img_yc_demux_be16.h64

dm642函数库

;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  IMGLIB  DSP Image/Video Processing Library                              *;
;*                                                                          *;
;*      Release:        Revision 1.04b                                      *;
;*      CVS Revision:   1.6     Sun Sep 29 03:32:31 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.                                    *;
;* ======================================================================== *;
* ========================================================================= *
*   TEXAS INSTRUMENTS, INC.                                                 *
*                                                                           *
*   NAME                                                                    *
*       IMG_yc_demux_be16 -- De-interleave a 4:2:2 BIG ENDIAN video stream  *
*                        into three separate LITTLE ENDIAN 16-bit planes    *
*                                                                           *
*   REVISION DATE                                                           *
*       09-Oct-2001                                                         *
*                                                                           *
*   USAGE                                                                   *
*       This function is C callable, and is called as follows:              *
*                                                                           *
*       void IMG_yc_demux_be16                                              *
*       (                                                                   *
*           int n,                       // Number of luma pixels    //     *
*           const unsigned char * yc,    // Interleaved luma/chroma  //     *
*           short *restrict y,           // Luma plane (16-bit)      //     *
*           short *restrict cr,          // Cr chroma plane (16-bit) //     *
*           short *restrict cb           // Cb chroma plane (16-bit) //     *
*       );                                                                  *
*                                                                           *
*       The input array 'yc' is expected to be an interleaved 4:2:2         *
*       video stream.  The input is expected in BIG ENDIAN byte order       *
*       within each 4-byte word.  This is consistent with reading the       *
*       video stream from a word-oriented BIG ENDIAN device while the       *
*       C6000 device is in a LITTLE ENDIAN configuration.                   *
*                                                                           *
*       In other words, the expected pixel order is:                        *
*                                                                           *
*                   Word 0           Word 1          Word 2                 *
*              +---------------+---------------+---------------+--          *
*        Byte# | 0   1   2   3 | 4   5   6   7 | 8   9  10  11 |...         *
*              |cb0 y1  cr0 y0 |cb2 y3  cr2 y2 |cb4 y5  cr4 y4 |...         *
*              +---------------+---------------+---------------+--          *
*                                                                           *
*       The output arrays 'y', 'cr', and 'cb' are expected to not           *
*       overlap.  The de-interleaved pixels are written as half-words       *
*       in LITTLE ENDIAN order.                                             *
*                                                                           *
*   DESCRIPTION                                                             *
*       This function reads the byte-oriented pixel data, zero-extends      *
*       it, and then writes it to the appropriate result array.  Both       *
*       the luma and chroma values are expected to be unsigned.             *
*                                                                           *
*       The data is expected to be in an order consistent with reading      *
*       byte oriented data from a word-oriented peripheral that is          *
*       operating in BIG ENDIAN mode, while the CPU is in LITTLE ENDIAN     *
*       mode.  This results in a pixel ordering which is not                *
*       immediately obvious.  This function correctly reorders the          *
*       pixel values so that further processing may proceed in LITTLE       *
*       ENDIAN mode.                                                        *
*                                                                           *
*   ASSUMPTIONS                                                             *
*       Input and output arrays are double-word aligned.                    *
*       The input must be a multiple of 16 luma pixels long.                *
*                                                                           *
*   TECHNIQUES                                                              *
*       The loop has been unrolled a total of 16 times to allow for         *
*       processing 8 pixels in each datapath.                               *
*                                                                           *
*       Double-word loads and stores maximize memory bandwidth              *
*       utilization.                                                        *
*                                                                           *
*       This code uses _gmpy4() to ease the L/S/D unit bottleneck on        *
*       ANDs.  The _gmpy4(value, 0x00010001) is equivalent to               *
*       value & 0x00FF00FF, as long as the size field of GFPGFR is          *
*       equal to 7.  (The polynomial does not matter.)                      *
*                                                                           *
*   NOTES                                                                   *
*       This kernel is fully interruptible.                                 *
*                                                                           *
*   CYCLES                                                                  *
*       cycles = 3 * (num_luma / 8) + 18.                                   *
*       For num_luma = 1024, cycles = 402.                                  *
*                                                                           *
*       This number includes 6 cycles of function call overhead.  The       *
*       exact overhead will vary depending on compiler options used.        *
*                                                                           *
*   CODESIZE                                                                *
*       316 bytes                                                           *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *

        .global _IMG_yc_demux_be16

* ========================================================================= *
*   End of file:  img_yc_demux_be16.h64                                     *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *