Diff: cmsis_dsp/FilteringFunctions/arm_correlate_opt_q7.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_correlate_opt_q7.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,463 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_correlate_opt_q7.c    
+*    
+* Description:    Correlation of Q7 sequences.  
+*    
+* Target Processor: Cortex-M4/Cortex-M3
+*  
+* Version 1.1.0 2012/02/15 
+*    Updated with more optimizations, bug fixes and minor API changes.  
+* 
+* Version 1.0.11 2011/10/18  
+*    Bug Fix in conv, correlation, partial convolution.  
+* 
+* 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 Corr    
+ * @{    
+ */
+
+/**    
+ * @brief Correlation of Q7 sequences.    
+ * @param[in] *pSrcA points to the first input sequence.    
+ * @param[in] srcALen length of the first input sequence.    
+ * @param[in] *pSrcB points to the second input sequence.    
+ * @param[in] srcBLen length of the second input sequence.    
+ * @param[out] *pDst points to the location where the output result is written.  Length 2 * max(srcALen, srcBLen) - 1.    
+ * @param[in]  *pScratch1 points to scratch buffer(of type q15_t) of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2.    
+ * @param[in]  *pScratch2 points to scratch buffer (of type q15_t) of size min(srcALen, srcBLen).    
+ * @return none.    
+ *    
+ *    
+ * \par Restrictions    
+ *  If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE    
+ *    In this case input, output, scratch1 and scratch2 buffers should be aligned by 32-bit     
+ *        
+ * @details    
+ * <b>Scaling and Overflow Behavior:</b>    
+ *    
+ * \par    
+ * The function is implemented using a 32-bit internal accumulator.    
+ * Both the inputs 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.    
+ * This approach provides 17 guard bits and there is no risk of overflow as long as <code>max(srcALen, srcBLen)<131072</code>.    
+ * The 18.14 result is then truncated to 18.7 format by discarding the low 7 bits and saturated to 1.7 format.  
+ *  
+ * 
+ */
+
+
+
+void arm_correlate_opt_q7(
+  q7_t * pSrcA,
+  uint32_t srcALen,
+  q7_t * pSrcB,
+  uint32_t srcBLen,
+  q7_t * pDst,
+  q15_t * pScratch1,
+  q15_t * pScratch2)
+{
+  q7_t *pOut = pDst;                             /* output pointer                */
+  q15_t *pScr1 = pScratch1;                      /* Temporary pointer for scratch */
+  q15_t *pScr2 = pScratch2;                      /* Temporary pointer for scratch */
+  q7_t *pIn1;                                    /* inputA pointer                */
+  q7_t *pIn2;                                    /* inputB pointer                */
+  q15_t *py;                                     /* Intermediate inputB pointer   */
+  q31_t acc0, acc1, acc2, acc3;                  /* Accumulators                  */
+  uint32_t j, k = 0u, blkCnt;                    /* loop counter                  */
+  int32_t inc = 1;                               /* output pointer increment          */
+  uint32_t outBlockSize;                         /* loop counter                  */
+  q15_t x4;                                      /* Temporary input variable      */
+  uint32_t tapCnt;                               /* loop counter                  */
+  q31_t x1, x2, x3, y1;                          /* Temporary input variables     */
+
+  /* The algorithm implementation is based on the lengths of the inputs. */
+  /* srcB is always made to slide across srcA. */
+  /* So srcBLen is always considered as shorter or equal to srcALen */
+  /* But CORR(x, y) is reverse of CORR(y, x) */
+  /* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
+  /* and the destination pointer modifier, inc is set to -1 */
+  /* If srcALen > srcBLen, zero pad has to be done to srcB to make the two inputs of same length */
+  /* But to improve the performance,        
+   * we include zeroes in the output instead of zero padding either of the the inputs*/
+  /* If srcALen > srcBLen,        
+   * (srcALen - srcBLen) zeroes has to included in the starting of the output buffer */
+  /* If srcALen < srcBLen,        
+   * (srcALen - srcBLen) zeroes has to included in the ending of the output buffer */
+  if(srcALen >= srcBLen)
+  {
+    /* Initialization of inputA pointer */
+    pIn1 = (pSrcA);
+
+    /* Initialization of inputB pointer */
+    pIn2 = (pSrcB);
+
+    /* Number of output samples is calculated */
+    outBlockSize = (2u * srcALen) - 1u;
+
+    /* When srcALen > srcBLen, zero padding is done to srcB        
+     * to make their lengths equal.        
+     * Instead, (outBlockSize - (srcALen + srcBLen - 1))        
+     * number of output samples are made zero */
+    j = outBlockSize - (srcALen + (srcBLen - 1u));
+
+    /* Updating the pointer position to non zero value */
+    pOut += j;
+
+  }
+  else
+  {
+    /* Initialization of inputA pointer */
+    pIn1 = (pSrcB);
+
+    /* Initialization of inputB pointer */
+    pIn2 = (pSrcA);
+
+    /* srcBLen is always considered as shorter or equal to srcALen */
+    j = srcBLen;
+    srcBLen = srcALen;
+    srcALen = j;
+
+    /* CORR(x, y) = Reverse order(CORR(y, x)) */
+    /* Hence set the destination pointer to point to the last output sample */
+    pOut = pDst + ((srcALen + srcBLen) - 2u);
+
+    /* Destination address modifier is set to -1 */
+    inc = -1;
+
+  }
+
+
+  /* Copy (srcBLen) samples in scratch buffer */
+  k = srcBLen >> 2u;
+
+  /* First part of the processing with loop unrolling copies 4 data points at a time.       
+   ** a second loop below copies for the remaining 1 to 3 samples. */
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner */
+    x4 = (q15_t) * pIn2++;
+    *pScr2++ = x4;
+    x4 = (q15_t) * pIn2++;
+    *pScr2++ = x4;
+    x4 = (q15_t) * pIn2++;
+    *pScr2++ = x4;
+    x4 = (q15_t) * pIn2++;
+    *pScr2++ = x4;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+  /* If the count is not a multiple of 4, copy remaining samples here.       
+   ** No loop unrolling is used. */
+  k = srcBLen % 0x4u;
+
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner for remaining samples */
+    x4 = (q15_t) * pIn2++;
+    *pScr2++ = x4;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+  /* Fill (srcBLen - 1u) zeros in scratch buffer */
+  arm_fill_q15(0, pScr1, (srcBLen - 1u));
+
+  /* Update temporary scratch pointer */
+  pScr1 += (srcBLen - 1u);
+
+  /* Copy (srcALen) samples in scratch buffer */
+  k = srcALen >> 2u;
+
+  /* First part of the processing with loop unrolling copies 4 data points at a time.       
+   ** a second loop below copies for the remaining 1 to 3 samples. */
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner */
+    x4 = (q15_t) * pIn1++;
+    *pScr1++ = x4;
+    x4 = (q15_t) * pIn1++;
+    *pScr1++ = x4;
+    x4 = (q15_t) * pIn1++;
+    *pScr1++ = x4;
+    x4 = (q15_t) * pIn1++;
+    *pScr1++ = x4;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+  /* If the count is not a multiple of 4, copy remaining samples here.       
+   ** No loop unrolling is used. */
+  k = srcALen % 0x4u;
+
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner for remaining samples */
+    x4 = (q15_t) * pIn1++;
+    *pScr1++ = x4;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+  /* Fill (srcBLen - 1u) zeros at end of scratch buffer */
+  arm_fill_q15(0, pScr1, (srcBLen - 1u));
+
+  /* Update pointer */
+  pScr1 += (srcBLen - 1u);
+
+#else
+
+/* Apply loop unrolling and do 4 Copies simultaneously. */
+  k = (srcBLen - 1u) >> 2u;
+
+  /* First part of the processing with loop unrolling copies 4 data points at a time.       
+   ** a second loop below copies for the remaining 1 to 3 samples. */
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner */
+    *pScr1++ = 0;
+    *pScr1++ = 0;
+    *pScr1++ = 0;
+    *pScr1++ = 0;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+  /* If the count is not a multiple of 4, copy remaining samples here.       
+   ** No loop unrolling is used. */
+  k = (srcBLen - 1u) % 0x4u;
+
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner for remaining samples */
+    *pScr1++ = 0;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+#endif    /*    #ifndef UNALIGNED_SUPPORT_DISABLE    */
+
+  /* Temporary pointer for second sequence */
+  py = pScratch2;
+
+  /* Initialization of pScr2 pointer */
+  pScr2 = pScratch2;
+
+  /* Actual correlation process starts here */
+  blkCnt = (srcALen + srcBLen - 1u) >> 2;
+
+  while(blkCnt > 0)
+  {
+    /* Initialze temporary scratch pointer as scratch1 */
+    pScr1 = pScratch1;
+
+    /* Clear Accumlators */
+    acc0 = 0;
+    acc1 = 0;
+    acc2 = 0;
+    acc3 = 0;
+
+    /* Read two samples from scratch1 buffer */
+    x1 = *__SIMD32(pScr1)++;
+
+    /* Read next two samples from scratch1 buffer */
+    x2 = *__SIMD32(pScr1)++;
+
+    tapCnt = (srcBLen) >> 2u;
+
+    while(tapCnt > 0u)
+    {
+
+      /* Read four samples from smaller buffer */
+      y1 = _SIMD32_OFFSET(pScr2);
+
+      /* multiply and accumlate */
+      acc0 = __SMLAD(x1, y1, acc0);
+      acc2 = __SMLAD(x2, y1, acc2);
+
+      /* pack input data */
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      /* multiply and accumlate */
+      acc1 = __SMLADX(x3, y1, acc1);
+
+      /* Read next two samples from scratch1 buffer */
+      x1 = *__SIMD32(pScr1)++;
+
+      /* pack input data */
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x1, x2, 0);
+#else
+      x3 = __PKHBT(x2, x1, 0);
+#endif
+
+      acc3 = __SMLADX(x3, y1, acc3);
+
+      /* Read four samples from smaller buffer */
+      y1 = _SIMD32_OFFSET(pScr2 + 2u);
+
+      acc0 = __SMLAD(x2, y1, acc0);
+
+      acc2 = __SMLAD(x1, y1, acc2);
+
+      acc1 = __SMLADX(x3, y1, acc1);
+
+      x2 = *__SIMD32(pScr1)++;
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc3 = __SMLADX(x3, y1, acc3);
+
+      pScr2 += 4u;
+
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+
+
+    /* Update scratch pointer for remaining samples of smaller length sequence */
+    pScr1 -= 4u;
+
+
+    /* apply same above for remaining samples of smaller length sequence */
+    tapCnt = (srcBLen) & 3u;
+
+    while(tapCnt > 0u)
+    {
+
+      /* accumlate the results */
+      acc0 += (*pScr1++ * *pScr2);
+      acc1 += (*pScr1++ * *pScr2);
+      acc2 += (*pScr1++ * *pScr2);
+      acc3 += (*pScr1++ * *pScr2++);
+
+      pScr1 -= 3u;
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    blkCnt--;
+
+    /* Store the result in the accumulator in the destination buffer. */
+    *pOut = (q7_t) (__SSAT(acc0 >> 7u, 8));
+    pOut += inc;
+    *pOut = (q7_t) (__SSAT(acc1 >> 7u, 8));
+    pOut += inc;
+    *pOut = (q7_t) (__SSAT(acc2 >> 7u, 8));
+    pOut += inc;
+    *pOut = (q7_t) (__SSAT(acc3 >> 7u, 8));
+    pOut += inc;
+
+    /* Initialization of inputB pointer */
+    pScr2 = py;
+
+    pScratch1 += 4u;
+
+  }
+
+
+  blkCnt = (srcALen + srcBLen - 1u) & 0x3;
+
+  /* Calculate correlation for remaining samples of Bigger length sequence */
+  while(blkCnt > 0)
+  {
+    /* Initialze temporary scratch pointer as scratch1 */
+    pScr1 = pScratch1;
+
+    /* Clear Accumlators */
+    acc0 = 0;
+
+    tapCnt = (srcBLen) >> 1u;
+
+    while(tapCnt > 0u)
+    {
+      acc0 += (*pScr1++ * *pScr2++);
+      acc0 += (*pScr1++ * *pScr2++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    tapCnt = (srcBLen) & 1u;
+
+    /* apply same above for remaining samples of smaller length sequence */
+    while(tapCnt > 0u)
+    {
+
+      /* accumlate the results */
+      acc0 += (*pScr1++ * *pScr2++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    blkCnt--;
+
+    /* Store the result in the accumulator in the destination buffer. */
+    *pOut = (q7_t) (__SSAT(acc0 >> 7u, 8));
+
+    pOut += inc;
+
+    /* Initialization of inputB pointer */
+    pScr2 = py;
+
+    pScratch1 += 1u;
+
+  }
+
+}
+
+/**    
+ * @} end of Corr group    
+ */