Diff: FilteringFunctions/arm_fir_lattice_f32.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FilteringFunctions/arm_fir_lattice_f32.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,506 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:	    arm_fir_lattice_f32.c    
+*    
+* Description:	Processing function for the floating-point FIR Lattice filter.    
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Redistribution and use in source and binary forms, with or without 
+* modification, are permitted provided that the following conditions
+* are met:
+*   - Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*   - Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in
+*     the documentation and/or other materials provided with the 
+*     distribution.
+*   - Neither the name of ARM LIMITED nor the names of its contributors
+*     may be used to endorse or promote products derived from this
+*     software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.   
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupFilters    
+ */
+
+/**    
+ * @defgroup FIR_Lattice Finite Impulse Response (FIR) Lattice Filters    
+ *    
+ * This set of functions implements Finite Impulse Response (FIR) lattice filters    
+ * for Q15, Q31 and floating-point data types.  Lattice filters are used in a     
+ * variety of adaptive filter applications.  The filter structure is feedforward and    
+ * the net impulse response is finite length.    
+ * The functions operate on blocks    
+ * of input and output data and each call to the function processes    
+ * <code>blockSize</code> samples through the filter.  <code>pSrc</code> and    
+ * <code>pDst</code> point to input and output arrays containing <code>blockSize</code> values.    
+ *    
+ * \par Algorithm:    
+ * \image html FIRLattice.gif "Finite Impulse Response Lattice filter"    
+ * The following difference equation is implemented:    
+ * <pre>    
+ *    f0[n] = g0[n] = x[n]    
+ *    fm[n] = fm-1[n] + km * gm-1[n-1] for m = 1, 2, ...M    
+ *    gm[n] = km * fm-1[n] + gm-1[n-1] for m = 1, 2, ...M    
+ *    y[n] = fM[n]    
+ * </pre>    
+ * \par    
+ * <code>pCoeffs</code> points to tha array of reflection coefficients of size <code>numStages</code>.    
+ * Reflection Coefficients are stored in the following order.    
+ * \par    
+ * <pre>    
+ *    {k1, k2, ..., kM}    
+ * </pre>    
+ * where M is number of stages    
+ * \par    
+ * <code>pState</code> points to a state array of size <code>numStages</code>.    
+ * The state variables (g values) hold previous inputs and are stored in the following order.    
+ * <pre>    
+ *    {g0[n], g1[n], g2[n] ...gM-1[n]}    
+ * </pre>    
+ * The state variables are updated after each block of data is processed; the coefficients are untouched.    
+ * \par Instance Structure    
+ * The coefficients and state variables for a filter are stored together in an instance data structure.    
+ * A separate instance structure must be defined for each filter.    
+ * Coefficient arrays may be shared among several instances while state variable arrays cannot be shared.    
+ * There are separate instance structure declarations for each of the 3 supported data types.    
+ *    
+ * \par Initialization Functions    
+ * There is also an associated initialization function for each data type.    
+ * The initialization function performs the following operations:    
+ * - Sets the values of the internal structure fields.    
+ * - Zeros out the values in the state buffer.    
+ * To do this manually without calling the init function, assign the follow subfields of the instance structure:
+ * numStages, pCoeffs, pState. Also set all of the values in pState to zero. 
+ *    
+ * \par    
+ * Use of the initialization function is optional.    
+ * However, if the initialization function is used, then the instance structure cannot be placed into a const data section.    
+ * To place an instance structure into a const data section, the instance structure must be manually initialized.    
+ * Set the values in the state buffer to zeros and then manually initialize the instance structure as follows:    
+ * <pre>    
+ *arm_fir_lattice_instance_f32 S = {numStages, pState, pCoeffs};    
+ *arm_fir_lattice_instance_q31 S = {numStages, pState, pCoeffs};    
+ *arm_fir_lattice_instance_q15 S = {numStages, pState, pCoeffs};    
+ * </pre>    
+ * \par    
+ * where <code>numStages</code> is the number of stages in the filter; <code>pState</code> is the address of the state buffer;    
+ * <code>pCoeffs</code> is the address of the coefficient buffer.    
+ * \par Fixed-Point Behavior    
+ * Care must be taken when using the fixed-point versions of the FIR Lattice filter functions.    
+ * In particular, the overflow and saturation behavior of the accumulator used in each function must be considered.    
+ * Refer to the function specific documentation below for usage guidelines.    
+ */
+
+/**    
+ * @addtogroup FIR_Lattice    
+ * @{    
+ */
+
+
+  /**    
+   * @brief Processing function for the floating-point FIR lattice filter.    
