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45 <li><a href="globals.html"><span>Globals</span></a></li>
49 <div class="headertitle">
50 <h1>arm_biquad_cascade_df1_q15.c</h1> </div>
52 <div class="contents">
53 <a href="arm__biquad__cascade__df1__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_biquad_cascade_df1_q15.c </span>
61 <a name="l00009"></a>00009 <span class="comment">* </span>
62 <a name="l00010"></a>00010 <span class="comment">* Description: Processing function for the </span>
63 <a name="l00011"></a>00011 <span class="comment">* Q15 Biquad cascade DirectFormI(DF1) filter. </span>
64 <a name="l00012"></a>00012 <span class="comment">* </span>
65 <a name="l00013"></a>00013 <span class="comment">* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0</span>
66 <a name="l00014"></a>00014 <span class="comment">* </span>
67 <a name="l00015"></a>00015 <span class="comment">* Version 1.0.10 2011/7/15 </span>
68 <a name="l00016"></a>00016 <span class="comment">* Big Endian support added and Merged M0 and M3/M4 Source code. </span>
69 <a name="l00017"></a>00017 <span class="comment">* </span>
70 <a name="l00018"></a>00018 <span class="comment">* Version 1.0.3 2010/11/29 </span>
71 <a name="l00019"></a>00019 <span class="comment">* Re-organized the CMSIS folders and updated documentation. </span>
72 <a name="l00020"></a>00020 <span class="comment">* </span>
73 <a name="l00021"></a>00021 <span class="comment">* Version 1.0.2 2010/11/11 </span>
74 <a name="l00022"></a>00022 <span class="comment">* Documentation updated. </span>
75 <a name="l00023"></a>00023 <span class="comment">* </span>
76 <a name="l00024"></a>00024 <span class="comment">* Version 1.0.1 2010/10/05 </span>
77 <a name="l00025"></a>00025 <span class="comment">* Production release and review comments incorporated. </span>
78 <a name="l00026"></a>00026 <span class="comment">* </span>
79 <a name="l00027"></a>00027 <span class="comment">* Version 1.0.0 2010/09/20 </span>
80 <a name="l00028"></a>00028 <span class="comment">* Production release and review comments incorporated. </span>
81 <a name="l00029"></a>00029 <span class="comment">* </span>
82 <a name="l00030"></a>00030 <span class="comment">* Version 0.0.5 2010/04/26 </span>
83 <a name="l00031"></a>00031 <span class="comment">* incorporated review comments and updated with latest CMSIS layer </span>
84 <a name="l00032"></a>00032 <span class="comment">* </span>
85 <a name="l00033"></a>00033 <span class="comment">* Version 0.0.3 2010/03/10 </span>
86 <a name="l00034"></a>00034 <span class="comment">* Initial version </span>
87 <a name="l00035"></a>00035 <span class="comment">* -------------------------------------------------------------------- */</span>
88 <a name="l00036"></a>00036
89 <a name="l00037"></a>00037 <span class="preprocessor">#include "<a class="code" href="arm__math_8h.html">arm_math.h</a>"</span>
90 <a name="l00038"></a>00038
91 <a name="l00070"></a><a class="code" href="group___biquad_cascade_d_f1.html#gadd66a0aefdc645031d607b0a5b37a942">00070</a> <span class="keywordtype">void</span> <a class="code" href="group___biquad_cascade_d_f1.html#gadd66a0aefdc645031d607b0a5b37a942" title="Processing function for the Q15 Biquad cascade filter.">arm_biquad_cascade_df1_q15</a>(
92 <a name="l00071"></a>00071 <span class="keyword">const</span> <a class="code" href="structarm__biquad__casd__df1__inst__q15.html" title="Instance structure for the Q15 Biquad cascade filter.">arm_biquad_casd_df1_inst_q15</a> * S,
93 <a name="l00072"></a>00072 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> * pSrc,
94 <a name="l00073"></a>00073 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> * pDst,
95 <a name="l00074"></a>00074 uint32_t <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>)
96 <a name="l00075"></a>00075 {
97 <a name="l00076"></a>00076
98 <a name="l00077"></a>00077
99 <a name="l00078"></a>00078 <span class="preprocessor">#ifndef ARM_MATH_CM0</span>
