 gnext4 = __SSAT(gnext4, 16);
256 <a name="l00223"></a>00223
257 <a name="l00224"></a>00224 gnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext3 * (*pk)) >> 15u) + gnext2;
258 <a name="l00225"></a>00225 gnext3 = __SSAT(gnext3, 16);
259 <a name="l00226"></a>00226
260 <a name="l00227"></a>00227 gnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext2 * (*pk)) >> 15u) + gnext1;
261 <a name="l00228"></a>00228 gnext2 = __SSAT(gnext2, 16);
262 <a name="l00229"></a>00229
263 <a name="l00230"></a>00230 gnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext1 * (*pk++)) >> 15u) + gcurnt1;
264 <a name="l00231"></a>00231 gnext1 = __SSAT(gnext1, 16);
265 <a name="l00232"></a>00232
266 <a name="l00233"></a>00233 <span class="comment">/* Read g1(n-1), g3(n-1) .... from state */</span>
267 <a name="l00234"></a>00234 gcurnt1 = *px;
268 <a name="l00235"></a>00235
269 <a name="l00236"></a>00236 <span class="comment">/* save g1(n) in state buffer */</span>
270 <a name="l00237"></a>00237 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext4;
271 <a name="l00238"></a>00238
272 <a name="l00239"></a>00239 <span class="comment">/* Sample processing for K4, K8.... */</span>
273 <a name="l00240"></a>00240 <span class="comment">/* Process first sample for 4th, 8th .. tap */</span>
274 <a name="l00241"></a>00241 <span class="comment">/* f4(n) = f3(n) + K4 * g3(n-1) */</span>
275 <a name="l00242"></a>00242 fnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
276 <a name="l00243"></a>00243 fnext1 = __SSAT(fnext1, 16);
277 <a name="l00244"></a>00244
278 <a name="l00245"></a>00245 <span class="comment">/* Process second sample for 4th, 8th .. tap */</span>
279 <a name="l00246"></a>00246 <span class="comment">/* for sample 2 processing */</span>
280 <a name="l00247"></a>00247 fnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
281 <a name="l00248"></a>00248 fnext2 = __SSAT(fnext2, 16);
282 <a name="l00249"></a>00249
283 <a name="l00250"></a>00250 <span class="comment">/* Process third sample for 4th, 8th .. tap */</span>
284 <a name="l00251"></a>00251 fnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
285 <a name="l00252"></a>00252 fnext3 = __SSAT(fnext3, 16);
286 <a name="l00253"></a>00253
287 <a name="l00254"></a>00254 <span class="comment">/* Process fourth sample for 4th, 8th .. tap */</span>
288 <a name="l00255"></a>00255 fnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
289 <a name="l00256"></a>00256 fnext4 = __SSAT(fnext4, 16);
290 <a name="l00257"></a>00257
291 <a name="l00258"></a>00258 <span class="comment">/* g4(n) = f3(n) * K4 + g3(n-1) */</span>
292 <a name="l00259"></a>00259 <span class="comment">/* Calculation of state values for next stage */</span>
293 <a name="l00260"></a>00260 gnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
294 <a name="l00261"></a>00261 gnext4 = __SSAT(gnext4, 16);
295 <a name="l00262"></a>00262
296 <a name="l00263"></a>00263 gnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
297 <a name="l00264"></a>00264 gnext3 = __SSAT(gnext3, 16);
298 <a name="l00265"></a>00265
299 <a name="l00266"></a>00266 gnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
300 <a name="l00267"></a>00267 gnext2 = __SSAT(gnext2, 16);
301 <a name="l00268"></a>00268 gnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
302 <a name="l00269"></a>00269 gnext1 = __SSAT(gnext1, 16);
