k60-keil

K60-Keil版本（下载安装MDK4.23）

/* ----------------------------------------------------------------------   
* Copyright (C) 2010 ARM Limited. All rights reserved.   
*   
* $Date:        15. July 2011  
* $Revision: 	V1.0.10  
*   
* Project: 	    CMSIS DSP Library   
* Title:	    arm_fir_lattice_q15.c   
*   
* Description:	Q15 FIR lattice filter processing function.   
*   
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*  
* Version 1.0.10 2011/7/15 
*    Big Endian support added and Merged M0 and M3/M4 Source code.  
*   
* Version 1.0.3 2010/11/29  
*    Re-organized the CMSIS folders and updated documentation.   
*    
* Version 1.0.2 2010/11/11   
*    Documentation updated.    
*   
* Version 1.0.1 2010/10/05    
*    Production release and review comments incorporated.   
*   
* Version 1.0.0 2010/09/20    
*    Production release and review comments incorporated   
*   
* Version 0.0.7  2010/06/10    
*    Misra-C changes done   
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**   
 * @ingroup groupFilters   
 */

/**   
 * @addtogroup FIR_Lattice   
 * @{   
 */


/**   
 * @brief Processing function for the Q15 FIR lattice filter.   
 * @param[in]  *S        points to an instance of the Q15 FIR lattice structure.   
 * @param[in]  *pSrc     points to the block of input data.   
 * @param[out] *pDst     points to the block of output data   
 * @param[in]  blockSize number of samples to process.   
 * @return none.   
 */

void arm_fir_lattice_q15(
  const arm_fir_lattice_instance_q15 * S,
  q15_t * pSrc,
  q15_t * pDst,
  uint32_t blockSize)
{
  q15_t *pState;                                 /* State pointer */
  q15_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
  q15_t *px;                                     /* temporary state pointer */
  q15_t *pk;                                     /* temporary coefficient pointer */


#ifndef ARM_MATH_CM0

  /* Run the below code for Cortex-M4 and Cortex-M3 */

  q31_t fcurnt1, fnext1, gcurnt1 = 0, gnext1;    /* temporary variables for first sample in loop unrolling */
  q31_t fcurnt2, fnext2, gnext2;                 /* temporary variables for second sample in loop unrolling */
  q31_t fcurnt3, fnext3, gnext3;                 /* temporary variables for third sample in loop unrolling */
  q31_t fcurnt4, fnext4, gnext4;                 /* temporary variables for fourth sample in loop unrolling */
  uint32_t numStages = S->numStages;             /* Number of stages in the filter */
  uint32_t blkCnt, stageCnt;                     /* temporary variables for counts */

  pState = &S->pState[0];

  blkCnt = blockSize >> 2u;

  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.   
   ** a second loop below computes the remaining 1 to 3 samples. */
  while(blkCnt > 0u)
  {

    /* Read two samples from input buffer */
    /* f0(n) = x(n) */
    fcurnt1 = *pSrc++;
    fcurnt2 = *pSrc++;

    /* Initialize coeff pointer */
    pk = (pCoeffs);

    /* Initialize state pointer */
    px = pState;

    /* Read g0(n-1) from state */
    gcurnt1 = *px;

    /* Process first sample for first tap */
    /* f1(n) = f0(n) +  K1 * g0(n-1) */
    fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
    fnext1 = __SSAT(fnext1, 16);

    /* g1(n) = f0(n) * K1  +  g0(n-1) */
    gnext1 = (q31_t) ((fcurnt1 * (*pk)) >> 15u) + gcurnt1;
    gnext1 = __SSAT(gnext1, 16);

    /* Process second sample for first tap */
    /* for sample 2 processing */
    fnext2 = (q31_t) ((fcurnt1 * (*pk)) >> 15u) + fcurnt2;
    fnext2 = __SSAT(fnext2, 16);

    gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + fcurnt1;
    gnext2 = __SSAT(gnext2, 16);


    /* Read next two samples from input buffer */
    /* f0(n+2) = x(n+2) */
    fcurnt3 = *pSrc++;
    fcurnt4 = *pSrc++;

    /* Copy only last input samples into the state buffer   
       which is used for next four samples processing */
    *px++ = (q15_t) fcurnt4;

    /* Process third sample for first tap */
    fnext3 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + fcurnt3;
    fnext3 = __SSAT(fnext3, 16);
    gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + fcurnt2;
    gnext3 = __SSAT(gnext3, 16);

    /* Process fourth sample for first tap */
    fnext4 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + fcurnt4;
    fnext4 = __SSAT(fnext4, 16);
    gnext4 = (q31_t) ((fcurnt4 * (*pk++)) >> 15u) + fcurnt3;
    gnext4 = __SSAT(gnext4, 16);