100 <a name="l00079"></a>00079 <span class="preprocessor"></span>
101 <a name="l00080"></a>00080 <span class="comment">/* Run the below code for Cortex-M4 and Cortex-M3 */</span>
102 <a name="l00081"></a>00081
103 <a name="l00082"></a>00082 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pIn = pSrc; <span class="comment">/* Source pointer */</span>
104 <a name="l00083"></a>00083 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pOut = pDst; <span class="comment">/* Destination pointer */</span>
105 <a name="l00084"></a>00084 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> in; <span class="comment">/* Temporary variable to hold input value */</span>
106 <a name="l00085"></a>00085 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> out; <span class="comment">/* Temporary variable to hold output value */</span>
107 <a name="l00086"></a>00086 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> b0; <span class="comment">/* Temporary variable to hold bo value */</span>
108 <a name="l00087"></a>00087 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> b1, a1; <span class="comment">/* Filter coefficients */</span>
109 <a name="l00088"></a>00088 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> state_in, state_out; <span class="comment">/* Filter state variables */</span>
110 <a name="l00089"></a>00089 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> acc; <span class="comment">/* Accumulator */</span>
111 <a name="l00090"></a>00090 int32_t shift = (15 - (int32_t) S-><a class="code" href="structarm__biquad__casd__df1__inst__q15.html#ada7e9d6269e6ed4eacf8f68729e9832d">postShift</a>); <span class="comment">/* Post shift */</span>
112 <a name="l00091"></a>00091 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pState = S-><a class="code" href="structarm__biquad__casd__df1__inst__q15.html#a5481104ef2f8f81360b80b47d69ae932">pState</a>; <span class="comment">/* State pointer */</span>
113 <a name="l00092"></a>00092 <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__biquad__casd__df1__inst__q15.html#a1edaacdebb5b09d7635bf20c779855fc">pCoeffs</a>; <span class="comment">/* Coefficient pointer */</span>
114 <a name="l00093"></a>00093 <a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *pState_q31; <span class="comment">/* 32-bit state pointer for SIMD implementation */</span>
115 <a name="l00094"></a>00094 uint32_t sample, stage = (uint32_t) S-><a class="code" href="structarm__biquad__casd__df1__inst__q15.html#ad6d95e70abcf4ff1300181415ad92153">numStages</a>; <span class="comment">/* Stage loop counter */</span>
116 <a name="l00095"></a>00095
117 <a name="l00096"></a>00096 <span class="keywordflow">do</span>
118 <a name="l00097"></a>00097 {
119 <a name="l00098"></a>00098 <span class="comment">/* Initialize state pointer of type q31 */</span>
120 <a name="l00099"></a>00099 pState_q31 = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a> *) (pState);
121 <a name="l00100"></a>00100
122 <a name="l00101"></a>00101 <span class="comment">/* Read the b0 and 0 coefficients using SIMD */</span>
123 <a name="l00102"></a>00102 b0 = *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pCoeffs)++;
124 <a name="l00103"></a>00103
125 <a name="l00104"></a>00104 <span class="comment">/* Read the b1 and b2 coefficients using SIMD */</span>
126 <a name="l00105"></a>00105 b1 = *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pCoeffs)++;
127 <a name="l00106"></a>00106
128 <a name="l00107"></a>00107 <span class="comment">/* Read the a1 and a2 coefficients using SIMD */</span>
129 <a name="l00108"></a>00108 a1 = *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pCoeffs)++;
130 <a name="l00109"></a>00109
131 <a name="l00110"></a>00110 <span class="comment">/* Read the input state values from the state buffer: x[n-1], x[n-2] */</span>
132 <a name="l00111"></a>00111 state_in = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (*pState_q31++);
133 <a name="l00112"></a>00112
