omxsp_dotprod_s16_sfs.c

The OpenMAX DL (Development Layer) APIs contain a comprehensive set of audio, video, signal processi

/**
 * 
 * File Name:  omxSP_DotProd_S16_Sfs.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 *
 * Description:
 * This file contains module for dot product of two vectors
 *
 */

#include "omxtypes.h"
#include "armOMX.h"
#include "omxSP.h"
#include "armCOMM.h"

/**
 * Function:  omxSP_DotProd_S16_Sfs   (2.2.2.1.2)
 *
 * Description:
 * Calculates the dot product of the two input signals with output scaling 
 * and saturation, i.e., the result is multiplied by two to the power of the 
 * negative (-)scalefactor (scaled) prior to return.  The result is saturated 
 * with rounding if the scaling operation produces a value outside the range 
 * of a signed 32-bit integer. Rounding behavior is defined in section 1.6.7 
 * Integer Scaling and Rounding Conventions. The internal accumulator width 
 * must be at least 32 bits. The result is undefined if any of the partially 
 * accumulated values exceeds the range of a signed 32-bit integer. 
 *
 * Input Arguments:
 *   
 *   pSrc1 - pointer to the first input vector; must be aligned on an 8-byte 
 *            boundary. 
 *   pSrc2 - pointer to the second input vector; must be aligned on an 8-byte 
 *            boundary. 
 *   len - length of the vectors in pSrc1 and pSrc2 
 *   scaleFactor - integer scalefactor 
 *
 * Output Arguments:
 *
 * Return Value:
 *    
 *    The dot product result  Note: This function returns the actual result 
 *              rather than the standard OMXError. 
 *
 */

OMX_S32 omxSP_DotProd_S16_Sfs(
                            const OMX_S16 *pSrc1,
                            const OMX_S16 *pSrc2,
                            OMX_INT       len,
                            OMX_INT       scaleFactor
                            )
{
    OMX_S32 DotProd;
    OMX_S16 Var1,Var2;
    
    
    /* Return if value 'len' is not valid */
        
    if(len <= 0)
    {
       return (OMX_S32)0;
    }
    
    /* Compute the DotProduct */
    
    DotProd = 0;
    
    do
    {
        Var1 = *pSrc1++;
        Var2 = *pSrc2++;
        
        DotProd += (OMX_S32)(Var1*Var2);

        len--;
        
    }while(len != 0);

    /* Scale the result of the operation */
    
    DotProd = armSatRoundLeftShift_S32(DotProd,-scaleFactor);
    
    return DotProd;
    

}

 /* End of File */