/* ----------------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 16/10/14 6:01p $Revision:  V.1.4.5
*
* Project:      CMSIS DSP Library
* Title:        arm_q31_to_q7.c
*
* Description:  Converts the elements of the Q31 vector to Q7 vector.
*
* 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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* ---------------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupSupport
 */

/**
 * @addtogroup q31_to_x
 * @{
 */

/**
 * @brief Converts the elements of the Q31 vector to Q7 vector.
 * @param[in]       *pSrc points to the Q31 input vector
 * @param[out]      *pDst points to the Q7 output vector
 * @param[in]       blockSize length of the input vector
 * @return none.
 *
 * \par Description:
 *
 * The equation used for the conversion process is:
 *
 * <pre>
 *  pDst[n] = (q7_t) pSrc[n] >> 24;   0 <= n < blockSize.
 * </pre>
 *
 */


void arm_q31_to_q7(
    q31_t * pSrc,
    q7_t * pDst,
    uint32_t blockSize)
{
    q31_t *pIn = pSrc;                             /* Src pointer */
    uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    q31_t in1, in2, in3, in4;
    q7_t out1, out2, out3, out4;

    /*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 = (q7_t) A >> 24 */
        /* convert from q31 to q7 and then store the results in the destination buffer */
        in1 = *pIn++;
        in2 = *pIn++;
        in3 = *pIn++;
        in4 = *pIn++;

        out1 = (q7_t)(in1 >> 24);
        out2 = (q7_t)(in2 >> 24);
        out3 = (q7_t)(in3 >> 24);
        out4 = (q7_t)(in4 >> 24);

        *__SIMD32(pDst)++ = __PACKq7(out1, out2, out3, out4);

        /* 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 */

    /* Loop over blockSize number of values */
    blkCnt = blockSize;

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    while(blkCnt > 0u)
    {
        /* C = (q7_t) A >> 24 */
        /* convert from q31 to q7 and then store the results in the destination buffer */
        *pDst++ = (q7_t)(*pIn++ >> 24);

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

}

/**
 * @} end of q31_to_x group
 */