134 <a name="l00113"></a>00113 <span class="comment">/* Read the output state values from the state buffer: y[n-1], y[n-2] */</span>
135 <a name="l00114"></a>00114 state_out = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) (*pState_q31);
136 <a name="l00115"></a>00115
137 <a name="l00116"></a>00116 <span class="comment">/* Apply loop unrolling and compute 2 output values simultaneously. */</span>
138 <a name="l00117"></a>00117 <span class="comment">/* The variable acc hold output values that are being computed: </span>
139 <a name="l00118"></a>00118 <span class="comment"> * </span>
140 <a name="l00119"></a>00119 <span class="comment"> * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] </span>
141 <a name="l00120"></a>00120 <span class="comment"> * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] </span>
142 <a name="l00121"></a>00121 <span class="comment"> */</span>
143 <a name="l00122"></a>00122 sample = blockSize >> 1u;
144 <a name="l00123"></a>00123
145 <a name="l00124"></a>00124 <span class="comment">/* First part of the processing with loop unrolling. Compute 2 outputs at a time. </span>
146 <a name="l00125"></a>00125 <span class="comment"> ** a second loop below computes the remaining 1 sample. */</span>
147 <a name="l00126"></a>00126 <span class="keywordflow">while</span>(sample > 0u)
148 <a name="l00127"></a>00127 {
149 <a name="l00128"></a>00128
150 <a name="l00129"></a>00129 <span class="comment">/* Read the input */</span>
151 <a name="l00130"></a>00130 in = *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pIn)++;
152 <a name="l00131"></a>00131
153 <a name="l00132"></a>00132 <span class="comment">/* out = b0 * x[n] + 0 * 0 */</span>
154 <a name="l00133"></a>00133 out = __SMUAD(b0, in);
155 <a name="l00134"></a>00134
156 <a name="l00135"></a>00135 <span class="comment">/* acc += b1 * x[n-1] + b2 * x[n-2] + out */</span>
157 <a name="l00136"></a>00136 acc = __SMLALD(b1, state_in, out);
158 <a name="l00137"></a>00137 <span class="comment">/* acc += a1 * y[n-1] + a2 * y[n-2] */</span>
159 <a name="l00138"></a>00138 acc = __SMLALD(a1, state_out, acc);
160 <a name="l00139"></a>00139
161 <a name="l00140"></a>00140 <span class="comment">/* The result is converted from 3.29 to 1.31 if postShift = 1, and then saturation is applied */</span>
162 <a name="l00141"></a>00141 out = __SSAT((acc >> shift), 16);
163 <a name="l00142"></a>00142
164 <a name="l00143"></a>00143 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
165 <a name="l00144"></a>00144 <span class="comment">/* The states should be updated as: */</span>
166 <a name="l00145"></a>00145 <span class="comment">/* Xn2 = Xn1 */</span>
167 <a name="l00146"></a>00146 <span class="comment">/* Xn1 = Xn */</span>
168 <a name="l00147"></a>00147 <span class="comment">/* Yn2 = Yn1 */</span>
169 <a name="l00148"></a>00148 <span class="comment">/* Yn1 = acc */</span>
170 <a name="l00149"></a>00149 <span class="comment">/* x[n-N], x[n-N-1] are packed together to make state_in of type q31 */</span>
171 <a name="l00150"></a>00150 <span class="comment">/* y[n-N], y[n-N-1] are packed together to make state_out of type q31 */</span>
172 <a name="l00151"></a>00151
173 <a name="l00152"></a>00152 <span class="preprocessor">#ifndef ARM_MATH_BIG_ENDIAN</span>
174 <a name="l00153"></a>00153 <span class="preprocessor"></span>
175 <a name="l00154"></a>00154 state_in = __PKHBT(in, state_in, 16);
176 <a name="l00155"></a>00155 state_out = __PKHBT(out, state_out, 16);
177 <a name="l00156"></a>00156
178 <a name="l00157"></a>00157 <span class="preprocessor">#else</span>
179 <a name="l00158"></a>00158 <span class="preprocessor"></span>
180 <a name="l00159"></a>00159 state_in = __PKHBT(state_in >> 16, (in >> 16), 16);
181 <a name="l00160"></a>00160 state_out = __PKHBT(state_out >> 16, (out), 16);
182 <a name="l00161"></a>00161
183 <a name="l00162"></a>00162 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_BIG_ENDIAN */</span>
184 <a name="l00163"></a>00163
