CMSIS DSP Software Library: arm_fir_sparse_q31.c Source File
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arm_fir_sparse_q31.c
Go to the documentation of this file.00001 /* ----------------------------------------------------------------------
00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
00003 *
00004 * $Date: 29. November 2010
00005 * $Revision: V1.0.3
00006 *
00007 * Project: CMSIS DSP Library
00008 * Title: arm_fir_sparse_q31.c
00009 *
00010 * Description: Q31 sparse FIR filter processing function.
00011 *
00012 * Target Processor: Cortex-M4/Cortex-M3
00013 *
00014 * Version 1.0.3 2010/11/29
00015 * Re-organized the CMSIS folders and updated documentation.
00016 *
00017 * Version 1.0.2 2010/11/11
00018 * Documentation updated.
00019 *
00020 * Version 1.0.1 2010/10/05
00021 * Production release and review comments incorporated.
00022 *
00023 * Version 1.0.0 2010/09/20
00024 * Production release and review comments incorporated
00025 *
00026 * Version 0.0.7 2010/06/10
00027 * Misra-C changes done
00028 * ------------------------------------------------------------------- */
00029 #include "arm_math.h"
00030
00031
00055 void arm_fir_sparse_q31(
00056 arm_fir_sparse_instance_q31 * S,
00057 q31_t * pSrc,
00058 q31_t * pDst,
00059 q31_t * pScratchIn,
00060 uint32_t blockSize)
00061 {
00062
00063 q31_t *pState = S->pState; /* State pointer */
00064 q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
00065 q31_t *px; /* Scratch buffer pointer */
00066 q31_t *py = pState; /* Temporary pointers for state buffer */
00067 q31_t *pb = pScratchIn; /* Temporary pointers for scratch buffer */
00068 q31_t *pOut; /* Destination pointer */
00069 q63_t out; /* Temporary output variable */
00070 int32_t *pTapDelay = S->pTapDelay; /* Pointer to the array containing offset of the non-zero tap values. */
00071 uint32_t delaySize = S->maxDelay + blockSize; /* state length */
00072 uint16_t numTaps = S->numTaps; /* Filter order */
00073 int32_t readIndex; /* Read index of the state buffer */
00074 uint32_t tapCnt, blkCnt; /* loop counters */
00075 q31_t coeff = *pCoeffs++; /* Read the first coefficient value */
00076 q31_t in;
00077
00078
00079 /* BlockSize of Input samples are copied into the state buffer */
00080 /* StateIndex points to the starting position to write in the state buffer */
00081 arm_circularWrite_f32((int32_t *) py, delaySize, &S->stateIndex, 1,
00082 (int32_t *) pSrc, 1, blockSize);
00083
00084 /* Read Index, from where the state buffer should be read, is calculated. */
00085 readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++;
00086
00087 /* Wraparound of readIndex */
00088 if(readIndex < 0)
00089 {
00090 readIndex += (int32_t) delaySize;
00091 }
00092
00093 /* Working pointer for state buffer is updated */
00094 py = pState;
00095
00096 /* blockSize samples are read from the state buffer */
00097 arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1,
00098 (int32_t *) pb, (int32_t *) pb, blockSize, 1,
00099 blockSize);
00100
00101 /* Working pointer for the scratch buffer of state values */
00102 px = pb;
00103
00104 /* Working pointer for scratch buffer of output values */
00105 pOut = pDst;
00106
00107 /* Loop over the blockSize. Unroll by a factor of 4.
00108 * Compute 4 Multiplications at a time. */
00109 blkCnt = blockSize >> 2;
00110
00111 while(blkCnt > 0u)
00112 {
00113 /* Perform Multiplications and store in the destination buffer */
00114 *pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32);
00115 *pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32);
00116 *pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32);
00117 *pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32);
00118
00119 /* Decrement the loop counter */
00120 blkCnt--;
00121 }
00122
00123 /* If the blockSize is not a multiple of 4,
00124 * compute the remaining samples */
00125 blkCnt = blockSize % 0x4u;
00126
00127 while(blkCnt > 0u)
00128 {
00129 /* Perform Multiplications and store in the destination buffer */
00130 *pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32);
00131
00132 /* Decrement the loop counter */
00133 blkCnt--;
00134 }
00135
00136 /* Load the coefficient value and
00137 * increment the coefficient buffer for the next set of state values */
00138 coeff = *pCoeffs++;
00139
00140 /* Read Index, from where the state buffer should be read, is calculated. */
00141 readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++;
00142
00143 /* Wraparound of readIndex */
00144 if(readIndex < 0)
00145 {
00146 readIndex += (int32_t) delaySize;
00147 }
00148
00149 /* Loop over the number of taps. */
00150 tapCnt = (uint32_t) numTaps - 1u;
00151
00152 while(tapCnt > 0u)
00153 {
00154 /* Working pointer for state buffer is updated */
00155 py = pState;
00156
00157 /* blockSize samples are read from the state buffer */
00158 arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1,
00159 (int32_t *) pb, (int32_t *) pb, blockSize, 1,
00160 blockSize);
00161
00162 /* Working pointer for the scratch buffer of state values */
00163 px = pb;
00164
00165 /* Working pointer for scratch buffer of output values */
00166 pOut = pDst;
00167
00168 /* Loop over the blockSize. Unroll by a factor of 4.
00169 * Compute 4 MACS at a time. */
00170 blkCnt = blockSize >> 2;
00171
00172 while(blkCnt > 0u)
00173 {
00174 out = *pOut;
00175 out += ((q63_t) * px++ * coeff) >> 32;
00176 *pOut++ = (q31_t) (out);
00177
00178 out = *pOut;
00179 out += ((q63_t) * px++ * coeff) >> 32;
00180 *pOut++ = (q31_t) (out);
00181
00182 out = *pOut;
00183 out += ((q63_t) * px++ * coeff) >> 32;
00184 *pOut++ = (q31_t) (out);
00185
00186 out = *pOut;
00187 out += ((q63_t) * px++ * coeff) >> 32;
00188 *pOut++ = (q31_t) (out);
00189
00190 /* Decrement the loop counter */
00191 blkCnt--;
00192 }
00193
00194 /* If the blockSize is not a multiple of 4,
00195 * compute the remaining samples */
00196 blkCnt = blockSize % 0x4u;
00197
00198 while(blkCnt > 0u)
00199 {
00200 /* Perform Multiply-Accumulate */
00201 out = *pOut;
00202 out += ((q63_t) * px++ * coeff) >> 32;
00203 *pOut++ = (q31_t) (out);
00204
00205 /* Decrement the loop counter */
00206 blkCnt--;
00207 }
00208
00209 /* Load the coefficient value and
00210 * increment the coefficient buffer for the next set of state values */
00211 coeff = *pCoeffs++;
00212
00213 /* Read Index, from where the state buffer should be read, is calculated. */
00214 readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++;
00215
00216 /* Wraparound of readIndex */
00217 if(readIndex < 0)
00218 {
00219 readIndex += (int32_t) delaySize;
00220 }
00221
00222 /* Decrement the tap loop counter */
00223 tapCnt--;
00224 }
00225
00226 /* Working output pointer is updated */
00227 pOut = pDst;
00228
00229 /* Output is converted into 1.15 format. */
00230 /* Loop over the blockSize. Unroll by a factor of 4.
00231 * process 4 output samples at a time. */
00232 blkCnt = blockSize >> 2;
00233
00234 while(blkCnt > 0u)
00235 {
00236 in = *pOut << 1;
00237 *pOut++ = in;
00238 in = *pOut << 1;
00239 *pOut++ = in;
00240 in = *pOut << 1;
00241 *pOut++ = in;
00242 in = *pOut << 1;
00243 *pOut++ = in;
00244
00245 /* Decrement the loop counter */
00246 blkCnt--;
00247 }
00248
00249 /* If the blockSize is not a multiple of 4,
00250 * process the remaining output samples */
00251 blkCnt = blockSize % 0x4u;
00252
00253 while(blkCnt > 0u)
00254 {
00255 in = *pOut << 1;
00256 *pOut++ = in;
00257
00258 /* Decrement the loop counter */
00259 blkCnt--;
00260 }
00261 }
00262
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