303 <a name="l00270"></a>00270
304 <a name="l00271"></a>00271
305 <a name="l00272"></a>00272 <span class="comment">/* Read g2(n-1), g4(n-1) .... from state */</span>
306 <a name="l00273"></a>00273 gcurnt1 = *px;
307 <a name="l00274"></a>00274
308 <a name="l00275"></a>00275 <span class="comment">/* save g4(n) in state buffer */</span>
309 <a name="l00276"></a>00276 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext4;
310 <a name="l00277"></a>00277
311 <a name="l00278"></a>00278 <span class="comment">/* Sample processing for K5, K9.... */</span>
312 <a name="l00279"></a>00279 <span class="comment">/* Process first sample for 5th, 9th .. tap */</span>
313 <a name="l00280"></a>00280 <span class="comment">/* f5(n) = f4(n) + K5 * g4(n-1) */</span>
314 <a name="l00281"></a>00281 fcurnt1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gcurnt1 * (*pk)) >> 15u) + fnext1;
315 <a name="l00282"></a>00282 fcurnt1 = __SSAT(fcurnt1, 16);
316 <a name="l00283"></a>00283
317 <a name="l00284"></a>00284 <span class="comment">/* Process second sample for 5th, 9th .. tap */</span>
318 <a name="l00285"></a>00285 fcurnt2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext1 * (*pk)) >> 15u) + fnext2;
319 <a name="l00286"></a>00286 fcurnt2 = __SSAT(fcurnt2, 16);
320 <a name="l00287"></a>00287
321 <a name="l00288"></a>00288 <span class="comment">/* Process third sample for 5th, 9th .. tap */</span>
322 <a name="l00289"></a>00289 fcurnt3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext2 * (*pk)) >> 15u) + fnext3;
323 <a name="l00290"></a>00290 fcurnt3 = __SSAT(fcurnt3, 16);
324 <a name="l00291"></a>00291
325 <a name="l00292"></a>00292 <span class="comment">/* Process fourth sample for 5th, 9th .. tap */</span>
326 <a name="l00293"></a>00293 fcurnt4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext3 * (*pk)) >> 15u) + fnext4;
327 <a name="l00294"></a>00294 fcurnt4 = __SSAT(fcurnt4, 16);
328 <a name="l00295"></a>00295
329 <a name="l00296"></a>00296 <span class="comment">/* Calculation of state values for next stage */</span>
330 <a name="l00297"></a>00297 <span class="comment">/* g5(n) = f4(n) * K5 + g4(n-1) */</span>
331 <a name="l00298"></a>00298 gnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext4 * (*pk)) >> 15u) + gnext3;
332 <a name="l00299"></a>00299 gnext4 = __SSAT(gnext4, 16);
333 <a name="l00300"></a>00300 gnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext3 * (*pk)) >> 15u) + gnext2;
334 <a name="l00301"></a>00301 gnext3 = __SSAT(gnext3, 16);
335 <a name="l00302"></a>00302 gnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext2 * (*pk)) >> 15u) + gnext1;
336 <a name="l00303"></a>00303 gnext2 = __SSAT(gnext2, 16);
337 <a name="l00304"></a>00304 gnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fnext1 * (*pk++)) >> 15u) + gcurnt1;
338 <a name="l00305"></a>00305 gnext1 = __SSAT(gnext1, 16);
339 <a name="l00306"></a>00306
340 <a name="l00307"></a>00307 stageCnt--;
341 <a name="l00308"></a>00308 }
342 <a name="l00309"></a>00309
343 <a name="l00310"></a>00310 <span class="comment">/* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */</span>
344 <a name="l00311"></a>00311 stageCnt = (numStages - 1u) % 0x4u;
345 <a name="l00312"></a>00312
346 <a name="l00313"></a>00313 <span class="keywordflow">while</span>(stageCnt > 0u)
347 <a name="l00314"></a>00314 {