185 <a name="l00164"></a>00164 <span class="comment">/* out = b0 * x[n] + 0 * 0 */</span>
186 <a name="l00165"></a>00165 out = __SMUADX(b0, in);
187 <a name="l00166"></a>00166 <span class="comment">/* acc += b1 * x[n-1] + b2 * x[n-2] + out */</span>
188 <a name="l00167"></a>00167 acc = __SMLALD(b1, state_in, out);
189 <a name="l00168"></a>00168 <span class="comment">/* acc += a1 * y[n-1] + a2 * y[n-2] */</span>
190 <a name="l00169"></a>00169 acc = __SMLALD(a1, state_out, acc);
191 <a name="l00170"></a>00170
192 <a name="l00171"></a>00171 <span class="comment">/* The result is converted from 3.29 to 1.31 if postShift = 1, and then saturation is applied */</span>
193 <a name="l00172"></a>00172 out = __SSAT((acc >> shift), 16);
194 <a name="l00173"></a>00173
195 <a name="l00174"></a>00174 <span class="comment">/* Store the output in the destination buffer. */</span>
196 <a name="l00175"></a>00175
197 <a name="l00176"></a>00176 <span class="preprocessor">#ifndef ARM_MATH_BIG_ENDIAN</span>
198 <a name="l00177"></a>00177 <span class="preprocessor"></span>
199 <a name="l00178"></a>00178 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pOut)++ = __PKHBT(state_out, out, 16);
200 <a name="l00179"></a>00179
201 <a name="l00180"></a>00180 <span class="preprocessor">#else</span>
202 <a name="l00181"></a>00181 <span class="preprocessor"></span>
203 <a name="l00182"></a>00182 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pOut)++ = __PKHBT(out, state_out >> 16, 16);
204 <a name="l00183"></a>00183
205 <a name="l00184"></a>00184 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_BIG_ENDIAN */</span>
206 <a name="l00185"></a>00185
207 <a name="l00186"></a>00186 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
208 <a name="l00187"></a>00187 <span class="comment">/* The states should be updated as: */</span>
209 <a name="l00188"></a>00188 <span class="comment">/* Xn2 = Xn1 */</span>
210 <a name="l00189"></a>00189 <span class="comment">/* Xn1 = Xn */</span>
211 <a name="l00190"></a>00190 <span class="comment">/* Yn2 = Yn1 */</span>
212 <a name="l00191"></a>00191 <span class="comment">/* Yn1 = acc */</span>
213 <a name="l00192"></a>00192 <span class="comment">/* x[n-N], x[n-N-1] are packed together to make state_in of type q31 */</span>
214 <a name="l00193"></a>00193 <span class="comment">/* y[n-N], y[n-N-1] are packed together to make state_out of type q31 */</span>
215 <a name="l00194"></a>00194 <span class="preprocessor">#ifndef ARM_MATH_BIG_ENDIAN</span>
216 <a name="l00195"></a>00195 <span class="preprocessor"></span>
217 <a name="l00196"></a>00196 state_in = __PKHBT(in >> 16, state_in, 16);
218 <a name="l00197"></a>00197 state_out = __PKHBT(out, state_out, 16);
219 <a name="l00198"></a>00198
220 <a name="l00199"></a>00199 <span class="preprocessor">#else</span>
221 <a name="l00200"></a>00200 <span class="preprocessor"></span>
222 <a name="l00201"></a>00201 state_in = __PKHBT(state_in >> 16, in, 16);
223 <a name="l00202"></a>00202 state_out = __PKHBT(state_out >> 16, out, 16);
224 <a name="l00203"></a>00203
225 <a name="l00204"></a>00204 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_BIG_ENDIAN */</span>
226 <a name="l00205"></a>00205
227 <a name="l00206"></a>00206
228 <a name="l00207"></a>00207 <span class="comment">/* Decrement the loop counter */</span>
229 <a name="l00208"></a>00208 sample--;
230 <a name="l00209"></a>00209
231 <a name="l00210"></a>00210 }
232 <a name="l00211"></a>00211
233 <a name="l00212"></a>00212 <span class="comment">/* If the blockSize is not a multiple of 2, compute any remaining output samples here. </span>
234 <a name="l00213"></a>00213 <span class="comment"> ** No loop unrolling is used. */</span>
235 <a name="l00214"></a>00214
236 <a name="l00215"></a>00215 <span class="keywordflow">if</span>((blockSize & 0x1u) != 0u)
237 <a name="l00216"></a>00216 {
238 <a name="l00217"></a>00217 <span class="comment">/* Read the input */</span>
239 <a name="l00218"></a>00218 in = *pIn++;
