Diff: cmsis_dsp/FilteringFunctions/arm_fir_lattice_q15.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_fir_lattice_q15.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,531 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* 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 1.1.0 2012/02/15 
+*    Updated with more optimizations, bug fixes and minor API changes.  
+*   
+* 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);
+
+      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 g4(n) in state buffer */
+      *px++ = (q15_t) gnext4;
+
+      /* Sample processing for K5, K9.... */
+      /* Process first sample for 5th, 9th .. tap */
+      /* f5(n) = f4(n) +  K5 * g4(n-1) */
+      fcurnt1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fnext1;
+      fcurnt1 = __SSAT(fcurnt1, 16);
+
+      /* Process second sample for 5th, 9th .. tap */
+      fcurnt2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fnext2;
+      fcurnt2 = __SSAT(fcurnt2, 16);
+
+      /* Process third sample for 5th, 9th .. tap */
+      fcurnt3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fnext3;
+      fcurnt3 = __SSAT(fcurnt3, 16);
+
+      /* Process fourth sample for 5th, 9th .. tap */
+      fcurnt4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fnext4;
+      fcurnt4 = __SSAT(fcurnt4, 16);
+
+      /* Calculation of state values for next stage */
+      /* g5(n) = f4(n) * K5  +  g4(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);
+
+      stageCnt--;
+    }
+
+    /* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */
+    stageCnt = (numStages - 1u) % 0x4u;
+
+    while(stageCnt > 0u)
+    {
+      gcurnt1 = *px;
+
+      /* save g value in state buffer */
+      *px++ = (q15_t) gnext4;
+
+      /* Process four samples for last three taps here */
+      fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1;
+      fnext1 = __SSAT(fnext1, 16);
+      fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2;
+      fnext2 = __SSAT(fnext2, 16);
+
+      fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3;
+      fnext3 = __SSAT(fnext3, 16);
+
+      fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4;
+      fnext4 = __SSAT(fnext4, 16);
+
+      /* g1(n) = f0(n) * K1  +  g0(n-1) */
+      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);
+
+      /* Update of f values for next coefficient set processing */
+      fcurnt1 = fnext1;
+      fcurnt2 = fnext2;
+      fcurnt3 = fnext3;
+      fcurnt4 = fnext4;
+
+      stageCnt--;
+
+    }
+
+    /* The results in the 4 accumulators, store in the destination buffer. */
+    /* y(n) = fN(n) */
+
+#ifndef  ARM_MATH_BIG_ENDIAN
+
+    *__SIMD32(pDst)++ = __PKHBT(fcurnt1, fcurnt2, 16);
+    *__SIMD32(pDst)++ = __PKHBT(fcurnt3, fcurnt4, 16);
+
+#else
+
+    *__SIMD32(pDst)++ = __PKHBT(fcurnt2, fcurnt1, 16);
+    *__SIMD32(pDst)++ = __PKHBT(fcurnt4, fcurnt3, 16);
+
+#endif /*      #ifndef  ARM_MATH_BIG_ENDIAN    */
+
+    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) */
+    fcurnt1 = *pSrc++;
+
+    /* Initialize coeff pointer */
+    pk = (pCoeffs);
+
+    /* Initialize state pointer */
+    px = pState;
+
+    /* read g2(n) from state buffer */
+    gcurnt1 = *px;
+
+    /* for sample 1 processing */
+    /* 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);
+
+    /* save g1(n) in state buffer */
+    *px++ = (q15_t) fcurnt1;
+
+    /* f1(n) is saved in fcurnt1    
+       for next stage processing */
+    fcurnt1 = fnext1;
+
+    stageCnt = (numStages - 1u);
+
+    /* stage loop */
+    while(stageCnt > 0u)
+    {
+      /* read g2(n) from state buffer */
+      gcurnt1 = *px;
+
+      /* save g1(n) in state buffer */
+      *px++ = (q15_t) gnext1;
+
+      /* Sample processing for K2, K3.... */
+      /* f2(n) = f1(n) +  K2 * g1(n-1) */
+      fnext1 = (((q31_t) gcurnt1 * (*pk)) >> 15u) + fcurnt1;
+      fnext1 = __SSAT(fnext1, 16);
+
+      /* g2(n) = f1(n) * K2  +  g1(n-1) */
+      gnext1 = (((q31_t) fcurnt1 * (*pk++)) >> 15u) + gcurnt1;
+      gnext1 = __SSAT(gnext1, 16);
+
+
+      /* f1(n) is saved in fcurnt1    
+         for next stage processing */
+      fcurnt1 = fnext1;
+
+      stageCnt--;
+
+    }
+
+    /* y(n) = fN(n) */
+    *pDst++ = __SSAT(fcurnt1, 16);
+
+
+    blkCnt--;
+
+  }
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  q31_t fcurnt, fnext, gcurnt, 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) */
+    fcurnt = *pSrc++;
+
+    /* Initialize coeff pointer */
+    pk = (pCoeffs);
+
+    /* Initialize state pointer */
+    px = pState;
+
+    /* read g0(n-1) from state buffer */
+    gcurnt = *px;
+
+    /* for sample 1 processing */
+    /* f1(n) = f0(n) +  K1 * g0(n-1) */
+    fnext = ((gcurnt * (*pk)) >> 15u) + fcurnt;
+    fnext = __SSAT(fnext, 16);
+
+
+    /* g1(n) = f0(n) * K1  +  g0(n-1) */
+    gnext = ((fcurnt * (*pk++)) >> 15u) + gcurnt;
+    gnext = __SSAT(gnext, 16);
+
+    /* save f0(n) in state buffer */
+    *px++ = (q15_t) fcurnt;
+
+    /* f1(n) is saved in fcurnt            
+       for next stage processing */
+    fcurnt = fnext;
+
+    stageCnt = (numStages - 1u);
+
+    /* stage loop */
+    while(stageCnt > 0u)
+    {
+      /* read g1(n-1) from state buffer */
+      gcurnt = *px;
+
+      /* save g0(n-1) in state buffer */
+      *px++ = (q15_t) gnext;
+
+      /* Sample processing for K2, K3.... */
+      /* f2(n) = f1(n) +  K2 * g1(n-1) */
+      fnext = ((gcurnt * (*pk)) >> 15u) + fcurnt;
+      fnext = __SSAT(fnext, 16);
+
+      /* g2(n) = f1(n) * K2  +  g1(n-1) */
+      gnext = ((fcurnt * (*pk++)) >> 15u) + gcurnt;
+      gnext = __SSAT(gnext, 16);
+
+
+      /* f1(n) is saved in fcurnt            
+         for next stage processing */
+      fcurnt = fnext;
+
+      stageCnt--;
+
+    }
+
+    /* y(n) = fN(n) */
+    *pDst++ = __SSAT(fcurnt, 16);
+
+
+    blkCnt--;
+
+  }
+
+#endif /*   #ifndef ARM_MATH_CM0 */
+
+}
+
+/**    
+ * @} end of FIR_Lattice group    
+ */