CMSIS DSP Software Library: arm_abs_q7.c Source File

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# arm_abs_q7.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        15. July 2011
    00005 * $Revision:    V1.0.10
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_abs_q7.c
    00009 *
    00010 * Description:  Q7 vector absolute value.
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
    00013 *
    00014 * Version 1.0.10 2011/7/15
    00015 *    Big Endian support added and Merged M0 and M3/M4 Source code.
    00016 *
    00017 * Version 1.0.3 2010/11/29
    00018 *    Re-organized the CMSIS folders and updated documentation.
    00019 *
    00020 * Version 1.0.2 2010/11/11
    00021 *    Documentation updated.
    00022 *
    00023 * Version 1.0.1 2010/10/05
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 1.0.0 2010/09/20
    00027 *    Production release and review comments incorporated.
    00028 *
    00029 * Version 0.0.7  2010/06/10
    00030 *    Misra-C changes done
    00031 * -------------------------------------------------------------------- */
    00032
    00033 #include "arm_math.h"
    00034
    00057 void arm_abs_q7(
    00058   q7_t * pSrc,
    00059   q7_t * pDst,
    00060   uint32_t blockSize)
    00061 {
    00062   uint32_t blkCnt;                               /* loop counter */
    00063
    00064 #ifndef ARM_MATH_CM0
    00065
    00066   /* Run the below code for Cortex-M4 and Cortex-M3 */
    00067   q7_t in1;                                      /* Input value1 */
    00068   q7_t in2;                                      /* Input value2 */
    00069   q7_t in3;                                      /* Input value3 */
    00070   q7_t in4;                                      /* Input value4 */
    00071
    00072
    00073   /*loop Unrolling */
    00074   blkCnt = blockSize >> 2u;
    00075
    00076   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00077    ** a second loop below computes the remaining 1 to 3 samples. */
    00078   while(blkCnt > 0u)
    00079   {
    00080     /* C = |A| */
    00081     /* Read 4 inputs */
    00082     in1 = *pSrc++;
    00083     in2 = *pSrc++;
    00084     in3 = *pSrc++;
    00085     in4 = *pSrc++;
    00086
    00087     /* Store the Absolute result in the destination buffer by packing the 4 values in single cycle */
    00088     *__SIMD32(pDst)++ =
    00089       __PACKq7(((in1 > 0) ? in1 : __SSAT(-in1, 8)),
    00090                ((in2 > 0) ? in2 : __SSAT(-in2, 8)),
    00091                ((in3 > 0) ? in3 : __SSAT(-in3, 8)),
    00092                ((in4 > 0) ? in4 : __SSAT(-in4, 8)));
    00093
    00094     /* Decrement the loop counter */
    00095     blkCnt--;
    00096   }
    00097
    00098   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00099    ** No loop unrolling is used. */
    00100   blkCnt = blockSize % 0x4u;
    00101
    00102   while(blkCnt > 0u)
    00103   {
    00104     /* C = |A| */
    00105     /* Read the input */
    00106     in1 = *pSrc++;
    00107
    00108     /* Store the Absolute result in the destination buffer */
    00109     *pDst++ = (in1 > 0) ? in1 : __SSAT(-in1, 8);
    00110
    00111     /* Decrement the loop counter */
    00112     blkCnt--;
    00113   }
    00114
    00115 #else
    00116
    00117   /* Run the below code for Cortex-M0 */
    00118
    00119   q7_t in;                                       /* Temporary input varible */
    00120
    00121   /* Initialize blkCnt with number of samples */
    00122   blkCnt = blockSize;
    00123
    00124   while(blkCnt > 0u)
    00125   {
    00126     /* C = |A| */
    00127     /* Read the input */
    00128     in = *pSrc++;
    00129
    00130     /* Store the Absolute result in the destination buffer */
    00131     *pDst++ = (in > 0) ? in : __SSAT(-in, 8);
    00132
    00133     /* Decrement the loop counter */
    00134     blkCnt--;
    00135   }
    00136
    00137 #endif /*   #ifndef ARM_MATH_CM0   */
    00138
    00139 }
    00140

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