Diff: FilteringFunctions/arm_fir_interpolate_q31.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FilteringFunctions/arm_fir_interpolate_q31.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,504 @@
+/*-----------------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:		arm_fir_interpolate_q31.c    
+*    
+* Description:	Q31 FIR interpolation.    
+*    
+* 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    
+ */
+
+/**    
+ * @addtogroup FIR_Interpolate    
+ * @{    
+ */
+
+/**    
+ * @brief Processing function for the Q31 FIR interpolator.    
+ * @param[in] *S        points to an instance of the Q31 FIR interpolator 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 input samples to process per call.    
+ * @return none.    
+ *    
+ * <b>Scaling and Overflow Behavior:</b>    
+ * \par    
+ * The function is implemented using an internal 64-bit accumulator.    
+ * The accumulator has a 2.62 format and maintains full precision of the intermediate multiplication results but provides only a single guard bit.    
+ * Thus, if the accumulator result overflows it wraps around rather than clip.    
+ * In order to avoid overflows completely the input signal must be scaled down by <code>1/(numTaps/L)</code>.    
+ * since <code>numTaps/L</code> additions occur per output sample.    
+ * After all multiply-accumulates are performed, the 2.62 accumulator is truncated to 1.32 format and then saturated to 1.31 format.    
+ */
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+void arm_fir_interpolate_q31(
+  const arm_fir_interpolate_instance_q31 * S,
+  q31_t * pSrc,
+  q31_t * pDst,
+  uint32_t blockSize)
+{
+  q31_t *pState = S->pState;                     /* State pointer */
+  q31_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
+  q31_t *pStateCurnt;                            /* Points to the current sample of the state */
+  q31_t *ptr1, *ptr2;                            /* Temporary pointers for state and coefficient buffers */
+  q63_t sum0;                                    /* Accumulators */
+  q31_t x0, c0;                                  /* Temporary variables to hold state and coefficient values */
+  uint32_t i, blkCnt, j;                         /* Loop counters */
+  uint16_t phaseLen = S->phaseLength, tapCnt;    /* Length of each polyphase filter component */
+
+  uint32_t blkCntN2;
+  q63_t acc0, acc1;
+  q31_t x1;
+
+  /* S->pState buffer contains previous frame (phaseLen - 1) samples */
+  /* pStateCurnt points to the location where the new input data should be written */
+  pStateCurnt = S->pState + ((q31_t) phaseLen - 1);
+
+  /* Initialise  blkCnt */
+  blkCnt = blockSize / 2;
+  blkCntN2 = blockSize - (2 * blkCnt);
+
+  /* Samples loop unrolled by 2 */
+  while(blkCnt > 0u)
+  {
+    /* Copy new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc++;
+    *pStateCurnt++ = *pSrc++;
+
+    /* Address modifier index of coefficient buffer */
+    j = 1u;
+
+    /* Loop over the Interpolation factor. */
+    i = (S->L);
+
+    while(i > 0u)
+    {
+      /* Set accumulator to zero */
+      acc0 = 0;
+      acc1 = 0;
+
+      /* Initialize state pointer */
+      ptr1 = pState;
+
+      /* Initialize coefficient pointer */
+      ptr2 = pCoeffs + (S->L - j);
+
+      /* Loop over the polyPhase length. Unroll by a factor of 4.        
+       ** Repeat until we've computed numTaps-(4*S->L) coefficients. */
+      tapCnt = phaseLen >> 2u;
+
+      x0 = *(ptr1++);
+
+      while(tapCnt > 0u)
+      {
+
+        /* Read the input sample */
+        x1 = *(ptr1++);
+
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Perform the multiply-accumulate */
+        acc0 += (q63_t) x0 *c0;
+        acc1 += (q63_t) x1 *c0;
+
+
+        /* Read the coefficient */
+        c0 = *(ptr2 + S->L);
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        acc0 += (q63_t) x1 *c0;
+        acc1 += (q63_t) x0 *c0;
+
+
+        /* Read the coefficient */
+        c0 = *(ptr2 + S->L * 2);
+
+        /* Read the input sample */
+        x1 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        acc0 += (q63_t) x0 *c0;
+        acc1 += (q63_t) x1 *c0;
+
+        /* Read the coefficient */
+        c0 = *(ptr2 + S->L * 3);
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        acc0 += (q63_t) x1 *c0;
+        acc1 += (q63_t) x0 *c0;
+
+
+        /* Upsampling is done by stuffing L-1 zeros between each sample.        
+         * So instead of multiplying zeros with coefficients,        
+         * Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += 4 * S->L;
+
+        /* Decrement the loop counter */
+        tapCnt--;
+      }
+
+      /* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */
+      tapCnt = phaseLen % 0x4u;
+
+      while(tapCnt > 0u)
+      {
+
+        /* Read the input sample */
+        x1 = *(ptr1++);
+
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Perform the multiply-accumulate */
+        acc0 += (q63_t) x0 *c0;
+        acc1 += (q63_t) x1 *c0;
+
+        /* Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* update states for next sample processing */
+        x0 = x1;
+
+        /* Decrement the loop counter */
+        tapCnt--;
+      }
+
+      /* The result is in the accumulator, store in the destination buffer. */
+      *pDst = (q31_t) (acc0 >> 31);
+      *(pDst + S->L) = (q31_t) (acc1 >> 31);
+
+
+      pDst++;
+
+      /* Increment the address modifier index of coefficient buffer */
+      j++;
+
+      /* Decrement the loop counter */
+      i--;
+    }
+
+    /* Advance the state pointer by 1        
+     * to process the next group of interpolation factor number samples */
+    pState = pState + 2;
+
+    pDst += S->L;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* If the blockSize is not a multiple of 2, compute any remaining output samples here.        
