arm_fir_lattice_q15.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        19. March 2015
00005 * $Revision:    V.1.4.5
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_fir_lattice_q15.c    
00009 *    
00010 * Description:  Q15 FIR lattice filter processing function.    
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE. 
00039 * -------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 
00043 /**    
00044  * @ingroup groupFilters    
00045  */
00046 
00047 /**    
00048  * @addtogroup FIR_Lattice    
00049  * @{    
00050  */
00051 
00052 
00053 /**    
00054  * @brief Processing function for the Q15 FIR lattice filter.    
00055  * @param[in]  *S        points to an instance of the Q15 FIR lattice structure.    
00056  * @param[in]  *pSrc     points to the block of input data.    
00057  * @param[out] *pDst     points to the block of output data    
00058  * @param[in]  blockSize number of samples to process.    
00059  * @return none.    
00060  */
00061 
00062 void arm_fir_lattice_q15(
00063   const arm_fir_lattice_instance_q15 * S,
00064   q15_t * pSrc,
00065   q15_t * pDst,
00066   uint32_t blockSize)
00067 {
00068   q15_t *pState;                                 /* State pointer */
00069   q15_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
00070   q15_t *px;                                     /* temporary state pointer */
00071   q15_t *pk;                                     /* temporary coefficient pointer */
00072 
00073 
00074 #ifndef ARM_MATH_CM0_FAMILY
00075 
00076   /* Run the below code for Cortex-M4 and Cortex-M3 */
00077 
00078   q31_t fcurnt1, fnext1, gcurnt1 = 0, gnext1;    /* temporary variables for first sample in loop unrolling */
00079   q31_t fcurnt2, fnext2, gnext2;                 /* temporary variables for second sample in loop unrolling */
00080   q31_t fcurnt3, fnext3, gnext3;                 /* temporary variables for third sample in loop unrolling */
00081   q31_t fcurnt4, fnext4, gnext4;                 /* temporary variables for fourth sample in loop unrolling */
00082   uint32_t numStages = S->numStages;             /* Number of stages in the filter */
00083   uint32_t blkCnt, stageCnt;                     /* temporary variables for counts */
00084 
00085   pState = &S->pState[0];
00086 
00087   blkCnt = blockSize >> 2u;
00088 
00089   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
00090    ** a second loop below computes the remaining 1 to 3 samples. */
00091   while(blkCnt > 0u)
00092   {
00093 
00094     /* Read two samples from input buffer */
00095     /* f0(n) = x(n) */
00096     fcurnt1 = *pSrc++;
00097     fcurnt2 = *pSrc++;
00098 
00099     /* Initialize coeff pointer */
00100     pk = (pCoeffs);
00101 
00102     /* Initialize state pointer */
00103     px = pState;
00104 
00105     /* Read g0(n-1) from state */
00106     gcurnt1 = *px;
00107 
00108     /* Process first sample for first tap */
00109     /* f1(n) = f0(n) +  K1 * g0(n-1) */
00110     fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
00111     fnext1 = __SSAT(fnext1, 16);
00112 
00113     /* g1(n) = f0(n) * K1  +  g0(n-1) */
00114     gnext1 = (q31_t) ((fcurnt1 * (*pk)) >> 15u) + gcurnt1;
00115     gnext1 = __SSAT(gnext1, 16);
00116 
00117     /* Process second sample for first tap */
00118     /* for sample 2 processing */
00119     fnext2 = (q31_t) ((fcurnt1 * (*pk)) >> 15u) + fcurnt2;
00120     fnext2 = __SSAT(fnext2, 16);
00121 
00122     gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + fcurnt1;
00123     gnext2 = __SSAT(gnext2, 16);
00124 
00125 
00126     /* Read next two samples from input buffer */
00127     /* f0(n+2) = x(n+2) */
00128     fcurnt3 = *pSrc++;
00129     fcurnt4 = *pSrc++;
00130 
00131     /* Copy only last input samples into the state buffer    
00132        which is used for next four samples processing */
00133     *px++ = (q15_t) fcurnt4;
00134 
00135     /* Process third sample for first tap */
00136     fnext3 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + fcurnt3;
00137     fnext3 = __SSAT(fnext3, 16);
00138     gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + fcurnt2;
00139     gnext3 = __SSAT(gnext3, 16);
00140 
00141     /* Process fourth sample for first tap */
00142     fnext4 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + fcurnt4;
00143     fnext4 = __SSAT(fnext4, 16);
00144     gnext4 = (q31_t) ((fcurnt4 * (*pk++)) >> 15u) + fcurnt3;
00145     gnext4 = __SSAT(gnext4, 16);
00146 
00147     /* Update of f values for next coefficient set processing */
00148     fcurnt1 = fnext1;
00149     fcurnt2 = fnext2;
00150     fcurnt3 = fnext3;
00151     fcurnt4 = fnext4;
00152 
00153 
00154     /* Loop unrolling.  Process 4 taps at a time . */
00155     stageCnt = (numStages - 1u) >> 2;
00156 
00157 
00158     /* Loop over the number of taps.  Unroll by a factor of 4.    