240 <a name="l00219"></a>00219
241 <a name="l00220"></a>00220 <span class="comment">/* out = b0 * x[n] + 0 * 0 */</span>
242 <a name="l00221"></a>00221
243 <a name="l00222"></a>00222 <span class="preprocessor">#ifndef ARM_MATH_BIG_ENDIAN</span>
244 <a name="l00223"></a>00223 <span class="preprocessor"></span>
245 <a name="l00224"></a>00224 out = __SMUAD(b0, in);
246 <a name="l00225"></a>00225
247 <a name="l00226"></a>00226 <span class="preprocessor">#else</span>
248 <a name="l00227"></a>00227 <span class="preprocessor"></span>
249 <a name="l00228"></a>00228 out = __SMUADX(b0, in);
250 <a name="l00229"></a>00229
251 <a name="l00230"></a>00230 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_BIG_ENDIAN */</span>
252 <a name="l00231"></a>00231
253 <a name="l00232"></a>00232 <span class="comment">/* acc = b1 * x[n-1] + b2 * x[n-2] + out */</span>
254 <a name="l00233"></a>00233 acc = __SMLALD(b1, state_in, out);
255 <a name="l00234"></a>00234 <span class="comment">/* acc += a1 * y[n-1] + a2 * y[n-2] */</span>
256 <a name="l00235"></a>00235 acc = __SMLALD(a1, state_out, acc);
257 <a name="l00236"></a>00236
258 <a name="l00237"></a>00237 <span class="comment">/* The result is converted from 3.29 to 1.31 if postShift = 1, and then saturation is applied */</span>
259 <a name="l00238"></a>00238 out = __SSAT((acc >> shift), 16);
260 <a name="l00239"></a>00239
261 <a name="l00240"></a>00240 <span class="comment">/* Store the output in the destination buffer. */</span>
262 <a name="l00241"></a>00241 *pOut++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) out;
263 <a name="l00242"></a>00242
264 <a name="l00243"></a>00243 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
265 <a name="l00244"></a>00244 <span class="comment">/* The states should be updated as: */</span>
266 <a name="l00245"></a>00245 <span class="comment">/* Xn2 = Xn1 */</span>
267 <a name="l00246"></a>00246 <span class="comment">/* Xn1 = Xn */</span>
268 <a name="l00247"></a>00247 <span class="comment">/* Yn2 = Yn1 */</span>
269 <a name="l00248"></a>00248 <span class="comment">/* Yn1 = acc */</span>
270 <a name="l00249"></a>00249 <span class="comment">/* x[n-N], x[n-N-1] are packed together to make state_in of type q31 */</span>
271 <a name="l00250"></a>00250 <span class="comment">/* y[n-N], y[n-N-1] are packed together to make state_out of type q31 */</span>
272 <a name="l00251"></a>00251
273 <a name="l00252"></a>00252 <span class="preprocessor">#ifndef ARM_MATH_BIG_ENDIAN</span>
274 <a name="l00253"></a>00253 <span class="preprocessor"></span>
275 <a name="l00254"></a>00254 state_in = __PKHBT(in, state_in, 16);
276 <a name="l00255"></a>00255 state_out = __PKHBT(out, state_out, 16);
277 <a name="l00256"></a>00256
278 <a name="l00257"></a>00257 <span class="preprocessor">#else</span>
279 <a name="l00258"></a>00258 <span class="preprocessor"></span>
280 <a name="l00259"></a>00259 state_in = __PKHBT(state_in >> 16, in, 16);
281 <a name="l00260"></a>00260 state_out = __PKHBT(state_out >> 16, out, 16);
282 <a name="l00261"></a>00261
283 <a name="l00262"></a>00262 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_BIG_ENDIAN */</span>
284 <a name="l00263"></a>00263
285 <a name="l00264"></a>00264 }
286 <a name="l00265"></a>00265
287 <a name="l00266"></a>00266 <span class="comment">/* The first stage goes from the input wire to the output wire. */</span>
288 <a name="l00267"></a>00267 <span class="comment">/* Subsequent numStages occur in-place in the output wire */</span>
289 <a name="l00268"></a>00268 pIn = pDst;
290 <a name="l00269"></a>00269
291 <a name="l00270"></a>00270 <span class="comment">/* Reset the output pointer */</span>
292 <a name="l00271"></a>00271 pOut = pDst;
293 <a name="l00272"></a>00272
294 <a name="l00273"></a>00273 <span class="comment">/* Store the updated state variables back into the state array */</span>
295 <a name="l00274"></a>00274 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pState)++ = state_in;
