k60-keil

K60-Keil版本（下载安装MDK4.23）

      fcurr3 = fnext3 + ((*pk) * gnext2);
      /* Process fourth sample for 3rd, 7th .. tap */
      fcurr4 = fnext4 + ((*pk) * gnext3);

      /* Calculation of state values for next stage */
      /* g3(n) = f2(n) * K3  +  g2(n-1) */
      gnext4 = (fnext4 * (*pk)) + gnext3;
      gnext3 = (fnext3 * (*pk)) + gnext2;
      gnext2 = (fnext2 * (*pk)) + gnext1;
      gnext1 = (fnext1 * (*pk++)) + gcurr1;


      /* Read g1(n-1), g3(n-1) .... from state */
      gcurr1 = *px;

      /* save g3(n) in state buffer */
      *px++ = gnext4;

      /* Sample processing for K4, K8.... */
      /* Process first sample for 4th, 8th .. tap */
      /* f4(n) = f3(n) +  K4 * g3(n-1) */
      fnext1 = fcurr1 + ((*pk) * gcurr1);
      /* Process second sample for 4th, 8th .. tap */
      /* for sample 2 processing */
      fnext2 = fcurr2 + ((*pk) * gnext1);
      /* Process third sample for 4th, 8th .. tap */
      fnext3 = fcurr3 + ((*pk) * gnext2);
      /* Process fourth sample for 4th, 8th .. tap */
      fnext4 = fcurr4 + ((*pk) * gnext3);

      /* g4(n) = f3(n) * K4  +  g3(n-1) */
      /* Calculation of state values for next stage */
      gnext4 = (fcurr4 * (*pk)) + gnext3;
      gnext3 = (fcurr3 * (*pk)) + gnext2;
      gnext2 = (fcurr2 * (*pk)) + gnext1;
      gnext1 = (fcurr1 * (*pk++)) + gcurr1;

      /* Read g2(n-1), g4(n-1) .... from state */
      gcurr1 = *px;

      /* save g4(n) in state buffer */
      *px++ = gnext4;

      /* Sample processing for K5, K9.... */
      /* Process first sample for 5th, 9th .. tap */
      /* f5(n) = f4(n) +  K5 * g4(n-1) */
      fcurr1 = fnext1 + ((*pk) * gcurr1);
      /* Process second sample for 5th, 9th .. tap */
      fcurr2 = fnext2 + ((*pk) * gnext1);
      /* Process third sample for 5th, 9th .. tap */
      fcurr3 = fnext3 + ((*pk) * gnext2);
      /* Process fourth sample for 5th, 9th .. tap */
      fcurr4 = fnext4 + ((*pk) * gnext3);

      /* Calculation of state values for next stage */
      /* g5(n) = f4(n) * K5  +  g4(n-1) */
      gnext4 = (fnext4 * (*pk)) + gnext3;
      gnext3 = (fnext3 * (*pk)) + gnext2;
      gnext2 = (fnext2 * (*pk)) + gnext1;
      gnext1 = (fnext1 * (*pk++)) + gcurr1;

      stageCnt--;
    }

    /* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */
    stageCnt = (numStages - 1u) % 0x4u;

    while(stageCnt > 0u)
    {
      gcurr1 = *px;

      /* save g value in state buffer */
      *px++ = gnext4;

      /* Process four samples for last three taps here */
      fnext1 = fcurr1 + ((*pk) * gcurr1);
      fnext2 = fcurr2 + ((*pk) * gnext1);
      fnext3 = fcurr3 + ((*pk) * gnext2);
      fnext4 = fcurr4 + ((*pk) * gnext3);

      /* g1(n) = f0(n) * K1  +  g0(n-1) */
      gnext4 = (fcurr4 * (*pk)) + gnext3;
      gnext3 = (fcurr3 * (*pk)) + gnext2;
      gnext2 = (fcurr2 * (*pk)) + gnext1;
      gnext1 = (fcurr1 * (*pk++)) + gcurr1;

      /* Update of f values for next coefficient set processing */
      fcurr1 = fnext1;
      fcurr2 = fnext2;
      fcurr3 = fnext3;
      fcurr4 = fnext4;

      stageCnt--;

    }

    /* The results in the 4 accumulators, store in the destination buffer. */
    /* y(n) = fN(n) */
    *pDst++ = fcurr1;
    *pDst++ = fcurr2;
    *pDst++ = fcurr3;
    *pDst++ = fcurr4;

    blkCnt--;
  }

  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.   
   ** No loop unrolling is used. */
  blkCnt = blockSize % 0x4u;

  while(blkCnt > 0u)
  {
    /* f0(n) = x(n) */
    fcurr1 = *pSrc++;

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

    /* Initialize state pointer */
    px = pState;

    /* read g2(n) from state buffer */
    gcurr1 = *px;

    /* for sample 1 processing */
    /* f1(n) = f0(n) +  K1 * g0(n-1) */
    fnext1 = fcurr1 + ((*pk) * gcurr1);
    /* g1(n) = f0(n) * K1  +  g0(n-1) */
    gnext1 = (fcurr1 * (*pk++)) + gcurr1;

    /* save g1(n) in state buffer */
    *px++ = fcurr1;

    /* f1(n) is saved in fcurr1   
       for next stage processing */
    fcurr1 = fnext1;

    stageCnt = (numStages - 1u);

    /* stage loop */
    while(stageCnt > 0u)
    {
      /* read g2(n) from state buffer */
      gcurr1 = *px;

      /* save g1(n) in state buffer */
      *px++ = gnext1;

      /* Sample processing for K2, K3.... */
      /* f2(n) = f1(n) +  K2 * g1(n-1) */
      fnext1 = fcurr1 + ((*pk) * gcurr1);
      /* g2(n) = f1(n) * K2  +  g1(n-1) */
      gnext1 = (fcurr1 * (*pk++)) + gcurr1;

      /* f1(n) is saved in fcurr1   
         for next stage processing */
      fcurr1 = fnext1;

      stageCnt--;

    }

    /* y(n) = fN(n) */
    *pDst++ = fcurr1;

    blkCnt--;

  }

#else

  /* Run the below code for Cortex-M0 */

  float32_t fcurr, fnext, gcurr, gnext;          /* temporary variables */
  uint32_t numStages = S->numStages;             /* Length of the filter */
  uint32_t blkCnt, stageCnt;                     /* temporary variables for counts */

  pState = &S->pState[0];

  blkCnt = blockSize;

  while(blkCnt > 0u)
  {
    /* f0(n) = x(n) */
    fcurr = *pSrc++;

    /* Initialize coeff pointer */
    pk = pCoeffs;

    /* Initialize state pointer */
    px = pState;

    /* read g0(n-1) from state buffer */
    gcurr = *px;

    /* for sample 1 processing */
    /* f1(n) = f0(n) +  K1 * g0(n-1) */
    fnext = fcurr + ((*pk) * gcurr);
    /* g1(n) = f0(n) * K1  +  g0(n-1) */
    gnext = (fcurr * (*pk++)) + gcurr;

    /* save f0(n) in state buffer */
    *px++ = fcurr;

    /* f1(n) is saved in fcurr           
       for next stage processing */
    fcurr = fnext;

    stageCnt = (numStages - 1u);

    /* stage loop */
    while(stageCnt > 0u)
    {
      /* read g2(n) from state buffer */
      gcurr = *px;

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

      /* Sample processing for K2, K3.... */
      /* f2(n) = f1(n) +  K2 * g1(n-1) */
      fnext = fcurr + ((*pk) * gcurr);
      /* g2(n) = f1(n) * K2  +  g1(n-1) */
      gnext = (fcurr * (*pk++)) + gcurr;

      /* f1(n) is saved in fcurr1           
         for next stage processing */
      fcurr = fnext;

      stageCnt--;

    }

    /* y(n) = fN(n) */
    *pDst++ = fcurr;

    blkCnt--;

  }

#endif /*   #ifndef ARM_MATH_CM0 */

}

/**   
 * @} end of FIR_Lattice group   
 */