dsp_blk_eswap16.h64

来自「dm642函数库」· H64 代码 · 共 95 行

;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  DSPLIB  DSP Signal Processing Library                                   *;
;*                                                                          *;
;*      Release:        Revision 1.04b                                      *;
;*      CVS Revision:   1.3     Sun Sep 29 03:32:17 2002 (UTC)              *;
;*      Snapshot date:  23-Oct-2003                                         *;
;*                                                                          *;
;*  This library contains proprietary intellectual property of Texas        *;
;*  Instruments, Inc.  The library and its source code are protected by     *;
;*  various copyrights, and portions may also be protected by patents or    *;
;*  other legal protections.                                                *;
;*                                                                          *;
;*  This software is licensed for use with Texas Instruments TMS320         *;
;*  family DSPs.  This license was provided to you prior to installing      *;
;*  the software.  You may review this license by consulting the file       *;
;*  TI_license.PDF which accompanies the files in this library.             *;
;* ------------------------------------------------------------------------ *;
;*          Copyright (C) 2003 Texas Instruments, Incorporated.             *;
;*                          All Rights Reserved.                            *;
;* ======================================================================== *;
;* ======================================================================== *;
;*  Assembler compatibility shim for assembling 4.30 and later code on      *;
;*  tools prior to 4.30.                                                    *;
;* ======================================================================== *;
;* ======================================================================== *;
;*  End of assembler compatibility shim.                                    *;
;* ======================================================================== *;
* ========================================================================= *
*   NAME                                                                    *
*       DSP_blk_eswap16 -- Endian-swap a block of 16-bit values             *
*                                                                           *
*   REVISION DATE                                                           *
*       10-Aug-2001                                                         *
*                                                                           *
*   USAGE                                                                   *
*       This routine has the following C prototype:                         *
*                                                                           *
*           void DSP_blk_eswap16                                            *
*           (                                                               *
*               void *restrict src,     /* Source data                 */   *
*               void *restrict dst,     /* Destination array           */   *
*               int  n_hwords           /* Number of halfwords to swap */   *
*           );                                                              *
*                                                                           *
*       This function performs an endian-swap on the data in the "src"      *
*       array, writing the results to "dst".  If NULL is passed in for      *
*       the destination, then the endian-swap is performed in-place.        *
*       The "n_hwords" argument gives the total length of the array in      *
*       half-words.                                                         *
*                                                                           *
*   DESCRIPTION                                                             *
*       The data in the "src" array is endian swapped, meaning that the     *
*       byte-order of the bytes within each word of the src[] array is      *
*       reversed.  This is meant to facilitate moving big-endian data       *
*       to a little-endian system or vice-versa.                            *
*                                                                           *
*       When the "dst" pointer is non-NULL, the endian-swap occurs          *
*       out-of-place, similar to a block move.  When the "dst" pointer      *
*       is NULL, the endian-swap occurs in-place, allowing the swap to      *
*       occur without using any additional storage.                         *
*                                                                           *
*   ASSUMPTIONS                                                             *
*       Input and output arrays do not overlap, except in the very          *
*       specific case that "dst == NULL" so that the operation occurs       *
*       in-place.                                                           *
*                                                                           *
*       The input array and output array are expected to be double-word     *
*       aligned, and a multiple of 8 half-words must be processed.          *
*                                                                           *
*   NOTES                                                                   *
*       This function locks out interrupts for its entire duration.         *
*       It is interrupt tolerant, but not interruptible.                    *
*                                                                           *
*   CODESIZE                                                                *
*       116 bytes                                                           *
*                                                                           *
*   CYCLES                                                                  *
*       cycles = 18 + n_hwords / 8.                                         *
*                                                                           *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *

        .global _DSP_blk_eswap16

* ========================================================================= *
*   End of file:  dsp_blk_eswap16.h64                                       *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *