DSP_Lib/Source/BasicMathFunctions/arm_scale_q31.c - third_party/github/STMicroelectronics/cmsis_core - Git at Google

 /* ----------------------------------------------------------------------
 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
 *
 * $Date:        19. March 2015
 * $Revision: 	V.1.4.5
 *
 * Project: 	    CMSIS DSP Library
 * Title:		arm_scale_q31.c
 *
 * Description:	Multiplies a Q31 vector by a scalar.
 *
 * 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 scale
  * @{
  */

 /**
  * @brief Multiplies a Q31 vector by a scalar.
  * @param[in]       *pSrc points to the input vector
  * @param[in]       scaleFract fractional portion of the scale value
  * @param[in]       shift number of bits to shift the result by
  * @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 input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.31 format.
  * These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format.
  */

 void arm_scale_q31(
   q31_t * pSrc,
   q31_t scaleFract,
   int8_t shift,
   q31_t * pDst,
   uint32_t blockSize)
 {
   int8_t kShift = shift + 1;                     /* Shift to apply after scaling */
   int8_t sign = (kShift & 0x80);
   uint32_t blkCnt;                               /* loop counter */
   q31_t in, out;

 #ifndef ARM_MATH_CM0_FAMILY

 /* Run the below code for Cortex-M4 and Cortex-M3 */

   q31_t in1, in2, in3, in4;                      /* temporary input variables */
   q31_t out1, out2, out3, out4;                  /* temporary output variabels */


   /*loop Unrolling */
   blkCnt = blockSize >> 2u;

   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 four inputs from source */
       in1 = *pSrc;
       in2 = *(pSrc + 1);
       in3 = *(pSrc + 2);
       in4 = *(pSrc + 3);

       /* multiply input with scaler value */
       in1 = ((q63_t) in1 * scaleFract) >> 32;
       in2 = ((q63_t) in2 * scaleFract) >> 32;
       in3 = ((q63_t) in3 * scaleFract) >> 32;
       in4 = ((q63_t) in4 * scaleFract) >> 32;

       /* apply shifting */
       out1 = in1 << kShift;
       out2 = in2 << kShift;

       /* saturate the results. */
       if(in1 != (out1 >> kShift))
         out1 = 0x7FFFFFFF ^ (in1 >> 31);

       if(in2 != (out2 >> kShift))
         out2 = 0x7FFFFFFF ^ (in2 >> 31);

       out3 = in3 << kShift;
       out4 = in4 << kShift;

       *pDst = out1;
       *(pDst + 1) = out2;

       if(in3 != (out3 >> kShift))
         out3 = 0x7FFFFFFF ^ (in3 >> 31);

       if(in4 != (out4 >> kShift))
         out4 = 0x7FFFFFFF ^ (in4 >> 31);

       /* Store result destination */
       *(pDst + 2) = out3;
       *(pDst + 3) = out4;

       /* Update pointers to process next sampels */
       pSrc += 4u;
       pDst += 4u;

       /* 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 four inputs from source */
       in1 = *pSrc;
       in2 = *(pSrc + 1);
       in3 = *(pSrc + 2);
       in4 = *(pSrc + 3);

       /* multiply input with scaler value */
       in1 = ((q63_t) in1 * scaleFract) >> 32;
       in2 = ((q63_t) in2 * scaleFract) >> 32;
       in3 = ((q63_t) in3 * scaleFract) >> 32;
       in4 = ((q63_t) in4 * scaleFract) >> 32;

       /* apply shifting */
       out1 = in1 >> -kShift;
       out2 = in2 >> -kShift;

       out3 = in3 >> -kShift;
       out4 = in4 >> -kShift;

       /* Store result destination */
       *pDst = out1;
       *(pDst + 1) = out2;

       *(pDst + 2) = out3;
       *(pDst + 3) = out4;

       /* Update pointers to process next sampels */
       pSrc += 4u;
       pDst += 4u;

       /* 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;

 #else

   /* Run the below code for Cortex-M0 */

   /* Initialize blkCnt with number of samples */
   blkCnt = blockSize;

 #endif /* #ifndef ARM_MATH_CM0_FAMILY */

   if(sign == 0)
   {
 	  while(blkCnt > 0u)
 	  {
 		/* C = A * scale */
 		/* Scale the input and then store the result in the destination buffer. */
 		in = *pSrc++;
 		in = ((q63_t) in * scaleFract) >> 32;

 		out = in << kShift;

 		if(in != (out >> kShift))
 			out = 0x7FFFFFFF ^ (in >> 31);

 		*pDst++ = out;

 		/* Decrement the loop counter */
 		blkCnt--;
 	  }
   }
   else
   {
 	  while(blkCnt > 0u)
 	  {
 		/* C = A * scale */
 		/* Scale the input and then store the result in the destination buffer. */
 		in = *pSrc++;
 		in = ((q63_t) in * scaleFract) >> 32;

 		out = in >> -kShift;

 		*pDst++ = out;

