- Main Page
- Modules
- Data Structures
- Files
- Examples

- File List
- Globals

# arm_abs_q7.c

Go to the documentation of this file.

    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_abs_q7.c
    00009 *
    00010 * Description:  Q7 vector absolute value.
    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_abs_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 4 inputs */
    00075     in1 = *pSrc++;
    00076     in2 = *pSrc++;
    00077     in3 = *pSrc++;
    00078     in4 = *pSrc++;
    00079
    00080     /* Store the Absolute result in the destination buffer by packing the 4 values in single cycle */
    00081     *__SIMD32(pDst)++ =
    00082       __PACKq7(((in1 > 0) ? in1 : __SSAT(-in1, 8)),
    00083                ((in2 > 0) ? in2 : __SSAT(-in2, 8)),
    00084                ((in3 > 0) ? in3 : __SSAT(-in3, 8)),
    00085                ((in4 > 0) ? in4 : __SSAT(-in4, 8)));
    00086
    00087     /* Decrement the loop counter */
    00088     blkCnt--;
    00089   }
    00090
    00091   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00092    ** No loop unrolling is used. */
    00093   blkCnt = blockSize % 0x4u;
    00094
    00095   while(blkCnt > 0u)
    00096   {
    00097     /* C = |A| */
    00098     /* Read the input */
    00099     in1 = *pSrc++;
    00100
    00101     /* Store the Absolute result in the destination buffer */
    00102     *pDst++ = (in1 > 0) ? in1 : __SSAT(-in1, 8);
    00103
    00104     /* Decrement the loop counter */
    00105     blkCnt--;
    00106   }
    00107 }
    00108

All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Defines