+   ** No loop unrolling is used. */
+  blkCnt = blkCntN2;
+
+  /* Loop over the blockSize. */
+  while(blkCnt > 0u)
+  {
+    /* Copy new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc++;
+
+    /* Address modifier index of coefficient buffer */
+    j = 1u;
+
+    /* Loop over the Interpolation factor. */
+    i = S->L;
+    while(i > 0u)
+    {
+      /* Set accumulator to zero */
+      sum0 = 0;
+
+      /* Initialize state pointer */
+      ptr1 = pState;
+
+      /* Initialize coefficient pointer */
+      ptr2 = pCoeffs + (S->L - j);
+
+      /* Loop over the polyPhase length. Unroll by a factor of 4.        
+       ** Repeat until we've computed numTaps-(4*S->L) coefficients. */
+      tapCnt = phaseLen >> 2;
+      while(tapCnt > 0u)
+      {
+
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Upsampling is done by stuffing L-1 zeros between each sample.        
+         * So instead of multiplying zeros with coefficients,        
+         * Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        sum0 += (q63_t) x0 *c0;
+
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        sum0 += (q63_t) x0 *c0;
+
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        sum0 += (q63_t) x0 *c0;
+
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        sum0 += (q63_t) x0 *c0;
+
+        /* Decrement the loop counter */
+        tapCnt--;
+      }
+
+      /* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */
+      tapCnt = phaseLen & 0x3u;
+
+      while(tapCnt > 0u)
+      {
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* Read the input sample */
+        x0 = *(ptr1++);
+
+        /* Perform the multiply-accumulate */
+        sum0 += (q63_t) x0 *c0;
+
+        /* Decrement the loop counter */
+        tapCnt--;
+      }
+
+      /* The result is in the accumulator, store in the destination buffer. */
+      *pDst++ = (q31_t) (sum0 >> 31);
+
+      /* Increment the address modifier index of coefficient buffer */
+      j++;
+
+      /* Decrement the loop counter */
+      i--;
+    }
+
+    /* Advance the state pointer by 1        
+     * to process the next group of interpolation factor number samples */
+    pState = pState + 1;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Processing is complete.        
+   ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer.        
+   ** This prepares the state buffer for the next function call. */
+
+  /* Points to the start of the state buffer */
+  pStateCurnt = S->pState;
+
+  tapCnt = (phaseLen - 1u) >> 2u;
+
+  /* copy data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+  tapCnt = (phaseLen - 1u) % 0x04u;
+
+  /* copy data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+}
+
+
+#else
+
+void arm_fir_interpolate_q31(
+  const arm_fir_interpolate_instance_q31 * S,
+  q31_t * pSrc,
+  q31_t * pDst,
+  uint32_t blockSize)
+{
+  q31_t *pState = S->pState;                     /* State pointer */
+  q31_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
+  q31_t *pStateCurnt;                            /* Points to the current sample of the state */
+  q31_t *ptr1, *ptr2;                            /* Temporary pointers for state and coefficient buffers */
+
+  /* Run the below code for Cortex-M0 */
+
+  q63_t sum;                                     /* Accumulator */
+  q31_t x0, c0;                                  /* Temporary variables to hold state and coefficient values */
+  uint32_t i, blkCnt;                            /* Loop counters */
+  uint16_t phaseLen = S->phaseLength, tapCnt;    /* Length of each polyphase filter component */
+
+
+  /* S->pState buffer contains previous frame (phaseLen - 1) samples */
+  /* pStateCurnt points to the location where the new input data should be written */
+  pStateCurnt = S->pState + ((q31_t) phaseLen - 1);
+
+  /* Total number of intput samples */
+  blkCnt = blockSize;
+
+  /* Loop over the blockSize. */
+  while(blkCnt > 0u)
+  {
+    /* Copy new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc++;
+
+    /* Loop over the Interpolation factor. */
+    i = S->L;
+
+    while(i > 0u)
+    {
+      /* Set accumulator to zero */
+      sum = 0;
+
+      /* Initialize state pointer */
+      ptr1 = pState;
+
+      /* Initialize coefficient pointer */
+      ptr2 = pCoeffs + (i - 1u);
+
+      tapCnt = phaseLen;
+
+      while(tapCnt > 0u)
+      {
+        /* Read the coefficient */
+        c0 = *(ptr2);
+
+        /* Increment the coefficient pointer by interpolation factor times. */
+        ptr2 += S->L;
+
+        /* Read the input sample */
+        x0 = *ptr1++;
+
+        /* Perform the multiply-accumulate */
+        sum += (q63_t) x0 *c0;
+
+        /* Decrement the loop counter */
+        tapCnt--;
+      }
+
+      /* The result is in the accumulator, store in the destination buffer. */
+      *pDst++ = (q31_t) (sum >> 31);
+
+      /* Decrement the loop counter */
+      i--;
+    }
+
+    /* Advance the state pointer by 1           
+     * to process the next group of interpolation factor number samples */
+    pState = pState + 1;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Processing is complete.         
+   ** Now copy the last phaseLen - 1 samples to the satrt of the state buffer.       
+   ** This prepares the state buffer for the next function call. */
+
+  /* Points to the start of the state buffer */
+  pStateCurnt = S->pState;
+
+  tapCnt = phaseLen - 1u;
+
+  /* copy data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+}
+
+#endif /*   #ifndef ARM_MATH_CM0_FAMILY */
+
+ /**    
+  * @} end of FIR_Interpolate group    
+  */