Diff: cmsis_dsp/FilteringFunctions/arm_conv_fast_opt_q15.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_conv_fast_opt_q15.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,538 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_conv_fast_opt_q15.c    
+*    
+* Description:    Fast Q15 Convolution.    
+*    
+* 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.    
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupFilters    
+ */
+
+/**    
+ * @addtogroup Conv    
+ * @{    
+ */
+
+/**    
+ * @brief Convolution of Q15 sequences (fast version) for Cortex-M3 and Cortex-M4.    
+ * @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 srcALen+srcBLen-1.    
+ * @param[in]  *pScratch1 points to scratch buffer of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2.   
+ * @param[in]  *pScratch2 points to scratch buffer 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    
+ *     
+ * <b>Scaling and Overflow Behavior:</b>    
+ *    
+ * \par    
+ * This fast version uses a 32-bit accumulator with 2.30 format.    
+ * The accumulator maintains full precision of the intermediate multiplication results    
+ * but provides only a single guard bit. There is no saturation on intermediate additions.    
+ * Thus, if the accumulator overflows it wraps around and distorts the result.    
+ * The input signals should be scaled down to avoid intermediate overflows.    
+ * Scale down the inputs by log2(min(srcALen, srcBLen)) (log2 is read as log to the base 2) times to avoid overflows,    
+ * as maximum of min(srcALen, srcBLen) number of additions are carried internally.    
+ * The 2.30 accumulator is right shifted by 15 bits and then saturated to 1.15 format to yield the final result.    
+ *    
+ * \par    
+ * See <code>arm_conv_q15()</code> for a slower implementation of this function which uses 64-bit accumulation to avoid wrap around distortion.    
+ */
+
+void arm_conv_fast_opt_q15(
+  q15_t * pSrcA,
+  uint32_t srcALen,
+  q15_t * pSrcB,
+  uint32_t srcBLen,
+  q15_t * pDst,
+  q15_t * pScratch1,
+  q15_t * pScratch2)
+{
+  q31_t acc0, acc1, acc2, acc3;                  /* Accumulators */
+  q31_t x1, x2, x3;                              /* Temporary variables to hold state and coefficient values */
+  q31_t y1, y2;                                  /* State variables */
+  q15_t *pOut = pDst;                            /* output pointer */
+  q15_t *pScr1 = pScratch1;                      /* Temporary pointer for scratch1 */
+  q15_t *pScr2 = pScratch2;                      /* Temporary pointer for scratch1 */
+  q15_t *pIn1;                                   /* inputA pointer */
+  q15_t *pIn2;                                   /* inputB pointer */
+  q15_t *px;                                     /* Intermediate inputA pointer  */
+  q15_t *py;                                     /* Intermediate inputB pointer  */
+  uint32_t j, k, blkCnt;                         /* loop counter */
+  uint32_t tapCnt;                               /* loop count */
+#ifdef UNALIGNED_SUPPORT_DISABLE
+
+  q15_t a, b;
+
+#endif    /*    #ifdef 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 */
+  if(srcALen >= srcBLen)
+  {
+    /* Initialization of inputA pointer */
+    pIn1 = pSrcA;
+
+    /* Initialization of inputB pointer */
+    pIn2 = pSrcB;
+  }
+  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;
+  }
+
+  /* Pointer to take end of scratch2 buffer */
+  pScr2 = pScratch2 + srcBLen - 1;
+
+  /* points to smaller length sequence */
+  px = pIn2;
+
+  /* Apply loop unrolling and do 4 Copies simultaneously. */
+  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. */
+
+  /* Copy smaller length input sequence in reverse order into second scratch buffer */
+  while(k > 0u)
+  {
+    /* copy second buffer in reversal manner */
+    *pScr2-- = *px++;
+    *pScr2-- = *px++;
+    *pScr2-- = *px++;
+    *pScr2-- = *px++;
+
+    /* 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 */
+    *pScr2-- = *px++;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+  /* Initialze temporary scratch pointer */
+  pScr1 = pScratch1;
+
+  /* Assuming scratch1 buffer is aligned by 32-bit */
+  /* Fill (srcBLen - 1u) zeros in scratch1 buffer */
+  arm_fill_q15(0, pScr1, (srcBLen - 1u));
+
+  /* Update temporary scratch pointer */
+  pScr1 += (srcBLen - 1u);
+
+  /* Copy bigger length sequence(srcALen) samples in scratch1 buffer */
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+  /* Copy (srcALen) samples in scratch buffer */
+  arm_copy_q15(pIn1, pScr1, srcALen);
+
+  /* Update pointers */
+  pScr1 += srcALen;
+
+#else
+
+  /* Apply loop unrolling and do 4 Copies simultaneously. */
+  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 */
+    *pScr1++ = *pIn1++;
+    *pScr1++ = *pIn1++;
+    *pScr1++ = *pIn1++;
+    *pScr1++ = *pIn1++;
+
+    /* 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 */
+    *pScr1++ = *pIn1++;
+
+    /* Decrement the loop counter */
+    k--;
+  }
+
+#endif    /*    #ifndef UNALIGNED_SUPPORT_DISABLE    */
+
+
+#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 scratch2 */
+  py = pScratch2;
+
+
+  /* Initialization of pIn2 pointer */
+  pIn2 = py;
+
+  /* First part of the processing with loop unrolling process 4 data points at a time.       
