CMSIS DSP Software Library: arm_fir_interpolate_f32.c Source File
Main Page
Modules
Data Structures
Files
Examples
File List
Globals
arm_fir_interpolate_f32.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_interpolate_f32.c
00009 *
00010 * Description: FIR interpolation for floating-point sequences.
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
00030 #include "arm_math.h"
00031
00132 void arm_fir_interpolate_f32(
00133 const arm_fir_interpolate_instance_f32 * S,
00134 float32_t * pSrc,
00135 float32_t * pDst,
00136 uint32_t blockSize)
00137 {
00138 float32_t *pState = S->pState; /* State pointer */
00139 float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
00140 float32_t *pStateCurnt; /* Points to the current sample of the state */
00141 float32_t *ptr1, *ptr2; /* Temporary pointers for state and coefficient buffers */
00142 float32_t sum0; /* Accumulators */
00143 float32_t x0, c0; /* Temporary variables to hold state and coefficient values */
00144 uint32_t i, blkCnt, j; /* Loop counters */
00145 uint16_t phaseLen = S->phaseLength, tapCnt; /* Length of each polyphase filter component */
00146
00147
00148 /* S->pState buffer contains previous frame (phaseLen - 1) samples */
00149 /* pStateCurnt points to the location where the new input data should be written */
00150 pStateCurnt = S->pState + (phaseLen - 1u);
00151
00152 /* Total number of intput samples */
00153 blkCnt = blockSize;
00154
00155 /* Loop over the blockSize. */
00156 while(blkCnt > 0u)
00157 {
00158 /* Copy new input sample into the state buffer */
00159 *pStateCurnt++ = *pSrc++;
00160
00161 /* Address modifier index of coefficient buffer */
00162 j = 1u;
00163
00164 /* Loop over the Interpolation factor. */
00165 i = S->L;
00166 while(i > 0u)
00167 {
00168 /* Set accumulator to zero */
00169 sum0 = 0.0f;
00170
00171 /* Initialize state pointer */
00172 ptr1 = pState;
00173
00174 /* Initialize coefficient pointer */
00175 ptr2 = pCoeffs + (S->L - j);
00176
00177 /* Loop over the polyPhase length. Unroll by a factor of 4.
00178 ** Repeat until we've computed numTaps-(4*S->L) coefficients. */
00179 tapCnt = phaseLen >> 2u;
00180 while(tapCnt > 0u)
00181 {
00182
00183 /* Read the coefficient */
00184 c0 = *(ptr2);
00185
00186 /* Upsampling is done by stuffing L-1 zeros between each sample.
00187 * So instead of multiplying zeros with coefficients,
00188 * Increment the coefficient pointer by interpolation factor times. */
00189 ptr2 += S->L;
00190
00191 /* Read the input sample */
00192 x0 = *(ptr1++);
00193
00194 /* Perform the multiply-accumulate */
00195 sum0 += x0 * c0;
00196
00197 /* Read the coefficient */
00198 c0 = *(ptr2);
00199
00200 /* Increment the coefficient pointer by interpolation factor times. */
00201 ptr2 += S->L;
00202
00203 /* Read the input sample */
00204 x0 = *(ptr1++);
00205
00206 /* Perform the multiply-accumulate */
00207 sum0 += x0 * c0;
00208
00209 /* Read the coefficient */
00210 c0 = *(ptr2);
00211
00212 /* Increment the coefficient pointer by interpolation factor times. */
00213 ptr2 += S->L;
00214
00215 /* Read the input sample */
00216 x0 = *(ptr1++);
00217
00218 /* Perform the multiply-accumulate */
00219 sum0 += x0 * c0;
00220
00221 /* Read the coefficient */
00222 c0 = *(ptr2);
00223
00224 /* Increment the coefficient pointer by interpolation factor times. */
00225 ptr2 += S->L;
00226
00227 /* Read the input sample */
00228 x0 = *(ptr1++);
00229
00230 /* Perform the multiply-accumulate */
00231 sum0 += x0 * c0;
00232
00233 /* Decrement the loop counter */
00234 tapCnt--;
00235 }
00236
00237 /* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */
00238 tapCnt = phaseLen % 0x4u;
00239
00240 while(tapCnt > 0u)
00241 {
00242 /* Perform the multiply-accumulate */
00243 sum0 += *(ptr1++) * (*ptr2);
00244
00245 /* Increment the coefficient pointer by interpolation factor times. */
00246 ptr2 += S->L;
00247
00248 /* Decrement the loop counter */
00249 tapCnt--;
00250 }
00251
00252 /* The result is in the accumulator, store in the destination buffer. */
00253 *pDst++ = sum0;
00254
00255 /* Increment the address modifier index of coefficient buffer */
00256 j++;
00257
00258 /* Decrement the loop counter */
00259 i--;
00260 }
00261
00262 /* Advance the state pointer by 1
00263 * to process the next group of interpolation factor number samples */
00264 pState = pState + 1;
00265
00266 /* Decrement the loop counter */
00267 blkCnt--;
00268 }
00269
00270 /* Processing is complete.
00271 ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer.
00272 ** This prepares the state buffer for the next function call. */
00273
00274 /* Points to the start of the state buffer */
00275 pStateCurnt = S->pState;
00276
00277 tapCnt = (phaseLen - 1u) >> 2u;
00278
00279 /* copy data */
00280 while(tapCnt > 0u)
00281 {
00282 *pStateCurnt++ = *pState++;
00283 *pStateCurnt++ = *pState++;
00284 *pStateCurnt++ = *pState++;
00285 *pStateCurnt++ = *pState++;
00286
00287 /* Decrement the loop counter */
00288 tapCnt--;
00289 }
00290
00291 tapCnt = (phaseLen - 1u) % 0x04u;
00292
00293 while(tapCnt > 0u)
00294 {
00295 *pStateCurnt++ = *pState++;
00296
00297 /* Decrement the loop counter */
00298 tapCnt--;
00299 }
00300 }
00301
All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Defines
Generated on Mon Nov 29 2010 17:19:56 for CMSIS DSP Software Library by
1.7.2
Wyszukiwarka
Podobne podstrony:
arm fir interpolate q31? sourcearm fir lattice ?2? sourcearm fir init ?2? sourcearm fir example ?2? sourcearm fir sparse ?2? sourcearm fir ?cimate ?2? sourcearm fir interpolate q15? sourcearm fir interpolate ?2?arm fir interpolate init ?2? sourcearm fir interpolate init q15? sourcearm fir interpolate init q31? sourcearm fir interpolate init q31? sourcearm fir interpolate init ?2?arm fir ?cimate ?2?arm fir init q15? sourcearm cmplx mag ?2? sourcearm fir ?cimate q31? sourcearm mat trans ?2? sourcearm fir sparse ?2?więcej podobnych podstron