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# arm_negate_q7.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        29. November 2010
    00005 * $Revision:    V1.0.3
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_negate_q7.c
    00009 *
    00010 * Description:  Negates Q7 vectors.
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3
    00013 *
    00014 * Version 1.0.3 2010/11/29
    00015 *    Re-organized the CMSIS folders and updated documentation.
    00016 *
    00017 * Version 1.0.2 2010/11/11
    00018 *    Documentation updated.
    00019 *
    00020 * Version 1.0.1 2010/10/05
    00021 *    Production release and review comments incorporated.
    00022 *
    00023 * Version 1.0.0 2010/09/20
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 0.0.7  2010/06/10
    00027 *    Misra-C changes done
    00028 * -------------------------------------------------------------------- */
    00029
    00030 #include "arm_math.h"
    00031
    00054 void arm_negate_q7(
    00055   q7_t * pSrc,
    00056   q7_t * pDst,
    00057   uint32_t blockSize)
    00058 {
    00059   uint32_t blkCnt;                               /* loop counter */
    00060   q7_t in1;                                      /* Input value1 */
    00061   q7_t in2;                                      /* Input value2 */
    00062   q7_t in3;                                      /* Input value3 */
    00063   q7_t in4;                                      /* Input value4 */
    00064
    00065
    00066   /*loop Unrolling */
    00067   blkCnt = blockSize >> 2u;
    00068
    00069   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00070    ** a second loop below computes the remaining 1 to 3 samples. */
    00071   while(blkCnt > 0u)
    00072   {
    00073     /* C = ~A */
    00074     /* Read four inputs */
    00075     in1 = *pSrc++;
    00076     in2 = *pSrc++;
    00077     in3 = *pSrc++;
    00078     in4 = *pSrc++;
    00079
    00080     /* Store the Negated results in the destination buffer in a single cycle by packing the results */
    00081     *__SIMD32(pDst)++ =
    00082       __PACKq7(__SSAT(-in1, 8), __SSAT(-in2, 8), __SSAT(-in3, 8),
    00083                __SSAT(-in4, 8));
    00084
    00085     /* Decrement the loop counter */
    00086     blkCnt--;
    00087   }
    00088
    00089   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00090    ** No loop unrolling is used. */
    00091   blkCnt = blockSize % 0x4u;
    00092
    00093   while(blkCnt > 0u)
    00094   {
    00095     /* C = ~A */
    00096     /* Negate and then store the results in the destination buffer. */
    00097     *pDst++ = __SSAT(-*pSrc++, 8);
    00098
    00099     /* Decrement the loop counter */
    00100     blkCnt--;
    00101   }
    00102 }
    00103

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