/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 16/10/14 6:00p $Revision:  V.1.4.5
*
* Project:      CMSIS DSP Library
* Title:        arm_abs_q31.c
*
* Description:  Q31 vector absolute value.
*
* 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;
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* POSSIBILITY OF SUCH DAMAGE.
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupMath
 */

/**
 * @addtogroup BasicAbs
 * @{
 */


/**
 * @brief Q31 vector absolute value.
 * @param[in]       *pSrc points to the input buffer
 * @param[out]      *pDst points to the output buffer
 * @param[in]       blockSize number of samples in each vector
 * @return none.
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function uses saturating arithmetic.
 * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
 */

void arm_abs_q31(
    q31_t * pSrc,
    q31_t * pDst,
    uint32_t blockSize)
{
    uint32_t blkCnt;                               /* loop counter */
    q31_t in;                                      /* Input value */

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    q31_t in1, in2, in3, in4;

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

    /* 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)
    {
        /* C = |A| */
        /* Calculate absolute of input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
        in1 = *pSrc++;
        in2 = *pSrc++;
        in3 = *pSrc++;
        in4 = *pSrc++;

        *pDst++ = (in1 > 0) ? in1 : (q31_t)__QSUB(0, in1);
        *pDst++ = (in2 > 0) ? in2 : (q31_t)__QSUB(0, in2);
        *pDst++ = (in3 > 0) ? in3 : (q31_t)__QSUB(0, in3);
        *pDst++ = (in4 > 0) ? in4 : (q31_t)__QSUB(0, in4);

        /* 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   */

    while(blkCnt > 0u)
    {
        /* C = |A| */
        /* Calculate absolute value of the input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
        in = *pSrc++;
        *pDst++ = (in > 0) ? in : ((in == INT32_MIN) ? INT32_MAX : -in);

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

}

/**
 * @} end of BasicAbs group
 */
