Diff: BasicMathFunctions/arm_shift_q15.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BasicMathFunctions/arm_shift_q15.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,248 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:		arm_shift_q15.c    
+*    
+* Description:	Shifts the elements of a Q15 vector by a specified number of bits.    
+*    
+* 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 groupMath    
+ */
+
+/**    
+ * @addtogroup shift    
+ * @{    
+ */
+
+/**    
+ * @brief  Shifts the elements of a Q15 vector a specified number of bits.    
+ * @param[in]  *pSrc points to the input vector    
+ * @param[in]  shiftBits number of bits to shift.  A positive value shifts left; a negative value shifts right.    
+ * @param[out]  *pDst points to the output vector    
+ * @param[in]  blockSize number of samples in the vector    
+ * @return none.    
+ *    
+ * <b>Scaling and Overflow Behavior:</b>    
+ * \par    
+ * The function uses saturating arithmetic.    
+ * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.    
+ */
+
+void arm_shift_q15(
+  q15_t * pSrc,
+  int8_t shiftBits,
+  q15_t * pDst,
+  uint32_t blockSize)
+{
+  uint32_t blkCnt;                               /* loop counter */
+  uint8_t sign;                                  /* Sign of shiftBits */
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+/* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  q15_t in1, in2;                                /* Temporary variables */
+
+
+  /*loop Unrolling */
+  blkCnt = blockSize >> 2u;
+
+  /* Getting the sign of shiftBits */
+  sign = (shiftBits & 0x80);
+
+  /* If the shift value is positive then do right shift else left shift */
+  if(sign == 0u)
+  {
+    /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
+     ** a second loop below computes the remaining 1 to 3 samples. */
+    while(blkCnt > 0u)
+    {
+      /* Read 2 inputs */
+      in1 = *pSrc++;
+      in2 = *pSrc++;
+      /* C = A << shiftBits */
+      /* Shift the inputs and then store the results in the destination buffer. */
+#ifndef  ARM_MATH_BIG_ENDIAN
+
+      *__SIMD32(pDst)++ = __PKHBT(__SSAT((in1 << shiftBits), 16),
+                                  __SSAT((in2 << shiftBits), 16), 16);
+
+#else
+
+      *__SIMD32(pDst)++ = __PKHBT(__SSAT((in2 << shiftBits), 16),
+                                  __SSAT((in1 << shiftBits), 16), 16);
+
+#endif /* #ifndef  ARM_MATH_BIG_ENDIAN    */
+
+      in1 = *pSrc++;
+      in2 = *pSrc++;
+
+#ifndef  ARM_MATH_BIG_ENDIAN
+
+      *__SIMD32(pDst)++ = __PKHBT(__SSAT((in1 << shiftBits), 16),
+                                  __SSAT((in2 << shiftBits), 16), 16);
+
+#else
+
+      *__SIMD32(pDst)++ = __PKHBT(__SSAT((in2 << shiftBits), 16),
+                                  __SSAT((in1 << shiftBits), 16), 16);
+
+#endif /* #ifndef  ARM_MATH_BIG_ENDIAN    */
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+
+    /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
+     ** No loop unrolling is used. */
+    blkCnt = blockSize % 0x4u;
+
+    while(blkCnt > 0u)
+    {
+      /* C = A << shiftBits */
+      /* Shift and then store the results in the destination buffer. */
+      *pDst++ = __SSAT((*pSrc++ << shiftBits), 16);
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+  }
+  else
+  {
+    /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
+     ** a second loop below computes the remaining 1 to 3 samples. */
+    while(blkCnt > 0u)
+    {
+      /* Read 2 inputs */
+      in1 = *pSrc++;
+      in2 = *pSrc++;
+
+      /* C = A >> shiftBits */
+      /* Shift the inputs and then store the results in the destination buffer. */
+#ifndef  ARM_MATH_BIG_ENDIAN
+
+      *__SIMD32(pDst)++ = __PKHBT((in1 >> -shiftBits),
+                                  (in2 >> -shiftBits), 16);
+
+#else
+
+      *__SIMD32(pDst)++ = __PKHBT((in2 >> -shiftBits),
+                                  (in1 >> -shiftBits), 16);
+
+#endif /* #ifndef  ARM_MATH_BIG_ENDIAN    */
+
+      in1 = *pSrc++;
+      in2 = *pSrc++;
+
+#ifndef  ARM_MATH_BIG_ENDIAN
+
+      *__SIMD32(pDst)++ = __PKHBT((in1 >> -shiftBits),
+                                  (in2 >> -shiftBits), 16);
+
+#else
+
+      *__SIMD32(pDst)++ = __PKHBT((in2 >> -shiftBits),
+                                  (in1 >> -shiftBits), 16);
+
+#endif /* #ifndef  ARM_MATH_BIG_ENDIAN    */
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+
+    /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
+     ** No loop unrolling is used. */
+    blkCnt = blockSize % 0x4u;
+
+    while(blkCnt > 0u)
+    {
+      /* C = A >> shiftBits */
+      /* Shift the inputs and then store the results in the destination buffer. */
+      *pDst++ = (*pSrc++ >> -shiftBits);
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+  }
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* Getting the sign of shiftBits */
+  sign = (shiftBits & 0x80);
+
+  /* If the shift value is positive then do right shift else left shift */
+  if(sign == 0u)
+  {
+    /* Initialize blkCnt with number of samples */
+    blkCnt = blockSize;
+
+    while(blkCnt > 0u)
+    {
+      /* C = A << shiftBits */
+      /* Shift and then store the results in the destination buffer. */
+      *pDst++ = __SSAT(((q31_t) * pSrc++ << shiftBits), 16);
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+  }
+  else
+  {
+    /* Initialize blkCnt with number of samples */
+    blkCnt = blockSize;
+
+    while(blkCnt > 0u)
+    {
+      /* C = A >> shiftBits */
+      /* Shift the inputs and then store the results in the destination buffer. */
+      *pDst++ = (*pSrc++ >> -shiftBits);
+
+      /* Decrement the loop counter */
+      blkCnt--;
+    }
+  }
+
+#endif /* #ifndef ARM_MATH_CM0_FAMILY */
+
+}
+
+/**    
+ * @} end of shift group    
+ */