img_sad_8x8.h64

TMS320C64x Image／Video Processing Library (V1.04)

;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  IMGLIB  DSP Image/Video Processing Library                              *;
;*                                                                          *;
;*      Release:        Revision 1.04b                                      *;
;*      CVS Revision:   1.4     Sun Sep 29 03:32:29 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                                                                    *
*       IMG_sad_8x8 -- Sum of Absolute Differences on single 16x16 block    *
*                                                                           *
*   USAGE                                                                   *
*       unsigned IMG_sad_8x8                                                *
*       (                                                                   *
*           const unsigned char *restrict srcImg,  /* 8x8 source block   */ *
*           const unsigned char *restrict refImg,  /* Reference image    */ *
*           int pitch                              /* Width of ref image */ *
*       );                                                                  *
*                                                                           *
*       The code accepts a pointer to the 8x8 source block (srcImg),        *
*       and a pointer to the upper-left corner of a target position in      *
*       a reference image (refImg).  The width of the reference image       *
*       is given by the pitch argument.                                     *
*                                                                           *
*       The function returns the sum of the absolute differences            *
*       between the source block and the 8x8 region pointed to in the       *
*       reference image.                                                    *
*                                                                           *
*   DESCRIPTION                                                             *
*       The algorithm takes the difference between the pixel values in      *
*       the source image block and the corresponding pixels in the          *
*       reference image.  It then takes the absolute values of these        *
*       differences, and accumulates them over the entire 8x8 region.       *
*       It returns the final accumulation.                                  *
*                                                                           *
*   C CODE                                                                  *
*       The following is a C code description of the algorithm that lacks   *
*       restrictions.  The assembly code may have additional restrictions   *
*       as noted below.                                                     *
*                                                                           *
*           unsigned IMG_sad_8x8                                            *
*           (                                                               *
*               const unsigned char *restrict srcImg,                       *
*               const unsigned char *restrict refImg,                       *
*               int pitch                                                   *
*           )                                                               *
*           {                                                               *
*               int i, j;                                                   *
*               unsigned sad = 0;                                           *
*                                                                           *
*               for (i = 0; i < 8; i++)                                     *
*                   for (j = 0; j < 8; j++)                                 *
*                       sad += abs(srcImg[j+i*8] - refImg[j+i*pitch]);      *
*                                                                           *
*               return sad;                                                 *
*           }                                                               *
*                                                                           *
*   ASSUMPTIONS                                                             *
*       Some versions of this kernel may assume that srcImg is double-      *
*       word aligned.                                                       *
*                                                                           *
*   MEMORY NOTE                                                             *
*       No bank conflicts occur.                                            *
*       Endian Neutral.                                                     *
*                                                                           *
*   NOTES                                                                   *
*       This kernel blocks interrupts for 25 cycles.                        *
*                                                                           *
*   CYCLES                                                                  *
*       31 cycles                                                           *
*                                                                           *
*   CODESIZE                                                                *
*       164 bytes                                                           *
*                                                                           *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *

        .global _IMG_sad_8x8

* ========================================================================= *
*   End of file:  img_sad_8x8.h64                                           *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *