diff --git a/lib_com/ivas_arith_fx.c b/lib_com/ivas_arith_fx.c
index aa261f69daab8bf32323b2299d212927b82d3afb..c9eba0ec32c43a49ef973c9d1f6c527e93b911d5 100644
--- a/lib_com/ivas_arith_fx.c
+++ b/lib_com/ivas_arith_fx.c
@@ -102,6 +102,7 @@ static UWord16 ivas_ari_get_symbol(
  *
  *-------------------------------------------------------------*/
 
+#ifndef FIX_2402_SIGNED_VERSION
 UWord16 ivas_ari_decode_14bits_bit_ext_1_lfe(
     Decoder_State *st,
     Tastat *s,
@@ -180,6 +181,87 @@ UWord16 ivas_ari_decode_14bits_bit_ext_1_lfe(
 
     return symbol;
 }
+#else /* FIX_2402_SIGNED_VERSION */
+Word16 ivas_ari_decode_14bits_bit_ext_1_lfe(
+    Decoder_State *st,
+    Tastat *s,
+    const UWord16 *cum_freq,
+    Word16 *extra_bits_read )
+{
+    Word16 symbol;
+    Word32 low, high, range, value;
+    Word32 cum;
+
+    /* read s->low,high,value sequentially */
+    low = s->low;
+    high = s->high;
+    value = s->value;
+
+    move32();
+    move32();
+    move32();
+
+    range = L_add( L_sub( high, low ), 1 );
+    cum = L_sub( L_lshl( ( L_add( L_sub( value, low ), 1 ) ), stat_bitsnew ), 1 );
+
+    symbol = ivas_ari_get_symbol( cum_freq, range, cum );
+
+    high = L_sub( L_add( low, mul_sbc_14bits( range, cum_freq[symbol] ) ), 1 );
+    low = L_add( low, mul_sbc_14bits( range, cum_freq[symbol + 1] ) );
+
+    FOR( ;; )
+    {
+        IF( GE_32( high, ari_q2new ) )
+        {
+            IF( GE_32( low, ari_q2new ) )
+            {
+                value = L_sub( value, ari_q2new );
+                low = L_sub( low, ari_q2new );
+                high = L_sub( high, ari_q2new );
+            }
+            ELSE
+            {
+                test();
+                IF( GE_32( low, ari_q1new ) && LT_32( high, ari_q3new ) )
+                {
+                    value = L_sub( value, ari_q1new );
+                    low = L_sub( low, ari_q1new );
+                    high = L_sub( high, ari_q1new );
+                }
+                ELSE
+                {
+                    BREAK;
+                }
+            }
+        }
+
+        low = L_add( low, low );
+        high = L_add( high, UL_addNsD( high, 1 ) );
+
+        IF( GE_16( st->next_bit_pos, st->bits_frame ) )
+        {
+            value = L_lshl( value, 1 );
+            *extra_bits_read = add( *extra_bits_read, 1 );
+            move16();
+        }
+        ELSE
+        {
+            value = L_or( L_lshl( value, 1 ), get_next_indice_1_fx( st ) );
+        }
+    }
+
+    s->low = low;
+    s->high = high;
+    s->value = value;
+
+    move32();
+    move32();
+    move32();
+
+    return symbol;
+}
+
+#endif /* FIX_2402_SIGNED_VERSION */
 
 /*---------------------------------------------------------------
  * Function ivas_ari_done_decoding_14bits_ext_1_lfe()
diff --git a/lib_com/ivas_prot_fx.h b/lib_com/ivas_prot_fx.h
index 910e872b250668f076aec21662bc638695d523ce..ee15a9897d0fdce95a65519bc0b5298e8ad5b347 100644
--- a/lib_com/ivas_prot_fx.h
+++ b/lib_com/ivas_prot_fx.h
@@ -5332,12 +5332,21 @@ void ivas_ari_start_decoding_14bits_ext_1_lfe(
     Word16 *extra_bits_read 
 );
 
