Diff: FilteringFunctions/arm_correlate_opt_q15.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FilteringFunctions/arm_correlate_opt_q15.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,513 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:		arm_correlate_opt_q15.c    
+*    
+* Description:	Correlation of Q15 sequences.  
+*    
+* Target Processor: Cortex-M4/Cortex-M3
+*  
+* 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 Corr    
+ * @{    
+ */
+
+/**    
+ * @brief Correlation of Q15 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]  *pScratch points to scratch buffer of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2.    
+ * @return none.    
+ *    
+ * \par Restrictions    
+ *  If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE    
+ *	In this case input, output, scratch buffers should be aligned by 32-bit    
+ *     
+ * @details    
+ * <b>Scaling and Overflow Behavior:</b>    
+ *    
+ * \par    
+ * The function is implemented using a 64-bit internal accumulator.    
+ * Both inputs are 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.    
+ * This approach provides 33 guard bits and there is no risk of overflow.    
+ * The 34.30 result is then truncated to 34.15 format by discarding the low 15 bits and then saturated to 1.15 format.    
+ *    
+ * \par    
+ * Refer to <code>arm_correlate_fast_q15()</code> for a faster but less precise version of this function for Cortex-M3 and Cortex-M4.   
+ *  
+ * 
+ */
+
+
+void arm_correlate_opt_q15(
+  q15_t * pSrcA,
+  uint32_t srcALen,
+  q15_t * pSrcB,
+  uint32_t srcBLen,
+  q15_t * pDst,
+  q15_t * pScratch)
+{
+  q15_t *pIn1;                                   /* inputA pointer               */
+  q15_t *pIn2;                                   /* inputB pointer               */
+  q63_t acc0, acc1, acc2, acc3;                  /* Accumulators                  */
+  q15_t *py;                                     /* Intermediate inputB pointer  */
+  q31_t x1, x2, x3;                              /* temporary variables for holding input1 and input2 values */
+  uint32_t j, blkCnt, outBlockSize;              /* loop counter                 */
+  int32_t inc = 1;                               /* output pointer increment     */
+  uint32_t tapCnt;
+  q31_t y1, y2;
+  q15_t *pScr;                                   /* Intermediate pointers        */
+  q15_t *pOut = pDst;                            /* output pointer               */
+#ifdef UNALIGNED_SUPPORT_DISABLE
+
+  q15_t a, b;
+
+#endif	/*	#ifndef UNALIGNED_SUPPORT_DISABLE	*/
+
+  /* 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;
+
+  }
+
+  pScr = pScratch;
+
+  /* Fill (srcBLen - 1u) zeros in scratch buffer */
+  arm_fill_q15(0, pScr, (srcBLen - 1u));
+
+  /* Update temporary scratch pointer */
+  pScr += (srcBLen - 1u);
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+  /* Copy (srcALen) samples in scratch buffer */
+  arm_copy_q15(pIn1, pScr, srcALen);
+
+  /* Update pointers */
+  //pIn1 += srcALen;    
+  pScr += srcALen;
+
+#else
+
+  /* Apply loop unrolling and do 4 Copies simultaneously. */
+  j = 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(j > 0u)
+  {
+    /* copy second buffer in reversal manner */
+    *pScr++ = *pIn1++;
+    *pScr++ = *pIn1++;
+    *pScr++ = *pIn1++;
+    *pScr++ = *pIn1++;
+
+    /* Decrement the loop counter */
+    j--;
+  }
+
+  /* If the count is not a multiple of 4, copy remaining samples here.       
+   ** No loop unrolling is used. */
+  j = srcALen % 0x4u;
+
+  while(j > 0u)
+  {
+    /* copy second buffer in reversal manner for remaining samples */
+    *pScr++ = *pIn1++;
+
+    /* Decrement the loop counter */
+    j--;
+  }
+
+#endif	/*	#ifndef UNALIGNED_SUPPORT_DISABLE	*/
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+  /* Fill (srcBLen - 1u) zeros at end of scratch buffer */
+  arm_fill_q15(0, pScr, (srcBLen - 1u));
+
+  /* Update pointer */
+  pScr += (srcBLen - 1u);
+
+#else
+
+/* Apply loop unrolling and do 4 Copies simultaneously. */
+  j = (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(j > 0u)
+  {
+    /* copy second buffer in reversal manner */
+    *pScr++ = 0;
+    *pScr++ = 0;
+    *pScr++ = 0;
+    *pScr++ = 0;
+
+    /* Decrement the loop counter */
+    j--;
+  }
+
+  /* If the count is not a multiple of 4, copy remaining samples here.       