    /* Update of f values for next coefficient set processing */
    fcurnt1 = fnext1;
    fcurnt2 = fnext2;
    fcurnt3 = fnext3;
    fcurnt4 = fnext4;


    /* Loop unrolling.  Process 4 taps at a time . */
    stageCnt = (numStages - 1u) >> 2;


    /* Loop over the number of taps.  Unroll by a factor of 4.   
     ** Repeat until we've computed numStages-3 coefficients. */

    /* Process 2nd, 3rd, 4th and 5th taps ... here */
    while(stageCnt > 0u)
    {
      /* Read g1(n-1), g3(n-1) .... from state */
      gcurnt1 = *px;

      /* save g1(n) in state buffer */
      *px++ = (q15_t) gnext4;

      /* Process first sample for 2nd, 6th .. tap */
      /* Sample processing for K2, K6.... */
      /* f1(n) = f0(n) +  K1 * g0(n-1) */
      fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
      fnext1 = __SSAT(fnext1, 16);


      /* Process second sample for 2nd, 6th .. tap */
      /* for sample 2 processing */
      fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
      fnext2 = __SSAT(fnext2, 16);
      /* Process third sample for 2nd, 6th .. tap */
      fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
      fnext3 = __SSAT(fnext3, 16);
      /* Process fourth sample for 2nd, 6th .. tap */
      /* fnext4 = fcurnt4 + (*pk) * gnext3; */
      fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
      fnext4 = __SSAT(fnext4, 16);

      /* g1(n) = f0(n) * K1  +  g0(n-1) */
      /* Calculation of state values for next stage */
      gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
      gnext4 = __SSAT(gnext4, 16);
      gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
      gnext3 = __SSAT(gnext3, 16);

      gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1;
      gnext2 = __SSAT(gnext2, 16);

      gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
      gnext1 = __SSAT(gnext1, 16);


      /* Read g2(n-1), g4(n-1) .... from state */
      gcurnt1 = *px;

      /* save g1(n) in state buffer */
      *px++ = (q15_t) gnext4;

      /* Sample processing for K3, K7.... */
      /* Process first sample for 3rd, 7th .. tap */
      /* f3(n) = f2(n) +  K3 * g2(n-1) */
      fcurnt1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fnext1;
      fcurnt1 = __SSAT(fcurnt1, 16);

      /* Process second sample for 3rd, 7th .. tap */
      fcurnt2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fnext2;
      fcurnt2 = __SSAT(fcurnt2, 16);

      /* Process third sample for 3rd, 7th .. tap */
      fcurnt3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fnext3;
      fcurnt3 = __SSAT(fcurnt3, 16);

      /* Process fourth sample for 3rd, 7th .. tap */
      fcurnt4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fnext4;
      fcurnt4 = __SSAT(fcurnt4, 16);

      /* Calculation of state values for next stage */
      /* g3(n) = f2(n) * K3  +  g2(n-1) */
      gnext4 = (q31_t) ((fnext4 * (*pk)) >> 15u) + gnext3;
      gnext4 = __SSAT(gnext4, 16);

      gnext3 = (q31_t) ((fnext3 * (*pk)) >> 15u) + gnext2;
      gnext3 = __SSAT(gnext3, 16);

      gnext2 = (q31_t) ((fnext2 * (*pk)) >> 15u) + gnext1;
      gnext2 = __SSAT(gnext2, 16);

      gnext1 = (q31_t) ((fnext1 * (*pk++)) >> 15u) + gcurnt1;
      gnext1 = __SSAT(gnext1, 16);

      /* Read g1(n-1), g3(n-1) .... from state */
      gcurnt1 = *px;

      /* save g1(n) in state buffer */
      *px++ = (q15_t) gnext4;

      /* Sample processing for K4, K8.... */
      /* Process first sample for 4th, 8th .. tap */
      /* f4(n) = f3(n) +  K4 * g3(n-1) */
      fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
      fnext1 = __SSAT(fnext1, 16);

      /* Process second sample for 4th, 8th .. tap */
      /* for sample 2 processing */
      fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
      fnext2 = __SSAT(fnext2, 16);

      /* Process third sample for 4th, 8th .. tap */
      fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
      fnext3 = __SSAT(fnext3, 16);

      /* Process fourth sample for 4th, 8th .. tap */
      fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
      fnext4 = __SSAT(fnext4, 16);

      /* g4(n) = f3(n) * K4  +  g3(n-1) */
      /* Calculation of state values for next stage */
      gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3;
      gnext4 = __SSAT(gnext4, 16);

      gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2;
      gnext3 = __SSAT(gnext3, 16);