Diff: cmsis_dsp/FilteringFunctions/arm_fir_interpolate_q15.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_fir_interpolate_q15.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,503 @@
+/*-----------------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_fir_interpolate_q15.c    
+*    
+* Description:    Q15 FIR interpolation.    
+*    
+* 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_Interpolate    
+ * @{    
+ */
+
+/**    
+ * @brief Processing function for the Q15 FIR interpolator.    
+ * @param[in] *S        points to an instance of the Q15 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 a 64-bit internal accumulator.    
+ * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result.    
+ * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format.    
+ * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved.    
+ * After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits.    
+ * Lastly, the accumulator is saturated to yield a result in 1.15 format.    
+ */
+
+#ifndef ARM_MATH_CM0
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+void arm_fir_interpolate_q15(
+  const arm_fir_interpolate_instance_q15 * S,
+  q15_t * pSrc,
+  q15_t * pDst,
+  uint32_t blockSize)
+{
+  q15_t *pState = S->pState;                     /* State pointer                                            */
+  q15_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer                                      */
+  q15_t *pStateCurnt;                            /* Points to the current sample of the state                */
+  q15_t *ptr1, *ptr2;                            /* Temporary pointers for state and coefficient buffers     */
+  q63_t sum0;                                    /* Accumulators                                             */
+  q15_t x0, c0;                                  /* Temporary variables to hold state and coefficient values */
+  uint32_t i, blkCnt, j, tapCnt;                 /* Loop counters                                            */
+  uint16_t phaseLen = S->phaseLength;            /* Length of each polyphase filter component */
+  uint32_t blkCntN2;
+  q63_t acc0, acc1;
+  q15_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 = (q15_t) (__SSAT((acc0 >> 15), 16));
+      *(pDst + S->L) = (q15_t) (__SSAT((acc1 >> 15), 16));
+
+      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++ = (q15_t) (__SSAT((sum0 >> 15), 16));
+
+      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;
+
+  i = ((uint32_t) phaseLen - 1u) >> 2u;
+
+  /* copy data */
+  while(i > 0u)
+  {
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+    *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
+    *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
+
+#else
+
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    
+#endif    /*    #ifndef UNALIGNED_SUPPORT_DISABLE    */
+    
+    /* Decrement the loop counter */
+    i--;
+  }
+
+  i = ((uint32_t) phaseLen - 1u) % 0x04u;
+
+  while(i > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    i--;
+  }
+}
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+void arm_fir_interpolate_q15(
+  const arm_fir_interpolate_instance_q15 * S,
+  q15_t * pSrc,
+  q15_t * pDst,
+  uint32_t blockSize)
+{
+  q15_t *pState = S->pState;                     /* State pointer                                            */
+  q15_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer                                      */
+  q15_t *pStateCurnt;                            /* Points to the current sample of the state                */
+  q15_t *ptr1, *ptr2;                            /* Temporary pointers for state and coefficient buffers     */
+  q63_t sum;                                     /* Accumulator */
+  q15_t x0, c0;                                  /* Temporary variables to hold state and coefficient values */
+  uint32_t i, blkCnt, tapCnt;                    /* Loop counters                                            */
+  uint16_t phaseLen = S->phaseLength;            /* 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 + (phaseLen - 1u);
+
+  /* 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);
+
+      /* Loop over the polyPhase length */
+      tapCnt = (uint32_t) 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 += ((q31_t) x0 * c0);
+
+        /* Decrement the loop counter */
+        tapCnt--;
+      }
+
+      /* Store the result after converting to 1.15 format in the destination buffer */
+      *pDst++ = (q15_t) (__SSAT((sum >> 15), 16));
+
+      /* 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 start 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;
+
+  i = (uint32_t) phaseLen - 1u;
+
+  while(i > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    i--;
+  }
+
+}
+
+#endif /*   #ifndef ARM_MATH_CM0 */
+
+
+ /**    
+  * @} end of FIR_Interpolate group    
+  */