img_pix_sat.h64

TMS320C64x Image／Video Processing Library (V1.04)

;* ======================================================================== *;
;*  TEXAS INSTRUMENTS, INC.                                                 *;
;*                                                                          *;
;*  IMGLIB  DSP Image/Video Processing Library                              *;
;*                                                                          *;
;*      Release:        Revision 1.04b                                      *;
;*      CVS Revision:   1.5     Sun Sep 29 03:32:27 2002 (UTC)              *;
;*      Snapshot date:  23-Oct-2003                                         *;
;*                                                                          *;
;*  This library contains proprietary intellectual property of Texas        *;
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;*  other legal protections.                                                *;
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;*  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.                            *;
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;* ======================================================================== *;
;*  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_pix_sat -- Pixel saturate and pack.                             *
*                                                                           *
*   REVISION DATE                                                           *
*       23-May-2000                                                         *
*                                                                           *
*   USAGE                                                                   *
*       This routine is C callable, and has the following C prototype:      *
*                                                                           *
*           void IMG_pix_sat                                                *
*           (                                                               *
*               int n,                            /* Number of pixels */    *
*               const short   *restrict in_data,  /* Incoming data    */    *
*               unsigned char *restrict out_data  /* Outgoing data    */    *
*           );                                                              *
*                                                                           *
*   DESCRIPTION                                                             *
*       The function IMG_pix_sat() takes signed 16-bit input pixels and     *
*       saturates them to unsigned 8-bit results.  Pixel values above       *
*       255 are clamped to 255, and values below 0 are clamped to 0.        *
*                                                                           *
*   TECHNIQUES                                                              *
*       The inner loop has been unrolled to fill a 6 cycle loop.  This      *
*       allows the code to be interruptible.                                *
*                                                                           *
*       The prolog and epilog have been collapsed into the kernel.  Also,   *
*       most of the setup and all of the exit code has been overlapped      *
*       with the kernel.  The result is that the function runs with a       *
*       very minimum amount of overhead.                                    *
*                                                                           *
*   ASSUMPTIONS                                                             *
*       The input size must be a multiple of 32 pixels.  The code behaves   *
*       correctly if a pixel count of zero is passed in.                    *
*                                                                           *
*   NOTES                                                                   *
*       This code is fully interruptible.                                   *
*                                                                           *
*   MEMORY NOTE                                                             *
*       The input and output data must be double-word aligned.              *
*                                                                           *
*       This code accesses 128 bits every cycle.  No bank conflicts occur.  *
*                                                                           *
*   CYCLES                                                                  *
*       cycles = (pixels / 16) * 3 + 13                                     *
*       (This includes 6 cycles of function call overhead.)                 *
*       For pixels = 640, cycles = 133.                                     *
*                                                                           *
*   CODESIZE                                                                *
*       116 bytes.                                                          *
*                                                                           *
* ------------------------------------------------------------------------- *
*             Copyright (c) 2003 Texas Instruments, Incorporated.           *
*                            All Rights Reserved.                           *
* ========================================================================= *

        .global _IMG_pix_sat

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