 		/* Decrement the loop counter */
 		blkCnt--;
 	  }

   }
 }

 /**
  * @} end of scale group
  */
	/* ----------------------------------------------------------------------
	* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
	*
	* $Date: 19. March 2015
	* $Revision: V.1.4.5
	*
	* Project: CMSIS DSP Library
	* Title: arm_scale_q31.c
	*
	* Description: Multiplies a Q31 vector by a scalar.
	*
	* 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 scale
	* @{
	*/

	/**
	* @brief Multiplies a Q31 vector by a scalar.
	* @param[in] *pSrc points to the input vector
	* @param[in] scaleFract fractional portion of the scale value
	* @param[in] shift number of bits to shift the result by
	* @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 input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.31 format.
	* These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format.
	*/

	void arm_scale_q31(
	q31_t * pSrc,
	q31_t scaleFract,
	int8_t shift,
	q31_t * pDst,
	uint32_t blockSize)
	{
	int8_t kShift = shift + 1; /* Shift to apply after scaling */
	int8_t sign = (kShift & 0x80);
	uint32_t blkCnt; /* loop counter */
	q31_t in, out;

	#ifndef ARM_MATH_CM0_FAMILY

	/* Run the below code for Cortex-M4 and Cortex-M3 */

	q31_t in1, in2, in3, in4; /* temporary input variables */
	q31_t out1, out2, out3, out4; /* temporary output variabels */


	/loop Unrolling /
	blkCnt = blockSize >> 2u;

	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 four inputs from source */
	in1 = *pSrc;
	in2 = *(pSrc + 1);
	in3 = *(pSrc + 2);
	in4 = *(pSrc + 3);

	/* multiply input with scaler value */
	in1 = ((q63_t) in1 * scaleFract) >> 32;
	in2 = ((q63_t) in2 * scaleFract) >> 32;
	in3 = ((q63_t) in3 * scaleFract) >> 32;
	in4 = ((q63_t) in4 * scaleFract) >> 32;

	/* apply shifting */
	out1 = in1 << kShift;
	out2 = in2 << kShift;

	/* saturate the results. */
	if(in1 != (out1 >> kShift))
	out1 = 0x7FFFFFFF ^ (in1 >> 31);

	if(in2 != (out2 >> kShift))
	out2 = 0x7FFFFFFF ^ (in2 >> 31);

	out3 = in3 << kShift;
	out4 = in4 << kShift;

	*pDst = out1;
	*(pDst + 1) = out2;

	if(in3 != (out3 >> kShift))
	out3 = 0x7FFFFFFF ^ (in3 >> 31);

	if(in4 != (out4 >> kShift))
	out4 = 0x7FFFFFFF ^ (in4 >> 31);

	/* Store result destination */
	*(pDst + 2) = out3;
	*(pDst + 3) = out4;

	/* Update pointers to process next sampels */
	pSrc += 4u;
	pDst += 4u;

	/* 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 four inputs from source */
	in1 = *pSrc;
	in2 = *(pSrc + 1);
	in3 = *(pSrc + 2);
	in4 = *(pSrc + 3);

	/* multiply input with scaler value */
	in1 = ((q63_t) in1 * scaleFract) >> 32;
	in2 = ((q63_t) in2 * scaleFract) >> 32;
	in3 = ((q63_t) in3 * scaleFract) >> 32;
	in4 = ((q63_t) in4 * scaleFract) >> 32;

	/* apply shifting */
	out1 = in1 >> -kShift;
	out2 = in2 >> -kShift;

	out3 = in3 >> -kShift;
	out4 = in4 >> -kShift;

	/* Store result destination */
	*pDst = out1;
	*(pDst + 1) = out2;

	*(pDst + 2) = out3;
	*(pDst + 3) = out4;

	/* Update pointers to process next sampels */
	pSrc += 4u;
	pDst += 4u;

	/* 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;

	#else

	/* Run the below code for Cortex-M0 */

	/* Initialize blkCnt with number of samples */
	blkCnt = blockSize;

	#endif /* #ifndef ARM_MATH_CM0_FAMILY */

	if(sign == 0)
	{
	while(blkCnt > 0u)
	{
	/* C = A * scale */
	/* Scale the input and then store the result in the destination buffer. */
	in = *pSrc++;
	in = ((q63_t) in * scaleFract) >> 32;

	out = in << kShift;

	if(in != (out >> kShift))
	out = 0x7FFFFFFF ^ (in >> 31);

	*pDst++ = out;

	/* Decrement the loop counter */
	blkCnt--;
	}
	}
	else
	{
	while(blkCnt > 0u)
	{
	/* C = A * scale */
	/* Scale the input and then store the result in the destination buffer. */
	in = *pSrc++;
	in = ((q63_t) in * scaleFract) >> 32;

	out = in >> -kShift;

	*pDst++ = out;

	/* Decrement the loop counter */
	blkCnt--;
	}

	}
	}

	/**
	* @} end of scale group
	*/