00159      ** Repeat until we've computed numStages-3 coefficients. */
00160 
00161     /* Process 2nd, 3rd, 4th and 5th taps ... here */
00162     while(stageCnt > 0u)
00163     {
00164       /* Read g1(n-1), g3(n-1) .... from state */
00165       gcurnt1 = *px;
00166 
00167       /* save g1(n) in state buffer */
00168       *px++ = (q15_t) gnext4;
00169 
00170       /* Process first sample for 2nd, 6th .. tap */
00171       /* Sample processing for K2, K6.... */
00172       /* f1(n) = f0(n) +  K1 * g0(n-1) */
00173       fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
00174       fnext1 = __SSAT(fnext1, 16);
00175 
00176 
00177       /* Process second sample for 2nd, 6th .. tap */
00178       /* for sample 2 processing */
00179       fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
00180       fnext2 = __SSAT(fnext2, 16);
00181       /* Process third sample for 2nd, 6th .. tap */
00182       fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
00183       fnext3 = __SSAT(fnext3, 16);
00184       /* Process fourth sample for 2nd, 6th .. tap */
00185       /* fnext4 = fcurnt4 + (*pk) * gnext3; */
00186       fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
00187       fnext4 = __SSAT(fnext4, 16);
00188 
00189       /* g1(n) = f0(n) * K1  +  g0(n-1) */
00190       /* Calculation of state values for next stage */
00191       gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
00192       gnext4 = __SSAT(gnext4, 16);
00193       gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
00194       gnext3 = __SSAT(gnext3, 16);
00195 
00196       gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
00197       gnext2 = __SSAT(gnext2, 16);
00198 
00199       gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
00200       gnext1 = __SSAT(gnext1, 16);
00201 
00202 
00203       /* Read g2(n-1), g4(n-1) .... from state */
00204       gcurnt1 = *px;
00205 
00206       /* save g1(n) in state buffer */
00207       *px++ = (q15_t) gnext4;
00208 
00209       /* Sample processing for K3, K7.... */
00210       /* Process first sample for 3rd, 7th .. tap */
00211       /* f3(n) = f2(n) +  K3 * g2(n-1) */
00212       fcurnt1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fnext1;
00213       fcurnt1 = __SSAT(fcurnt1, 16);
00214 
00215       /* Process second sample for 3rd, 7th .. tap */
00216       fcurnt2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fnext2;
00217       fcurnt2 = __SSAT(fcurnt2, 16);
00218 
00219       /* Process third sample for 3rd, 7th .. tap */
00220       fcurnt3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fnext3;
00221       fcurnt3 = __SSAT(fcurnt3, 16);
00222 
00223       /* Process fourth sample for 3rd, 7th .. tap */
00224       fcurnt4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fnext4;
00225       fcurnt4 = __SSAT(fcurnt4, 16);
00226 
00227       /* Calculation of state values for next stage */
00228       /* g3(n) = f2(n) * K3  +  g2(n-1) */
00229       gnext4 = (q31_t) ((fnext4 * (*pk)) >> 15u) + gnext3;
00230       gnext4 = __SSAT(gnext4, 16);
00231 
00232       gnext3 = (q31_t) ((fnext3 * (*pk)) >> 15u) + gnext2;
00233       gnext3 = __SSAT(gnext3, 16);
00234 
00235       gnext2 = (q31_t) ((fnext2 * (*pk)) >> 15u) + gnext1;
00236       gnext2 = __SSAT(gnext2, 16);
00237 
00238       gnext1 = (q31_t) ((fnext1 * (*pk++)) >> 15u) + gcurnt1;
00239       gnext1 = __SSAT(gnext1, 16);
00240 
00241       /* Read g1(n-1), g3(n-1) .... from state */
00242       gcurnt1 = *px;
00243 
00244       /* save g1(n) in state buffer */
00245       *px++ = (q15_t) gnext4;
00246 
00247       /* Sample processing for K4, K8.... */
00248       /* Process first sample for 4th, 8th .. tap */
00249       /* f4(n) = f3(n) +  K4 * g3(n-1) */
00250       fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
00251       fnext1 = __SSAT(fnext1, 16);
00252 
00253       /* Process second sample for 4th, 8th .. tap */
00254       /* for sample 2 processing */
00255       fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
00256       fnext2 = __SSAT(fnext2, 16);
00257 
00258       /* Process third sample for 4th, 8th .. tap */
00259       fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
00260       fnext3 = __SSAT(fnext3, 16);
00261 
00262       /* Process fourth sample for 4th, 8th .. tap */
00263       fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
00264       fnext4 = __SSAT(fnext4, 16);
00265 
00266       /* g4(n) = f3(n) * K4  +  g3(n-1) */
00267       /* Calculation of state values for next stage */
00268       gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
00269       gnext4 = __SSAT(gnext4, 16);
00270 
00271       gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
00272       gnext3 = __SSAT(gnext3, 16);
00273 
00274       gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
00275       gnext2 = __SSAT(gnext2, 16);
00276       gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
00277       gnext1 = __SSAT(gnext1, 16);
00278 
00279 
00280       /* Read g2(n-1), g4(n-1) .... from state */
00281       gcurnt1 = *px;
00282 
00283       /* save g4(n) in state buffer */
00284       *px++ = (q15_t) gnext4;
00285 
00286       /* Sample processing for K5, K9.... */
00287       /* Process first sample for 5th, 9th .. tap */
00288       /* f5(n) = f4(n) +  K5 * g4(n-1) */
00289       fcurnt1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fnext1;
00290       fcurnt1 = __SSAT(fcurnt1, 16);
00291 
00292       /* Process second sample for 5th, 9th .. tap */
00293       fcurnt2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fnext2;
00294       fcurnt2 = __SSAT(fcurnt2, 16);
00295 
00296       /* Process third sample for 5th, 9th .. tap */
00297       fcurnt3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fnext3;
00298       fcurnt3 = __SSAT(fcurnt3, 16);
00299 
00300       /* Process fourth sample for 5th, 9th .. tap */
00301       fcurnt4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fnext4;
00302       fcurnt4 = __SSAT(fcurnt4, 16);
00303 
00304       /* Calculation of state values for next stage */
00305       /* g5(n) = f4(n) * K5  +  g4(n-1) */
00306       gnext4 = (q31_t) ((fnext4 * (*pk)) >> 15u) + gnext3;
00307       gnext4 = __SSAT(gnext4, 16);
00308       gnext3 = (q31_t) ((fnext3 * (*pk)) >> 15u) + gnext2;
00309       gnext3 = __SSAT(gnext3, 16);
00310       gnext2 = (q31_t) ((fnext2 * (*pk)) >> 15u) + gnext1;
00311       gnext2 = __SSAT(gnext2, 16);
00312       gnext1 = (q31_t) ((fnext1 * (*pk++)) >> 15u) + gcurnt1;
00313       gnext1 = __SSAT(gnext1, 16);
