Fix for 3GPP issue 1478: Encoder crash (assert) in ISM1, GSC encoder

    move16();

    Word16 ratio_fx;

    Word16 attack_pos_fx, i;

    Word32 L_tmp, L_tmp1;

    Word16 tmp, n1, n2, exp, frac1, frac2;

    Word32 L_tmp;

    Word16 tmp, tmp_e;

    Word32 etmp1_fx;

    Word16 etmp_e;

    Word16 att_len;

    test();

        IF( GT_32( etmp_fx, *Last_frame_ener_fx ) && attack_pos_fx > 0 )

        {

            /* Find the average energy before the attack */

            L_tmp = sum32_fx( finc_fx, attack_pos_fx );                  /*Q1 */

            L_tmp1 = L_shr( L_mult( attack_pos_fx, attack_pos_fx ), 1 ); /*Q0 */

            tmp = round_fx( Isqrt( L_tmp1 ) );                           /*Q15 */

            L_tmp = L_shr( L_tmp, 2 );                                   /*Q1 ; ATT_SEG_LEN=4 */

            etmp_fx = Mult_32_16( L_tmp, tmp );                          /*Q1 */

            etmp_fx = sum32_fx( finc_fx, attack_pos_fx );

            etmp_e = sub( 31, add( shl( Q_new, 1 ), 1 ) );

            etmp_fx = L_add( etmp_fx, L_shr( 21474836 /*0.01 in Q31*/, etmp_e ) ); /* etmp = etmp + 0.01;   (exp = etmp_e) */

            etmp_fx = L_deposit_h( BASOP_Util_Divide3232_Scale( etmp_fx, L_mult0( attack_pos_fx, ATT_SEG_LEN ), &tmp_e ) );

            tmp_e = add( tmp_e, sub( etmp_e, 31 ) );

            etmp_e = tmp_e;

            move16();

            etmp_fx = L_shr( etmp_fx, add( 1 - 4, shl( Q_new, 1 ) ) ); /* makes etmp i nQ4 as *Last_frame_ener_fx */

            /* Find the correction factor and apply it before the attack */

                                                                       /*   ratio = (float)sqrt(*Last_frame_ener/etmp);*/

                                                                       /*         = isqrt(etmp/(*Last_frame_ener))			*/

            etmp_fx = L_max( etmp_fx, 1 );

            *Last_frame_ener_fx = L_max( *Last_frame_ener_fx, 1 );

            move32();

            n1 = norm_l( etmp_fx );

            n2 = norm_l( *Last_frame_ener_fx );

            n1 = sub( n1, 1 );

            exp = sub( n1, n2 );

            frac1 = round_fx( L_shl( etmp_fx, n1 ) );

            frac2 = round_fx_sat( L_shl_sat( *Last_frame_ener_fx, n2 ) );

            L_tmp = L_mult0( 128, div_s( frac1, frac2 ) ); /* s = gain_out / gain_in */

            L_tmp = L_shr( L_tmp, exp );                   /* add exponent */

            L_tmp = Isqrt( L_tmp );

            ratio_fx = round_fx( L_shl( L_tmp, 9 ) );

            tmp = BASOP_Util_Divide3232_Scale( *Last_frame_ener_fx, etmp_fx, &tmp_e ); /* numerator Q = 2 * Q_new + 1;  denominator Q = 31 - tmp_e */

            tmp_e = add( tmp_e, sub( sub( 31, etmp_e ), add( shl( Q_new, 1 ), 1 ) ) ); /* tmp_e = tmp_e + (31 - tmp_e) - (2 * Q_new + 1) */

            tmp = Sqrt16( tmp, &tmp_e );

            ratio_fx = shr( tmp, sub( 2, tmp_e ) ); /* Q13 */

            /* Pre-echo atttenuation should never increase the energy */

            ratio_fx = s_min( ratio_fx, 8192 /* 1 in Q13 */ ); /* Q13 */