348 <a name="l00315"></a>00315 gcurnt1 = *px;
349 <a name="l00316"></a>00316
350 <a name="l00317"></a>00317 <span class="comment">/* save g value in state buffer */</span>
351 <a name="l00318"></a>00318 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext4;
352 <a name="l00319"></a>00319
353 <a name="l00320"></a>00320 <span class="comment">/* Process four samples for last three taps here */</span>
354 <a name="l00321"></a>00321 fnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
355 <a name="l00322"></a>00322 fnext1 = __SSAT(fnext1, 16);
356 <a name="l00323"></a>00323 fnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
357 <a name="l00324"></a>00324 fnext2 = __SSAT(fnext2, 16);
358 <a name="l00325"></a>00325
359 <a name="l00326"></a>00326 fnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
360 <a name="l00327"></a>00327 fnext3 = __SSAT(fnext3, 16);
361 <a name="l00328"></a>00328
362 <a name="l00329"></a>00329 fnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
363 <a name="l00330"></a>00330 fnext4 = __SSAT(fnext4, 16);
364 <a name="l00331"></a>00331
365 <a name="l00332"></a>00332 <span class="comment">/* g1(n) = f0(n) * K1 + g0(n-1) */</span>
366 <a name="l00333"></a>00333 gnext4 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
367 <a name="l00334"></a>00334 gnext4 = __SSAT(gnext4, 16);
368 <a name="l00335"></a>00335 gnext3 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
369 <a name="l00336"></a>00336 gnext3 = __SSAT(gnext3, 16);
370 <a name="l00337"></a>00337 gnext2 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
371 <a name="l00338"></a>00338 gnext2 = __SSAT(gnext2, 16);
372 <a name="l00339"></a>00339 gnext1 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
373 <a name="l00340"></a>00340 gnext1 = __SSAT(gnext1, 16);
374 <a name="l00341"></a>00341
375 <a name="l00342"></a>00342 <span class="comment">/* Update of f values for next coefficient set processing */</span>
376 <a name="l00343"></a>00343 fcurnt1 = fnext1;
377 <a name="l00344"></a>00344 fcurnt2 = fnext2;
378 <a name="l00345"></a>00345 fcurnt3 = fnext3;
379 <a name="l00346"></a>00346 fcurnt4 = fnext4;
380 <a name="l00347"></a>00347
381 <a name="l00348"></a>00348 stageCnt--;
382 <a name="l00349"></a>00349
383 <a name="l00350"></a>00350 }
384 <a name="l00351"></a>00351
385 <a name="l00352"></a>00352 <span class="comment">/* The results in the 4 accumulators, store in the destination buffer. */</span>
386 <a name="l00353"></a>00353 <span class="comment">/* y(n) = fN(n) */</span>
387 <a name="l00354"></a>00354
388 <a name="l00355"></a>00355 <span class="preprocessor">#ifndef ARM_MATH_BIG_ENDIAN</span>
389 <a name="l00356"></a>00356 <span class="preprocessor"></span>
390 <a name="l00357"></a>00357 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pDst)++ = __PKHBT(fcurnt1, fcurnt2, 16);
391 <a name="l00358"></a>00358 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pDst)++ = __PKHBT(fcurnt3, fcurnt4, 16);
392 <a name="l00359"></a>00359
393 <a name="l00360"></a>00360 <span class="preprocessor">#else</span>
394 <a name="l00361"></a>00361 <span class="preprocessor"></span>
395 <a name="l00362"></a>00362 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pDst)++ = __PKHBT(fcurnt2, fcurnt1, 16);
396 <a name="l00363"></a>00363 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pDst)++ = __PKHBT(fcurnt4, fcurnt3, 16);