296 <a name="l00275"></a>00275 *<a class="code" href="arm__math_8h.html#a9de2e0a5785be82866bcb96012282248" title="definition to read/write two 16 bit values.">__SIMD32</a>(pState)++ = state_out;
297 <a name="l00276"></a>00276
298 <a name="l00277"></a>00277
299 <a name="l00278"></a>00278 <span class="comment">/* Decrement the loop counter */</span>
300 <a name="l00279"></a>00279 stage--;
301 <a name="l00280"></a>00280
302 <a name="l00281"></a>00281 } <span class="keywordflow">while</span>(stage > 0u);
303 <a name="l00282"></a>00282
304 <a name="l00283"></a>00283 <span class="preprocessor">#else</span>
305 <a name="l00284"></a>00284 <span class="preprocessor"></span>
306 <a name="l00285"></a>00285 <span class="comment">/* Run the below code for Cortex-M0 */</span>
307 <a name="l00286"></a>00286
308 <a name="l00287"></a>00287 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pIn = pSrc; <span class="comment">/* Source pointer */</span>
309 <a name="l00288"></a>00288 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pOut = pDst; <span class="comment">/* Destination pointer */</span>
310 <a name="l00289"></a>00289 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> b0, b1, b2, a1, a2; <span class="comment">/* Filter coefficients */</span>
311 <a name="l00290"></a>00290 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> Xn1, Xn2, Yn1, Yn2; <span class="comment">/* Filter state variables */</span>
312 <a name="l00291"></a>00291 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> Xn; <span class="comment">/* temporary input */</span>
313 <a name="l00292"></a>00292 <a class="code" href="arm__math_8h.html#a5aea1cb12fc02d9d44c8abf217eaa5c6" title="64-bit fractional data type in 1.63 format.">q63_t</a> acc; <span class="comment">/* Accumulator */</span>
314 <a name="l00293"></a>00293 int32_t shift = (15 - (int32_t) S->postShift); <span class="comment">/* Post shift */</span>
315 <a name="l00294"></a>00294 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pState = S->pState; <span class="comment">/* State pointer */</span>
316 <a name="l00295"></a>00295 <a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a> *pCoeffs = S->pCoeffs; <span class="comment">/* Coefficient pointer */</span>
317 <a name="l00296"></a>00296 uint32_t sample, stage = (uint32_t) S->numStages; <span class="comment">/* Stage loop counter */</span>
318 <a name="l00297"></a>00297
319 <a name="l00298"></a>00298 <span class="keywordflow">do</span>
320 <a name="l00299"></a>00299 {
321 <a name="l00300"></a>00300 <span class="comment">/* Reading the coefficients */</span>
322 <a name="l00301"></a>00301 b0 = *pCoeffs++;
323 <a name="l00302"></a>00302 b1 = *pCoeffs++;
324 <a name="l00303"></a>00303 b2 = *pCoeffs++;
325 <a name="l00304"></a>00304 a1 = *pCoeffs++;
326 <a name="l00305"></a>00305 a2 = *pCoeffs++;
327 <a name="l00306"></a>00306
328 <a name="l00307"></a>00307 <span class="comment">/* Reading the state values */</span>
329 <a name="l00308"></a>00308 Xn1 = pState[0];
330 <a name="l00309"></a>00309 Xn2 = pState[1];
331 <a name="l00310"></a>00310 Yn1 = pState[2];
332 <a name="l00311"></a>00311 Yn2 = pState[3];
333 <a name="l00312"></a>00312
334 <a name="l00313"></a>00313 <span class="comment">/* The variables acc holds the output value that is computed: </span>
335 <a name="l00314"></a>00314 <span class="comment"> * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] </span>
336 <a name="l00315"></a>00315 <span class="comment"> */</span>
337 <a name="l00316"></a>00316
338 <a name="l00317"></a>00317 sample = <a class="code" href="arm__fir__example__f32_8c.html#ab6558f40a619c2502fbc24c880fd4fb0">blockSize</a>;
339 <a name="l00318"></a>00318
340 <a name="l00319"></a>00319 <span class="keywordflow">while</span>(sample > 0u)
341 <a name="l00320"></a>00320 {
342 <a name="l00321"></a>00321 <span class="comment">/* Read the input */</span>
343 <a name="l00322"></a>00322 Xn = *pIn++;
344 <a name="l00323"></a>00323