+   ** No loop unrolling is used. */
+  j = (srcBLen - 1u) % 0x4u;
+
+  while(j > 0u)
+  {
+    /* copy second buffer in reversal manner for remaining samples */
+    *pScr++ = 0;
+
+    /* Decrement the loop counter */
+    j--;
+  }
+
+#endif	/*	#ifndef UNALIGNED_SUPPORT_DISABLE	*/
+
+  /* Temporary pointer for scratch2 */
+  py = pIn2;
+
+
+  /* Actual correlation process starts here */
+  blkCnt = (srcALen + srcBLen - 1u) >> 2;
+
+  while(blkCnt > 0)
+  {
+    /* Initialze temporary scratch pointer as scratch1 */
+    pScr = pScratch;
+
+    /* Clear Accumlators */
+    acc0 = 0;
+    acc1 = 0;
+    acc2 = 0;
+    acc3 = 0;
+
+    /* Read four samples from scratch1 buffer */
+    x1 = *__SIMD32(pScr)++;
+
+    /* Read next four samples from scratch1 buffer */
+    x2 = *__SIMD32(pScr)++;
+
+    tapCnt = (srcBLen) >> 2u;
+
+    while(tapCnt > 0u)
+    {
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+      /* Read four samples from smaller buffer */
+      y1 = _SIMD32_OFFSET(pIn2);
+      y2 = _SIMD32_OFFSET(pIn2 + 2u);
+
+      acc0 = __SMLALD(x1, y1, acc0);
+
+      acc2 = __SMLALD(x2, y1, acc2);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc1 = __SMLALDX(x3, y1, acc1);
+
+      x1 = _SIMD32_OFFSET(pScr);
+
+      acc0 = __SMLALD(x2, y2, acc0);
+
+      acc2 = __SMLALD(x1, y2, acc2);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x1, x2, 0);
+#else
+      x3 = __PKHBT(x2, x1, 0);
+#endif
+
+      acc3 = __SMLALDX(x3, y1, acc3);
+
+      acc1 = __SMLALDX(x3, y2, acc1);
+
+      x2 = _SIMD32_OFFSET(pScr + 2u);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc3 = __SMLALDX(x3, y2, acc3);
+
+#else	 
+
+      /* Read four samples from smaller buffer */
+	  a = *pIn2;
+	  b = *(pIn2 + 1);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      y1 = __PKHBT(a, b, 16);
+#else
+      y1 = __PKHBT(b, a, 16);
+#endif
+	  
+	  a = *(pIn2 + 2);
+	  b = *(pIn2 + 3);
+#ifndef ARM_MATH_BIG_ENDIAN
+      y2 = __PKHBT(a, b, 16);
+#else
+      y2 = __PKHBT(b, a, 16);
+#endif				
+
+      acc0 = __SMLALD(x1, y1, acc0);
+
+      acc2 = __SMLALD(x2, y1, acc2);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc1 = __SMLALDX(x3, y1, acc1);
+
+	  a = *pScr;
+	  b = *(pScr + 1);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x1 = __PKHBT(a, b, 16);
+#else
+      x1 = __PKHBT(b, a, 16);
+#endif
+
+      acc0 = __SMLALD(x2, y2, acc0);
+
+      acc2 = __SMLALD(x1, y2, acc2);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x1, x2, 0);
+#else
+      x3 = __PKHBT(x2, x1, 0);
+#endif
+
+      acc3 = __SMLALDX(x3, y1, acc3);
+
+      acc1 = __SMLALDX(x3, y2, acc1);
+
+	  a = *(pScr + 2);
+	  b = *(pScr + 3);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x2 = __PKHBT(a, b, 16);
+#else
+      x2 = __PKHBT(b, a, 16);
+#endif
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc3 = __SMLALDX(x3, y2, acc3);
+
+#endif	/*	#ifndef UNALIGNED_SUPPORT_DISABLE	*/
+
+      pIn2 += 4u;
+
+      pScr += 4u;
+
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+
+
+    /* Update scratch pointer for remaining samples of smaller length sequence */
+    pScr -= 4u;
+
+
+    /* apply same above for remaining samples of smaller length sequence */
+    tapCnt = (srcBLen) & 3u;
+
+    while(tapCnt > 0u)
+    {
+
+      /* accumlate the results */
+      acc0 += (*pScr++ * *pIn2);
+      acc1 += (*pScr++ * *pIn2);
+      acc2 += (*pScr++ * *pIn2);
+      acc3 += (*pScr++ * *pIn2++);
+
+      pScr -= 3u;
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    blkCnt--;
+
+
+    /* Store the results in the accumulators in the destination buffer. */
+    *pOut = (__SSAT(acc0 >> 15u, 16));
+    pOut += inc;
+    *pOut = (__SSAT(acc1 >> 15u, 16));
+    pOut += inc;
+    *pOut = (__SSAT(acc2 >> 15u, 16));
+    pOut += inc;
+    *pOut = (__SSAT(acc3 >> 15u, 16));
+    pOut += inc;
+
+    /* Initialization of inputB pointer */
+    pIn2 = py;
+
+    pScratch += 4u;
+
+  }
+
+
+  blkCnt = (srcALen + srcBLen - 1u) & 0x3;
+
+  /* Calculate correlation for remaining samples of Bigger length sequence */
+  while(blkCnt > 0)
+  {
+    /* Initialze temporary scratch pointer as scratch1 */
+    pScr = pScratch;
+
+    /* Clear Accumlators */
+    acc0 = 0;
+
+    tapCnt = (srcBLen) >> 1u;
+
+    while(tapCnt > 0u)
+    {
+
+      acc0 += (*pScr++ * *pIn2++);
+      acc0 += (*pScr++ * *pIn2++);
+
+      /* 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 += (*pScr++ * *pIn2++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    blkCnt--;
+
+    /* Store the result in the accumulator in the destination buffer. */
+    *pOut = (q15_t) (__SSAT((acc0 >> 15), 16));
+
+    pOut += inc;
+
+    /* Initialization of inputB pointer */
+    pIn2 = py;
+
+    pScratch += 1u;
+
+  }
+
+
+}
+
+/**    
+ * @} end of Corr group    
+ */