Diff: cmsis_dsp/FilteringFunctions/arm_fir_sparse_q7.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_fir_sparse_q7.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,398 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_fir_sparse_q7.c    
+*    
+* Description:    Q7 sparse FIR 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_Sparse    
+ * @{    
+ */
+
+
+/**   
+ * @brief Processing function for the Q7 sparse FIR filter.   
+ * @param[in]  *S           points to an instance of the Q7 sparse FIR structure.   
+ * @param[in]  *pSrc        points to the block of input data.   
+ * @param[out] *pDst        points to the block of output data   
+ * @param[in]  *pScratchIn  points to a temporary buffer of size blockSize.   
+ * @param[in]  *pScratchOut points to a temporary buffer of size blockSize.   
+ * @param[in]  blockSize    number of input samples to process per call.   
+ * @return none.   
+ *    
+ * <b>Scaling and Overflow Behavior:</b>    
+ * \par    
+ * The function is implemented using a 32-bit internal accumulator.    
+ * Both coefficients and state variables are represented in 1.7 format and multiplications yield a 2.14 result.    
+ * The 2.14 intermediate results are accumulated in a 32-bit accumulator in 18.14 format.    
+ * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved.    
+ * The accumulator is then converted to 18.7 format by discarding the low 7 bits.   
+ * Finally, the result is truncated to 1.7 format.   
+ */
+
+void arm_fir_sparse_q7(
+  arm_fir_sparse_instance_q7 * S,
+  q7_t * pSrc,
+  q7_t * pDst,
+  q7_t * pScratchIn,
+  q31_t * pScratchOut,
+  uint32_t blockSize)
+{
+
+  q7_t *pState = S->pState;                      /* State pointer */
+  q7_t *pCoeffs = S->pCoeffs;                    /* Coefficient pointer */
+  q7_t *px;                                      /* Scratch buffer pointer */
+  q7_t *py = pState;                             /* Temporary pointers for state buffer */
+  q7_t *pb = pScratchIn;                         /* Temporary pointers for scratch buffer */
+  q7_t *pOut = pDst;                             /* Destination pointer */
+  int32_t *pTapDelay = S->pTapDelay;             /* Pointer to the array containing offset of the non-zero tap values. */
+  uint32_t delaySize = S->maxDelay + blockSize;  /* state length */
+  uint16_t numTaps = S->numTaps;                 /* Filter order */
+  int32_t readIndex;                             /* Read index of the state buffer */
+  uint32_t tapCnt, blkCnt;                       /* loop counters */
+  q7_t coeff = *pCoeffs++;                       /* Read the coefficient value */
+  q31_t *pScr2 = pScratchOut;                    /* Working pointer for scratch buffer of output values */
+  q31_t in;
+
+
+#ifndef ARM_MATH_CM0
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  q7_t in1, in2, in3, in4;
+
+  /* BlockSize of Input samples are copied into the state buffer */
+  /* StateIndex points to the starting position to write in the state buffer */
+  arm_circularWrite_q7(py, (int32_t) delaySize, &S->stateIndex, 1, pSrc, 1,
+                       blockSize);
+
+  /* Loop over the number of taps. */
+  tapCnt = numTaps;
+
+  /* Read Index, from where the state buffer should be read, is calculated. */
+  readIndex = ((int32_t) S->stateIndex - (int32_t) blockSize) - *pTapDelay++;
+
+  /* Wraparound of readIndex */
+  if(readIndex < 0)
+  {
+    readIndex += (int32_t) delaySize;
+  }
+
+  /* Working pointer for state buffer is updated */
+  py = pState;
+
+  /* blockSize samples are read from the state buffer */
+  arm_circularRead_q7(py, (int32_t) delaySize, &readIndex, 1, pb, pb,
+                      (int32_t) blockSize, 1, blockSize);
+
+  /* Working pointer for the scratch buffer of state values */
+  px = pb;
+
+  /* Working pointer for scratch buffer of output values */
+  pScratchOut = pScr2;
+
+  /* Loop over the blockSize. Unroll by a factor of 4.    
+   * Compute 4 multiplications at a time. */
+  blkCnt = blockSize >> 2;
+
+  while(blkCnt > 0u)
+  {
+    /* Perform multiplication and store in the scratch buffer */
+    *pScratchOut++ = ((q31_t) * px++ * coeff);
+    *pScratchOut++ = ((q31_t) * px++ * coeff);
+    *pScratchOut++ = ((q31_t) * px++ * coeff);
+    *pScratchOut++ = ((q31_t) * px++ * coeff);
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* If the blockSize is not a multiple of 4,    
+   * compute the remaining samples */
+  blkCnt = blockSize % 0x4u;
+
+  while(blkCnt > 0u)
+  {
+    /* Perform multiplication and store in the scratch buffer */
+    *pScratchOut++ = ((q31_t) * px++ * coeff);
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Load the coefficient value and    
+   * increment the coefficient buffer for the next set of state values */
+  coeff = *pCoeffs++;
+
+  /* Read Index, from where the state buffer should be read, is calculated. */
+  readIndex = ((int32_t) S->stateIndex - (int32_t) blockSize) - *pTapDelay++;
+
+  /* Wraparound of readIndex */
+  if(readIndex < 0)
+  {
+    readIndex += (int32_t) delaySize;
+  }
+
+  /* Loop over the number of taps. */
+  tapCnt = (uint32_t) numTaps - 1u;
+
+  while(tapCnt > 0u)
+  {
+    /* Working pointer for state buffer is updated */
+    py = pState;
+
+    /* blockSize samples are read from the state buffer */
+    arm_circularRead_q7(py, (int32_t) delaySize, &readIndex, 1, pb, pb,
+                        (int32_t) blockSize, 1, blockSize);
+
+    /* Working pointer for the scratch buffer of state values */
+    px = pb;
+
+    /* Working pointer for scratch buffer of output values */
+    pScratchOut = pScr2;
+
+    /* Loop over the blockSize. Unroll by a factor of 4.    
+     * Compute 4 MACS at a time. */
+    blkCnt = blockSize >> 2;
+
+    while(blkCnt > 0u)
+    {
+      /* Perform Multiply-Accumulate */
+      in = *pScratchOut + ((q31_t) * px++ * coeff);
+      *pScratchOut++ = in;
+      in = *pScratchOut + ((q31_t) * px++ * coeff);
+      *pScratchOut++ = in;
+      in = *pScratchOut + ((q31_t) * px++ * coeff);
+      *pScratchOut++ = in;
+      in = *pScratchOut + ((q31_t) * px++ * coeff);
+      *pScratchOut++ = in;
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+
+    /* If the blockSize is not a multiple of 4,    
+     * compute the remaining samples */
+    blkCnt = blockSize % 0x4u;
+
+    while(blkCnt > 0u)
+    {
+      /* Perform Multiply-Accumulate */
+      in = *pScratchOut + ((q31_t) * px++ * coeff);
+      *pScratchOut++ = in;
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+
+    /* Load the coefficient value and    
+     * increment the coefficient buffer for the next set of state values */
+    coeff = *pCoeffs++;
+
+    /* Read Index, from where the state buffer should be read, is calculated. */
+    readIndex = ((int32_t) S->stateIndex -
+                 (int32_t) blockSize) - *pTapDelay++;
+
+    /* Wraparound of readIndex */
+    if(readIndex < 0)
+    {
+      readIndex += (int32_t) delaySize;
+    }
+
+    /* Decrement the tap loop counter */
+    tapCnt--;
+  }
+
+  /* All the output values are in pScratchOut buffer.    
+     Convert them into 1.15 format, saturate and store in the destination buffer. */
+  /* Loop over the blockSize. */
+  blkCnt = blockSize >> 2;
+
+  while(blkCnt > 0u)
+  {
+    in1 = (q7_t) __SSAT(*pScr2++ >> 7, 8);
+    in2 = (q7_t) __SSAT(*pScr2++ >> 7, 8);
+    in3 = (q7_t) __SSAT(*pScr2++ >> 7, 8);
+    in4 = (q7_t) __SSAT(*pScr2++ >> 7, 8);
+
+    *__SIMD32(pOut)++ = __PACKq7(in1, in2, in3, in4);
+
+    /* Decrement the blockSize loop counter */
+    blkCnt--;
+  }
+
+  /* If the blockSize is not a multiple of 4,    
+     remaining samples are processed in the below loop */
+  blkCnt = blockSize % 0x4u;
+
+  while(blkCnt > 0u)
+  {
+    *pOut++ = (q7_t) __SSAT(*pScr2++ >> 7, 8);
+
+    /* Decrement the blockSize loop counter */
+    blkCnt--;
+  }
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* BlockSize of Input samples are copied into the state buffer */
+  /* StateIndex points to the starting position to write in the state buffer */
+  arm_circularWrite_q7(py, (int32_t) delaySize, &S->stateIndex, 1, pSrc, 1,
+                       blockSize);
+
+  /* Loop over the number of taps. */
+  tapCnt = numTaps;
+
+  /* Read Index, from where the state buffer should be read, is calculated. */
+  readIndex = ((int32_t) S->stateIndex - (int32_t) blockSize) - *pTapDelay++;
+
+  /* Wraparound of readIndex */
+  if(readIndex < 0)
+  {
+    readIndex += (int32_t) delaySize;
+  }
+
+  /* Working pointer for state buffer is updated */
+  py = pState;
+
+  /* blockSize samples are read from the state buffer */
+  arm_circularRead_q7(py, (int32_t) delaySize, &readIndex, 1, pb, pb,
+                      (int32_t) blockSize, 1, blockSize);
+
+  /* Working pointer for the scratch buffer of state values */
+  px = pb;
+
+  /* Working pointer for scratch buffer of output values */
+  pScratchOut = pScr2;
+
+  /* Loop over the blockSize */
+  blkCnt = blockSize;
+
+  while(blkCnt > 0u)
+  {
+    /* Perform multiplication and store in the scratch buffer */
+    *pScratchOut++ = ((q31_t) * px++ * coeff);
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Load the coefficient value and           
+   * increment the coefficient buffer for the next set of state values */
+  coeff = *pCoeffs++;
+
+  /* Read Index, from where the state buffer should be read, is calculated. */
+  readIndex = ((int32_t) S->stateIndex - (int32_t) blockSize) - *pTapDelay++;
+
+  /* Wraparound of readIndex */
+  if(readIndex < 0)
+  {
+    readIndex += (int32_t) delaySize;
+  }
+
+  /* Loop over the number of taps. */
+  tapCnt = (uint32_t) numTaps - 1u;
+
+  while(tapCnt > 0u)
+  {
+    /* Working pointer for state buffer is updated */
+    py = pState;
+
+    /* blockSize samples are read from the state buffer */
+    arm_circularRead_q7(py, (int32_t) delaySize, &readIndex, 1, pb, pb,
+                        (int32_t) blockSize, 1, blockSize);
+
+    /* Working pointer for the scratch buffer of state values */
+    px = pb;
+
+    /* Working pointer for scratch buffer of output values */
+    pScratchOut = pScr2;
+
+    /* Loop over the blockSize */
+    blkCnt = blockSize;
+
+    while(blkCnt > 0u)
+    {
+      /* Perform Multiply-Accumulate */
+      in = *pScratchOut + ((q31_t) * px++ * coeff);
+      *pScratchOut++ = in;
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+
+    /* Load the coefficient value and           
+     * increment the coefficient buffer for the next set of state values */
+    coeff = *pCoeffs++;
+
+    /* Read Index, from where the state buffer should be read, is calculated. */
+    readIndex =
+      ((int32_t) S->stateIndex - (int32_t) blockSize) - *pTapDelay++;
+
+    /* Wraparound of readIndex */
+    if(readIndex < 0)
+    {
+      readIndex += (int32_t) delaySize;
+    }
+
+    /* Decrement the tap loop counter */
+    tapCnt--;
+  }
+
+  /* All the output values are in pScratchOut buffer.       
+     Convert them into 1.15 format, saturate and store in the destination buffer. */
+  /* Loop over the blockSize. */
+  blkCnt = blockSize;
+
+  while(blkCnt > 0u)
+  {
+    *pOut++ = (q7_t) __SSAT(*pScr2++ >> 7, 8);
+
+    /* Decrement the blockSize loop counter */
+    blkCnt--;
+  }
+
+#endif /*   #ifndef ARM_MATH_CM0 */
+
+}
+
+/**    
+ * @} end of FIR_Sparse group    
+ */