+   ** a second loop below process for the remaining 1 to 3 samples. */
+
+  /* Actual convolution 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)
+    {
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+      /* Read four samples from smaller buffer */
+      y1 = _SIMD32_OFFSET(pIn2);
+      y2 = _SIMD32_OFFSET(pIn2 + 2u);
+
+      /* 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_OFFSET(pScr1);
+
+      /* multiply and accumlate */
+      acc0 = __SMLAD(x2, y2, acc0);
+      acc2 = __SMLAD(x1, y2, acc2);
+
+      /* 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);
+      acc1 = __SMLADX(x3, y2, acc1);
+
+      x2 = _SIMD32_OFFSET(pScr1 + 2u);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc3 = __SMLADX(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 = __SMLAD(x1, y1, acc0);
+
+      acc2 = __SMLAD(x2, y1, acc2);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x2, x1, 0);
+#else
+      x3 = __PKHBT(x1, x2, 0);
+#endif
+
+      acc1 = __SMLADX(x3, y1, acc1);
+
+      a = *pScr1;
+      b = *(pScr1 + 1);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x1 = __PKHBT(a, b, 16);
+#else
+      x1 = __PKHBT(b, a, 16);
+#endif
+
+      acc0 = __SMLAD(x2, y2, acc0);
+
+      acc2 = __SMLAD(x1, y2, acc2);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+      x3 = __PKHBT(x1, x2, 0);
+#else
+      x3 = __PKHBT(x2, x1, 0);
+#endif
+
+      acc3 = __SMLADX(x3, y1, acc3);
+
+      acc1 = __SMLADX(x3, y2, acc1);
+
+      a = *(pScr1 + 2);
+      b = *(pScr1 + 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 = __SMLADX(x3, y2, acc3);
+
+#endif    /*    #ifndef UNALIGNED_SUPPORT_DISABLE    */
+
+      /* update scratch pointers */
+      pIn2 += 4u;
+      pScr1 += 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++ * *pIn2);
+      acc1 += (*pScr1++ * *pIn2);
+      acc2 += (*pScr1++ * *pIn2);
+      acc3 += (*pScr1++ * *pIn2++);
+
+      pScr1 -= 3u;
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    blkCnt--;
+
+
+    /* Store the results in the accumulators in the destination buffer. */
+
+#ifndef ARM_MATH_BIG_ENDIAN
+
+    *__SIMD32(pOut)++ =
+      __PKHBT(__SSAT((acc0 >> 15), 16), __SSAT((acc1 >> 15), 16), 16);
+
+    *__SIMD32(pOut)++ =
+      __PKHBT(__SSAT((acc2 >> 15), 16), __SSAT((acc3 >> 15), 16), 16);
+
+
+#else
+
+    *__SIMD32(pOut)++ =
+      __PKHBT(__SSAT((acc1 >> 15), 16), __SSAT((acc0 >> 15), 16), 16);
+
+    *__SIMD32(pOut)++ =
+      __PKHBT(__SSAT((acc3 >> 15), 16), __SSAT((acc2 >> 15), 16), 16);
+
+
+
+#endif /*      #ifndef ARM_MATH_BIG_ENDIAN       */
+
+    /* Initialization of inputB pointer */
+    pIn2 = py;
+
+    pScratch1 += 4u;
+
+  }
+
+
+  blkCnt = (srcALen + srcBLen - 1u) & 0x3;
+
+  /* Calculate convolution 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++ * *pIn2++);
+      acc0 += (*pScr1++ * *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 += (*pScr1++ * *pIn2++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    blkCnt--;
+
+    /* The result is in 2.30 format.  Convert to 1.15 with saturation.       
+     ** Then store the output in the destination buffer. */
+    *pOut++ = (q15_t) (__SSAT((acc0 >> 15), 16));
+
+    /* Initialization of inputB pointer */
+    pIn2 = py;
+
+    pScratch1 += 1u;
+
+  }
+
+}
+
+/**    
+ * @} end of Conv group    
+ */