397 <a name="l00364"></a>00364
398 <a name="l00365"></a>00365 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_BIG_ENDIAN */</span>
399 <a name="l00366"></a>00366
400 <a name="l00367"></a>00367 blkCnt--;
401 <a name="l00368"></a>00368 }
402 <a name="l00369"></a>00369
403 <a name="l00370"></a>00370 <span class="comment">/* If the blockSize is not a multiple of 4, compute any remaining output samples here. </span>
404 <a name="l00371"></a>00371 <span class="comment"> ** No loop unrolling is used. */</span>
405 <a name="l00372"></a>00372 blkCnt = blockSize % 0x4u;
406 <a name="l00373"></a>00373
407 <a name="l00374"></a>00374 <span class="keywordflow">while</span>(blkCnt > 0u)
408 <a name="l00375"></a>00375 {
409 <a name="l00376"></a>00376 <span class="comment">/* f0(n) = x(n) */</span>
410 <a name="l00377"></a>00377 fcurnt1 = *pSrc++;
411 <a name="l00378"></a>00378
412 <a name="l00379"></a>00379 <span class="comment">/* Initialize coeff pointer */</span>
413 <a name="l00380"></a>00380 pk = (pCoeffs);
414 <a name="l00381"></a>00381
415 <a name="l00382"></a>00382 <span class="comment">/* Initialize state pointer */</span>
416 <a name="l00383"></a>00383 px = pState;
417 <a name="l00384"></a>00384
418 <a name="l00385"></a>00385 <span class="comment">/* read g2(n) from state buffer */</span>
419 <a name="l00386"></a>00386 gcurnt1 = *px;
420 <a name="l00387"></a>00387
421 <a name="l00388"></a>00388 <span class="comment">/* for sample 1 processing */</span>
422 <a name="l00389"></a>00389 <span class="comment">/* f1(n) = f0(n) + K1 * g0(n-1) */</span>
423 <a name="l00390"></a>00390 fnext1 = (((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) gcurnt1 * (*pk)) >> 15u) + fcurnt1;
424 <a name="l00391"></a>00391 fnext1 = __SSAT(fnext1, 16);
425 <a name="l00392"></a>00392
426 <a name="l00393"></a>00393
427 <a name="l00394"></a>00394 <span class="comment">/* g1(n) = f0(n) * K1 + g0(n-1) */</span>
428 <a name="l00395"></a>00395 gnext1 = (((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
429 <a name="l00396"></a>00396 gnext1 = __SSAT(gnext1, 16);
430 <a name="l00397"></a>00397
431 <a name="l00398"></a>00398 <span class="comment">/* save g1(n) in state buffer */</span>
432 <a name="l00399"></a>00399 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) fcurnt1;
433 <a name="l00400"></a>00400
434 <a name="l00401"></a>00401 <span class="comment">/* f1(n) is saved in fcurnt1 </span>
435 <a name="l00402"></a>00402 <span class="comment"> for next stage processing */</span>
436 <a name="l00403"></a>00403 fcurnt1 = fnext1;
437 <a name="l00404"></a>00404
438 <a name="l00405"></a>00405 stageCnt = (numStages - 1u);
439 <a name="l00406"></a>00406
440 <a name="l00407"></a>00407 <span class="comment">/* stage loop */</span>
441 <a name="l00408"></a>00408 <span class="keywordflow">while</span>(stageCnt > 0u)
442 <a name="l00409"></a>00409 {
443 <a name="l00410"></a>00410 <span class="comment">/* read g2(n) from state buffer */</span>
444 <a name="l00411"></a>00411 gcurnt1 = *px;
445 <a name="l00412"></a>00412
446 <a name="l00413"></a>00413 <span class="comment">/* save g1(n) in state buffer */</span>
447 <a name="l00414"></a>00414 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext1;
448 <a name="l00415"></a>00415
449 <a name="l00416"></a>00416 <span class="comment">/* Sample processing for K2, K3.... */</span>
450 <a name="l00417"></a>00417 <span class="comment">/* f2(n) = f1(n) + K2 * g1(n-1) */</span>
451 <a name="l00418"></a>00418 fnext1 = (((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) gcurnt1 * (*pk)) >> 15u) + fcurnt1;
452 <a name="l00419"></a>00419 fnext1 = __SSAT(fnext1, 16);
453 <a name="l00420"></a>00420
454 <a name="l00421"></a>00421 <span class="comment">/* g2(n) = f1(n) * K2 + g1(n-1) */</span>
455 <a name="l00422"></a>00422 gnext1 = (((<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
456 <a name="l00423"></a>00423 gnext1 = __SSAT(gnext1, 16);
457 <a name="l00424"></a>00424
458 <a name="l00425"></a>00425
459 <a name="l00426"></a>00426 <span class="comment">/* f1(n) is saved in fcurnt1 </span>
460 <a name="l00427"></a>00427 <span class="comment"> for next stage processing */</span>
461 <a name="l00428"></a>00428 fcurnt1 = fnext1;
462 <a name="l00429"></a>00429
463 <a name="l00430"></a>00430 stageCnt--;
464 <a name="l00431"></a>00431
465 <a name="l00432"></a>00432 }
466 <a name="l00433"></a>00433
467 <a name="l00434"></a>00434 <span class="comment">/* y(n) = fN(n) */</span>
468 <a name="l00435"></a>00435 *pDst++ = __SSAT(fcurnt1, 16);
469 <a name="l00436"></a>00436
470 <a name="l00437"></a>00437
471 <a name="l00438"></a>00438 blkCnt--;
472 <a name="l00439"></a>00439
473 <a name="l00440"></a>00440 }
474 <a name="l00441"></a>00441
475 <a name="l00442"></a>00442 <span class="preprocessor">#else</span>
476 <a name="l00443"></a>00443 <span class="preprocessor"></span>
477 <a name="l00444"></a>00444 <span class="comment">/* Run the below code for Cortex-M0 */</span>
478 <a name="l00445"></a>00445
479 <a name="l00446"></a>00446 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> fcurnt, fnext, gcurnt, gnext; <span class="comment">/* temporary variables */</span>
480 <a name="l00447"></a>00447 uint32_t numStages = S-><a class="code" href="structarm__fir__lattice__instance__q15.html#a38b179138d6a6c9cac4f8f79b6fd5357">numStages</a>; <span class="comment">/* Length of the filter */</span>
481 <a name="l00448"></a>00448 uint32_t blkCnt, stageCnt; <span class="comment">/* temporary variables for counts */</span>
482 <a name="l00449"></a>00449
483 <a name="l00450"></a>00450 pState = &S-><a class="code" href="structarm__fir__lattice__instance__q15.html#a37b90dea2bc3ee7c9951a9fe74db0cbb">pState</a>[0];
484 <a name="l00451"></a>00451
485 <a name="l00452"></a>00452 blkCnt = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
486 <a name="l00453"></a>00453
487 <a name="l00454"></a>00454 <span class="keywordflow">while</span>(blkCnt > 0u)
488 <a name="l00455"></a>00455 {
489 <a name="l00456"></a>00456 <span class="comment">/* f0(n) = x(n) */</span>
490 <a name="l00457"></a>00457 fcurnt = *pSrc++;
491 <a name="l00458"></a>00458
492 <a name="l00459"></a>00459 <span class="comment">/* Initialize coeff pointer */</span>
493 <a name="l00460"></a>00460 pk = (pCoeffs);
494 <a name="l00461"></a>00461
495 <a name="l00462"></a>00462 <span class="comment">/* Initialize state pointer */</span>
496 <a name="l00463"></a>00463 px = pState;
497 <a name="l00464"></a>00464
498 <a name="l00465"></a>00465 <span class="comment">/* read g0(n-1) from state buffer */</span>
499 <a name="l00466"></a>00466 gcurnt = *px;
500 <a name="l00467"></a>00467
501 <a name="l00468"></a>00468 <span class="comment">/* for sample 1 processing */</span>