345 <a name="l00324"></a>00324 <span class="comment">/* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */</span>
346 <a name="l00325"></a>00325 <span class="comment">/* acc = b0 * x[n] */</span>
347 <a name="l00326"></a>00326 acc = (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) b0 *Xn;
348 <a name="l00327"></a>00327
349 <a name="l00328"></a>00328 <span class="comment">/* acc += b1 * x[n-1] */</span>
350 <a name="l00329"></a>00329 acc += (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) b1 *Xn1;
351 <a name="l00330"></a>00330 <span class="comment">/* acc += b[2] * x[n-2] */</span>
352 <a name="l00331"></a>00331 acc += (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) b2 *Xn2;
353 <a name="l00332"></a>00332 <span class="comment">/* acc += a1 * y[n-1] */</span>
354 <a name="l00333"></a>00333 acc += (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) a1 *Yn1;
355 <a name="l00334"></a>00334 <span class="comment">/* acc += a2 * y[n-2] */</span>
356 <a name="l00335"></a>00335 acc += (<a class="code" href="arm__math_8h.html#adc89a3547f5324b7b3b95adec3806bc0" title="32-bit fractional data type in 1.31 format.">q31_t</a>) a2 *Yn2;
357 <a name="l00336"></a>00336
358 <a name="l00337"></a>00337 <span class="comment">/* The result is converted to 1.31 */</span>
359 <a name="l00338"></a>00338 acc = __SSAT((acc >> shift), 16);
360 <a name="l00339"></a>00339
361 <a name="l00340"></a>00340 <span class="comment">/* Every time after the output is computed state should be updated. */</span>
362 <a name="l00341"></a>00341 <span class="comment">/* The states should be updated as: */</span>
363 <a name="l00342"></a>00342 <span class="comment">/* Xn2 = Xn1 */</span>
364 <a name="l00343"></a>00343 <span class="comment">/* Xn1 = Xn */</span>
365 <a name="l00344"></a>00344 <span class="comment">/* Yn2 = Yn1 */</span>
366 <a name="l00345"></a>00345 <span class="comment">/* Yn1 = acc */</span>
367 <a name="l00346"></a>00346 Xn2 = Xn1;
368 <a name="l00347"></a>00347 Xn1 = Xn;
369 <a name="l00348"></a>00348 Yn2 = Yn1;
370 <a name="l00349"></a>00349 Yn1 = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) acc;
371 <a name="l00350"></a>00350
372 <a name="l00351"></a>00351 <span class="comment">/* Store the output in the destination buffer. */</span>
373 <a name="l00352"></a>00352 *pOut++ = (<a class="code" href="arm__math_8h.html#ab5a8fb21a5b3b983d5f54f31614052ea" title="16-bit fractional data type in 1.15 format.">q15_t</a>) acc;
374 <a name="l00353"></a>00353
375 <a name="l00354"></a>00354 <span class="comment">/* decrement the loop counter */</span>
376 <a name="l00355"></a>00355 sample--;
377 <a name="l00356"></a>00356 }
378 <a name="l00357"></a>00357
379 <a name="l00358"></a>00358 <span class="comment">/* The first stage goes from the input buffer to the output buffer. */</span>
380 <a name="l00359"></a>00359 <span class="comment">/* Subsequent stages occur in-place in the output buffer */</span>
381 <a name="l00360"></a>00360 pIn = pDst;
382 <a name="l00361"></a>00361
383 <a name="l00362"></a>00362 <span class="comment">/* Reset to destination pointer */</span>
384 <a name="l00363"></a>00363 pOut = pDst;
385 <a name="l00364"></a>00364
386 <a name="l00365"></a>00365 <span class="comment">/* Store the updated state variables back into the pState array */</span>
387 <a name="l00366"></a>00366 *pState++ = Xn1;
388 <a name="l00367"></a>00367 *pState++ = Xn2;
389 <a name="l00368"></a>00368 *pState++ = Yn1;
390 <a name="l00369"></a>00369 *pState++ = Yn2;
391 <a name="l00370"></a>00370
392 <a name="l00371"></a>00371 } <span class="keywordflow">while</span>(--stage);
393 <a name="l00372"></a>00372
394 <a name="l00373"></a>00373 <span class="preprocessor">#endif </span><span class="comment">/* #ifndef ARM_MATH_CM0 */</span>
395 <a name="l00374"></a>00374
396 <a name="l00375"></a>00375 }
397 <a name="l00376"></a>00376
398 <a name="l00377"></a>00377
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