00314 
00315       stageCnt--;
00316     }
00317 
00318     /* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */
00319     stageCnt = (numStages - 1u) % 0x4u;
00320 
00321     while(stageCnt > 0u)
00322     {
00323       gcurnt1 = *px;
00324 
00325       /* save g value in state buffer */
00326       *px++ = (q15_t) gnext4;
00327 
00328       /* Process four samples for last three taps here */
00329       fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
00330       fnext1 = __SSAT(fnext1, 16);
00331       fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
00332       fnext2 = __SSAT(fnext2, 16);
00333 
00334       fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
00335       fnext3 = __SSAT(fnext3, 16);
00336 
00337       fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
00338       fnext4 = __SSAT(fnext4, 16);
00339 
00340       /* g1(n) = f0(n) * K1  +  g0(n-1) */
00341       gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
00342       gnext4 = __SSAT(gnext4, 16);
00343       gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
00344       gnext3 = __SSAT(gnext3, 16);
00345       gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
00346       gnext2 = __SSAT(gnext2, 16);
00347       gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
00348       gnext1 = __SSAT(gnext1, 16);
00349 
00350       /* Update of f values for next coefficient set processing */
00351       fcurnt1 = fnext1;
00352       fcurnt2 = fnext2;
00353       fcurnt3 = fnext3;
00354       fcurnt4 = fnext4;
00355 
00356       stageCnt--;
00357 
00358     }
00359 
00360     /* The results in the 4 accumulators, store in the destination buffer. */
00361     /* y(n) = fN(n) */
00362 
00363 #ifndef  ARM_MATH_BIG_ENDIAN
00364 
00365     *__SIMD32(pDst)++ = __PKHBT(fcurnt1, fcurnt2, 16);
00366     *__SIMD32(pDst)++ = __PKHBT(fcurnt3, fcurnt4, 16);
00367 
00368 #else
00369 
00370     *__SIMD32(pDst)++ = __PKHBT(fcurnt2, fcurnt1, 16);
00371     *__SIMD32(pDst)++ = __PKHBT(fcurnt4, fcurnt3, 16);
00372 
00373 #endif /*      #ifndef  ARM_MATH_BIG_ENDIAN    */
00374 
00375     blkCnt--;
00376   }
00377 
00378   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
00379    ** No loop unrolling is used. */
00380   blkCnt = blockSize % 0x4u;
00381 
00382   while(blkCnt > 0u)
00383   {
00384     /* f0(n) = x(n) */
00385     fcurnt1 = *pSrc++;
00386 
00387     /* Initialize coeff pointer */
00388     pk = (pCoeffs);
00389 
00390     /* Initialize state pointer */
00391     px = pState;
00392 
00393     /* read g2(n) from state buffer */
00394     gcurnt1 = *px;
00395 
00396     /* for sample 1 processing */
00397     /* f1(n) = f0(n) +  K1 * g0(n-1) */
00398     fnext1 = (((q31_t) gcurnt1 * (*pk)) >> 15u) + fcurnt1;
00399     fnext1 = __SSAT(fnext1, 16);
00400 
00401 
00402     /* g1(n) = f0(n) * K1  +  g0(n-1) */
00403     gnext1 = (((q31_t) fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
00404     gnext1 = __SSAT(gnext1, 16);
00405 
00406     /* save g1(n) in state buffer */
00407     *px++ = (q15_t) fcurnt1;
00408 
00409     /* f1(n) is saved in fcurnt1    
00410        for next stage processing */
00411     fcurnt1 = fnext1;
00412 
00413     stageCnt = (numStages - 1u);
00414 
00415     /* stage loop */