502 <a name="l00469"></a>00469 <span class="comment">/* f1(n) = f0(n) + K1 * g0(n-1) */</span>
503 <a name="l00470"></a>00470 fnext = ((gcurnt * (*pk)) >> 15u) + fcurnt;
504 <a name="l00471"></a>00471 fnext = __SSAT(fnext, 16);
505 <a name="l00472"></a>00472
506 <a name="l00473"></a>00473
507 <a name="l00474"></a>00474 <span class="comment">/* g1(n) = f0(n) * K1 + g0(n-1) */</span>
508 <a name="l00475"></a>00475 gnext = ((fcurnt * (*pk++)) >> 15u) + gcurnt;
509 <a name="l00476"></a>00476 gnext = __SSAT(gnext, 16);
510 <a name="l00477"></a>00477
511 <a name="l00478"></a>00478 <span class="comment">/* save f0(n) in state buffer */</span>
512 <a name="l00479"></a>00479 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) fcurnt;
513 <a name="l00480"></a>00480
514 <a name="l00481"></a>00481 <span class="comment">/* f1(n) is saved in fcurnt </span>
515 <a name="l00482"></a>00482 <span class="comment"> for next stage processing */</span>
516 <a name="l00483"></a>00483 fcurnt = fnext;
517 <a name="l00484"></a>00484
518 <a name="l00485"></a>00485 stageCnt = (numStages - 1u);
519 <a name="l00486"></a>00486
520 <a name="l00487"></a>00487 <span class="comment">/* stage loop */</span>
521 <a name="l00488"></a>00488 <span class="keywordflow">while</span>(stageCnt > 0u)
522 <a name="l00489"></a>00489 {
523 <a name="l00490"></a>00490 <span class="comment">/* read g1(n-1) from state buffer */</span>
524 <a name="l00491"></a>00491 gcurnt = *px;
525 <a name="l00492"></a>00492
526 <a name="l00493"></a>00493 <span class="comment">/* save g0(n-1) in state buffer */</span>
527 <a name="l00494"></a>00494 *px++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) gnext;
528 <a name="l00495"></a>00495
529 <a name="l00496"></a>00496 <span class="comment">/* Sample processing for K2, K3.... */</span>
530 <a name="l00497"></a>00497 <span class="comment">/* f2(n) = f1(n) + K2 * g1(n-1) */</span>
531 <a name="l00498"></a>00498 fnext = ((gcurnt * (*pk)) >> 15u) + fcurnt;
532 <a name="l00499"></a>00499 fnext = __SSAT(fnext, 16);
533 <a name="l00500"></a>00500
534 <a name="l00501"></a>00501 <span class="comment">/* g2(n) = f1(n) * K2 + g1(n-1) */</span>
535 <a name="l00502"></a>00502 gnext = ((fcurnt * (*pk++)) >> 15u) + gcurnt;
536 <a name="l00503"></a>00503 gnext = __SSAT(gnext, 16);
537 <a name="l00504"></a>00504
538 <a name="l00505"></a>00505
539 <a name="l00506"></a>00506 <span class="comment">/* f1(n) is saved in fcurnt </span>
540 <a name="l00507"></a>00507 <span class="comment"> for next stage processing */</span>
541 <a name="l00508"></a>00508 fcurnt = fnext;
542 <a name="l00509"></a>00509
543 <a name="l00510"></a>00510 stageCnt--;
544 <a name="l00511"></a>00511
545 <a name="l00512"></a>00512 }
546 <a name="l00513"></a>00513
547 <a name="l00514"></a>00514 <span class="comment">/* y(n) = fN(n) */</span>
548 <a name="l00515"></a>00515 *pDst++ = __SSAT(fcurnt, 16);
549 <a name="l00516"></a>00516
550 <a name="l00517"></a>00517
551 <a name="l00518"></a>00518 blkCnt--;
552 <a name="l00519"></a>00519
553 <a name="l00520"></a>00520 }
554 <a name="l00521"></a>00521
555 <a name="l00522"></a>00522 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
556 <a name="l00523"></a>00523
557 <a name="l00524"></a>00524 }
558 <a name="l00525"></a>00525
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