Commit 1d586e8e authored by Arthur Tritthart's avatar Arthur Tritthart
Browse files

modified lookup s17 function

parent eeae8dbd

lib_com/options.h

+1 −0
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ 
#define FIX_2383_INIT_Q_A_ITF                           /* FhG: Initialize Q_A_itf, to avoid reading of uninitialized memory in case ITF is not triggered */

#define FIX_2382_COPY_AQ_IN_MCT                         /* FhG: basop issue 2382: 2nd instance of prevent copying uninitialized values from Aq_fx[][] to Aq_fx_32[][] in TCX */

#define FIX_2391_INIT_HQ_GENERIC_OFFSET                 /* FhG/Eri: basop issue 2391: make sure hq_generic_offset is initialized inside hq_hr_dec_fx() */

#define FIX_2402_SIMPLIFY_ARI_CODEC                     /* FhG: basop issue 2402: simplify processing in arithmetic decoding, symbol table lookup, all BE */



/* #################### End BE switches ################################## */

lib_dec/ari_dec_fx.c

+41 −1
Original line number Diff line number Diff line
@@ -13,6 +13,16 @@ 
 * Ari decode 14 bits routines

  -------------------------------------------------------------*/



#ifdef FIX_2402_SIMPLIFY_ARI_CODEC

static Word32 L_msui_32_16(Word32 cum, Word32 range, Word16 cum_freq)

{

    /* WMOPS counting is done using L_sub, similar to other MSU operations */

    /* Note: range*cum_freq do never exceed signed 32-bit, when multiplied */

    /* Note: No overflow or saturation feature required.                   */

    return L_sub(cum, range * cum_freq );

}

#endif



Word32 ari_decode_overflow_fx( Tastat *s )

{

    return ( L_sub( L_sub( s->high, 1 ), s->low ) <= 0 );
@@ -77,9 +87,11 @@ static Word16 ari_lookup_s17_fx( 
    UWord16 const *cum_freq /* Q0 */

)

{

    Word32 tmp;

    const UWord16 *p;

#ifndef FIX_2402_SIMPLIFY_ARI_CODEC

    Word32 tmp;

    Word16 range_l, range_h;

#endif



    p = cum_freq;
@@ -88,6 +100,7 @@ static Word16 ari_lookup_s17_fx( 
    /*    tmp_p = p+8; if (tmp_p[0]*range>cum) p = tmp_p;                                                             */



    /* max value in p[x] is 16384 => 14 bits */

#ifndef FIX_2402_SIMPLIFY_ARI_CODEC

    range_l = extract_l( L_and( range, 0x7FFF ) );

    range_h = extract_l( L_shr( range, 15 ) );
@@ -122,6 +135,33 @@ static Word16 ari_lookup_s17_fx( 
            p = p + 1;

        }

    }

#else

    if (L_msui_32_16(cum, range, p[8]) < 0)

    { 

        p = p + 8; 

        move16();

    }

    if (L_msui_32_16(cum, range, p[4]) < 0)

    { 

        p = p + 4; 

        move16();

    }

    if (L_msui_32_16(cum, range, p[2]) < 0)

    { 

        p = p + 2; 

        move16();

    }

    if (L_msui_32_16(cum, range, p[1]) < 0)

    { 

        p = p + 1; 

        move16();

        IF( EQ_32( (Word32) ( &cum_freq[15] - p ), 0 ) && (L_msui_32_16(cum, range, p[1] )  < 0) )

        {

            p = p + 1; 

            move16();

        }

    }

#endif



    /* return extract_l(L_shr(L_sub((Word32)p,(Word32)cum_freq),1)); */

    L_sub( 0, 0 );