omxsp_iirone_biquaddirect_s16.c

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

/**
 * 
 * File Name:  omxSP_IIROne_BiQuadDirect_S16.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 single sample biuad IIR filtering
 *
 */

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


/**
 * Function:  omxSP_IIROne_BiQuadDirect_S16   (2.2.3.3.2)
 *
 * Description:
 * Single-sample biquad IIR filtering for 16-bit data type. This function 
 * applies the direct form II biquad IIR cascade defined by the coefficient 
 * vector pTaps to a single sample of input data.  The internal accumulator 
 * width must be at least 32 bits, and the result is saturated if the 
 * operation produces a value outside the range of a signed 16-bit integer, 
 * i.e., the output will saturate to 0x8000 (-32768) for a negative overflow 
 * or 0x7fff (32767) for a positive overflow.  The result is undefined if any 
 * of the partially accumulated values exceeds the range of a signed 32-bit 
 * integer. 
 *
 * Input Arguments:
 *   
 *   val   - the single input sample to which the filter is 
 *            applied. 
 *   pTaps - pointer to the 6P-element vector that contains the combined 
 *            numerator and denominator filter coefficients from the biquad 
 *            cascade. Coefficient scaling and coefficient vector organization 
 *            should follow the conventions described above. The value of the 
 *            coefficient scalefactor exponent must be non-negative: (sfp>=0). 
 *   numBiquad - the number of biquads contained in the IIR filter cascade: 
 *            (P) 
 *   pDelayLine - pointer to the 2p-element filter memory buffer (state). The 
 *            user is responsible for allocation, initialization, and 
 *            deallocation. The filter memory elements are initialized to zero 
 *            in most applications. 
 *
 * Output Arguments:
 *   
 *   pResult - pointer to the filtered output sample 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments; returned if one or more of the 
 *              following is true: 
 *    -    one or more of the following pointers is NULL: pResult, 
 *              pValResult, pTaps, or pDelayLine. 
 *    -    numBiquad < 1 
 *    -    pTaps[3+n*6] < 0, for 0 <= n < numBiquad (negative scaling) 
 *
 */

OMXResult omxSP_IIROne_BiQuadDirect_S16(
     OMX_S16 val,
     OMX_S16 * pResult,
     const OMX_S16 * pTaps,
     OMX_INT numBiquad,
     OMX_S32 * pDelayLine
 )
{

    OMX_S16 InOut;
    OMX_S32 Temp1,Temp2;
    OMX_S32 Mac;

    /* Argument Check */
    armRetArgErrIf( pResult    == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pDelayLine == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( pTaps      == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf( numBiquad  <= 0   , OMX_Sts_BadArgErr);
    
    /* Processing */
    InOut = val;

    while(numBiquad != 0)
    {
        /* Argument Check */   
        armRetArgErrIf( pTaps[3] <  0     , OMX_Sts_BadArgErr);
    
        Temp1 = pDelayLine[0];
        Temp2 = pDelayLine[1];

        /* Accumulate Am's */

        Mac = armSatMac_S16S32_S32(0  , Temp1 , pTaps[4]);
        Mac = armSatMac_S16S32_S32(Mac, Temp2 , pTaps[5]);

        Mac = armSatSub_S32( armSatRoundLeftShift_S32(InOut, pTaps[3]) , Mac);
        Mac = armSatRoundLeftShift_S32(Mac,-pTaps[3]);
        
        /* Shift The DelayLine */

        pDelayLine[0] = Mac;
        pDelayLine[1] = Temp1;

        /* Accumulate Bk's */
                
        Mac = armSatMac_S16S32_S32(0  , Mac,   pTaps[0] );
        Mac = armSatMac_S16S32_S32(Mac, Temp1, pTaps[1] );
        Mac = armSatMac_S16S32_S32(Mac, Temp2, pTaps[2] );

        /* Output */
        InOut = armSatRoundRightShift_S32_S16(Mac, pTaps[3]);

        numBiquad--;

        pTaps += 6;
        pDelayLine += 2;
    
    }/*end while(numBiquad != 0)*/
                   
    *pResult = InOut;

    return OMX_Sts_NoErr;

}

 /* End of File */