+   * @param[in]  *S        points to an instance of the floating-point 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_f32(
+  const arm_fir_lattice_instance_f32 * S,
+  float32_t * pSrc,
+  float32_t * pDst,
+  uint32_t blockSize)
+{
+  float32_t *pState;                             /* State pointer */
+  float32_t *pCoeffs = S->pCoeffs;               /* Coefficient pointer */
+  float32_t *px;                                 /* temporary state pointer */
+  float32_t *pk;                                 /* temporary coefficient pointer */
+
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  float32_t fcurr1, fnext1, gcurr1, gnext1;      /* temporary variables for first sample in loop unrolling */
+  float32_t fcurr2, fnext2, gnext2;              /* temporary variables for second sample in loop unrolling */
+  float32_t fcurr3, fnext3, gnext3;              /* temporary variables for third sample in loop unrolling */
+  float32_t fcurr4, 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 */
+
+  gcurr1 = 0.0f;
+  pState = &S->pState[0];
+
+  blkCnt = blockSize >> 2;
+
+  /* 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) */
+    fcurr1 = *pSrc++;
+    fcurr2 = *pSrc++;
+
+    /* Initialize coeff pointer */
+    pk = (pCoeffs);
+
+    /* Initialize state pointer */
+    px = pState;
+
+    /* Read g0(n-1) from state */
+    gcurr1 = *px;
+
+    /* Process first sample for first tap */
+    /* f1(n) = f0(n) +  K1 * g0(n-1) */
+    fnext1 = fcurr1 + ((*pk) * gcurr1);
+    /* g1(n) = f0(n) * K1  +  g0(n-1) */
+    gnext1 = (fcurr1 * (*pk)) + gcurr1;
+
+    /* Process second sample for first tap */
+    /* for sample 2 processing */
+    fnext2 = fcurr2 + ((*pk) * fcurr1);
+    gnext2 = (fcurr2 * (*pk)) + fcurr1;
+
+    /* Read next two samples from input buffer */
+    /* f0(n+2) = x(n+2) */
+    fcurr3 = *pSrc++;
+    fcurr4 = *pSrc++;
+
+    /* Copy only last input samples into the state buffer    
+       which will be used for next four samples processing */
+    *px++ = fcurr4;
+
+    /* Process third sample for first tap */
+    fnext3 = fcurr3 + ((*pk) * fcurr2);
+    gnext3 = (fcurr3 * (*pk)) + fcurr2;
+
+    /* Process fourth sample for first tap */
+    fnext4 = fcurr4 + ((*pk) * fcurr3);
+    gnext4 = (fcurr4 * (*pk++)) + fcurr3;
+
+    /* Update of f values for next coefficient set processing */
+    fcurr1 = fnext1;
+    fcurr2 = fnext2;
+    fcurr3 = fnext3;
+    fcurr4 = fnext4;
+
+    /* Loop unrolling.  Process 4 taps at a time . */
+    stageCnt = (numStages - 1u) >> 2u;
+
+    /* 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 */
+      gcurr1 = *px;
+
+      /* save g1(n) in state buffer */
+      *px++ = gnext4;
+
+      /* Process first sample for 2nd, 6th .. tap */
+      /* Sample processing for K2, K6.... */
+      /* f2(n) = f1(n) +  K2 * g1(n-1) */
+      fnext1 = fcurr1 + ((*pk) * gcurr1);
+      /* Process second sample for 2nd, 6th .. tap */
+      /* for sample 2 processing */
+      fnext2 = fcurr2 + ((*pk) * gnext1);
+      /* Process third sample for 2nd, 6th .. tap */
+      fnext3 = fcurr3 + ((*pk) * gnext2);
+      /* Process fourth sample for 2nd, 6th .. tap */
+      fnext4 = fcurr4 + ((*pk) * gnext3);
+
+      /* g2(n) = f1(n) * K2  +  g1(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 g2(n) in state buffer */
+      *px++ = gnext4;
+
+      /* Sample processing for K3, K7.... */
+      /* Process first sample for 3rd, 7th .. tap */
+      /* f3(n) = f2(n) +  K3 * g2(n-1) */
+      fcurr1 = fnext1 + ((*pk) * gcurr1);
+      /* Process second sample for 3rd, 7th .. tap */
+      fcurr2 = fnext2 + ((*pk) * gnext1);
+      /* Process third sample for 3rd, 7th .. tap */
+      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_FAMILY */
+
+}
+
+/**    
+ * @} end of FIR_Lattice group    
+ */