00416     while(stageCnt > 0u)
00417     {
00418       /* read g2(n) from state buffer */
00419       gcurnt1 = *px;
00420 
00421       /* save g1(n) in state buffer */
00422       *px++ = (q15_t) gnext1;
00423 
00424       /* Sample processing for K2, K3.... */
00425       /* f2(n) = f1(n) +  K2 * g1(n-1) */
00426       fnext1 = (((q31_t) gcurnt1 * (*pk)) >> 15u) + fcurnt1;
00427       fnext1 = __SSAT(fnext1, 16);
00428 
00429       /* g2(n) = f1(n) * K2  +  g1(n-1) */
00430       gnext1 = (((q31_t) fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
00431       gnext1 = __SSAT(gnext1, 16);
00432 
00433 
00434       /* f1(n) is saved in fcurnt1    
00435          for next stage processing */
00436       fcurnt1 = fnext1;
00437 
00438       stageCnt--;
00439 
00440     }
00441 
00442     /* y(n) = fN(n) */
00443     *pDst++ = __SSAT(fcurnt1, 16);
00444 
00445 
00446     blkCnt--;
00447 
00448   }
00449 
00450 #else
00451 
00452   /* Run the below code for Cortex-M0 */
00453 
00454   q31_t fcurnt, fnext, gcurnt, gnext;            /* temporary variables */
00455   uint32_t numStages = S->numStages;             /* Length of the filter */
00456   uint32_t blkCnt, stageCnt;                     /* temporary variables for counts */
00457 
00458   pState = &S->pState[0];
00459 
00460   blkCnt = blockSize;
00461 
00462   while(blkCnt > 0u)
00463   {
00464     /* f0(n) = x(n) */
00465     fcurnt = *pSrc++;
00466 
00467     /* Initialize coeff pointer */
00468     pk = (pCoeffs);
00469 
00470     /* Initialize state pointer */
00471     px = pState;
00472 
00473     /* read g0(n-1) from state buffer */
00474     gcurnt = *px;
00475 
00476     /* for sample 1 processing */
00477     /* f1(n) = f0(n) +  K1 * g0(n-1) */
00478     fnext = ((gcurnt * (*pk)) >> 15u) + fcurnt;
00479     fnext = __SSAT(fnext, 16);
00480 
00481 
00482     /* g1(n) = f0(n) * K1  +  g0(n-1) */
00483     gnext = ((fcurnt * (*pk++)) >> 15u) + gcurnt;
00484     gnext = __SSAT(gnext, 16);
00485 
00486     /* save f0(n) in state buffer */
00487     *px++ = (q15_t) fcurnt;
00488 
00489     /* f1(n) is saved in fcurnt            
00490        for next stage processing */
00491     fcurnt = fnext;
00492 
00493     stageCnt = (numStages - 1u);
00494 
00495     /* stage loop */
00496     while(stageCnt > 0u)
00497     {
00498       /* read g1(n-1) from state buffer */
00499       gcurnt = *px;
00500 
00501       /* save g0(n-1) in state buffer */
00502       *px++ = (q15_t) gnext;
00503 
00504       /* Sample processing for K2, K3.... */
00505       /* f2(n) = f1(n) +  K2 * g1(n-1) */
00506       fnext = ((gcurnt * (*pk)) >> 15u) + fcurnt;
00507       fnext = __SSAT(fnext, 16);
00508 
00509       /* g2(n) = f1(n) * K2  +  g1(n-1) */
00510       gnext = ((fcurnt * (*pk++)) >> 15u) + gcurnt;
00511       gnext = __SSAT(gnext, 16);
00512 
00513 
00514       /* f1(n) is saved in fcurnt            
00515          for next stage processing */
00516       fcurnt = fnext;
00517 
00518       stageCnt--;
00519 
00520     }
00521 
00522     /* y(n) = fN(n) */
00523     *pDst++ = __SSAT(fcurnt, 16);
00524 
00525 
00526     blkCnt--;
00527 
00528   }
00529 
00530 #endif /*   #ifndef ARM_MATH_CM0_FAMILY */
00531 
00532 }
00533 
00534 /**    
00535  * @} end of FIR_Lattice group    
00536  */