+#ifndef FIX_2402_SIGNED_VERSION
 UWord16 ivas_ari_decode_14bits_bit_ext_1_lfe(
     Decoder_State *st,
     Tastat *s,
     const UWord16 *cum_freq,
     Word16 *extra_bits_read 
 );
+#else
+Word16 ivas_ari_decode_14bits_bit_ext_1_lfe(
+    Decoder_State *st,
+    Tastat *s,
+    const UWord16 *cum_freq,
+    Word16 *extra_bits_read 
+);
+#endif
 
 void ivas_ari_done_decoding_14bits_ext_1_lfe(
     Decoder_State *st,
diff --git a/lib_com/options.h b/lib_com/options.h
index 9ce33d497451049e7dbee57598e3a596b0c93473..924f6d6b37b30a0b2258fc4b8ad7eed2ef756d47 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -94,6 +94,9 @@
 #define FIX_FLOAT_1539_G192_FORMAT_SWITCH               /* VA/Nokia: reintroduce format switching for g192 bitstreams */
 #define SIMPLIFY_CORE_ENC                               /* VA: basop issue 2430: Simplify ivas_core_enc_fx() */
 #define FIX_2402_SIMPLIFY_ARI_CODEC                     /* FhG: basop issue 2402: simplified arithmetic in TCX arithmetic coder */
+#define FIX_2402_INLINE_FCT_ARI_CODEC                   /* FhG: basop issue 2402: simplify processing in arithmetic decoding, inline mul_sbc_14bits, all BE */
+#define FIX_2402_REPL_EVS_ARI_CODEC_DEC               /* FhG: basop issue 2402: replace EVS arith decoder with IVAS arith decoder, except functions in igf_scf_dec_fx.c */
+#define FIX_2402_SIGNED_VERSION                         /* FhG: basop issue 2402: use signed operator instead of unsigned, better match for hardware */
 #define FIX_2402_REPL_EVS_ARI_CODEC_ENC                 /* FhG: basop issue 2402: replace EVS arith encoder with IVAS arith encoder */
 #define FIX_BASOP_2551_HARM_SCALAR_QUAN                 /* FhG: issue 2551: Harmonize function pair tcx_scalar_quantization_fx*/
 #define HARMONIZE_2564_GetEnergyCldfb                   /* FhG: harmonize GetEnergyCldfb derivates for evs/ivas  */
diff --git a/lib_com/prot_fx.h b/lib_com/prot_fx.h
index 7d541d076f4dd6b8b77823483077bf91514954b8..ebcf72afe2174cde480162f463c73475cd864899 100644
--- a/lib_com/prot_fx.h
+++ b/lib_com/prot_fx.h
@@ -7508,6 +7508,9 @@ void IGFSCFDecoderDecode(
 Word32 ari_decode_overflow_fx(
     Tastat *s );
 
+Word32 ari_decode_overflow_ivas_fx(
+    Tastat *s );
+
 void ari_start_decoding_14bits_fx(
     Decoder_State *st,
     Tastat *s );
diff --git a/lib_dec/ACcontextMapping_dec_fx.c b/lib_dec/ACcontextMapping_dec_fx.c
index a483972ff03667aecefb49b507754601b6314db9..5b11b86028c3ed9df0c6951c92b2a90ab99c6b4f 100644
--- a/lib_dec/ACcontextMapping_dec_fx.c
+++ b/lib_dec/ACcontextMapping_dec_fx.c
@@ -13,6 +13,9 @@
 #include "ivas_prot_fx.h"
 #include "ivas_rom_com.h"
 
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+#include "ivas_prot_fx.h"
+#endif
 
 /*-------------------------------------------------------------------*
  * ACcontextMapping_decode2_no_mem_s17_LC()
@@ -133,7 +136,12 @@ Word16 ACcontextMapping_decode2_no_mem_s17_LC(
     }
 
     /* Start Decoding */
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+    Word16 extra_bits_read = 0;
+    ivas_ari_start_decoding_14bits_ext_1_lfe( st, &as, &extra_bits_read );
+#else
     ari_start_decoding_14bits_fx( st, &as );
+#endif
 
     overflow_bit_pos = st->next_bit_pos;
     move16();
@@ -182,8 +190,11 @@ Word16 ACcontextMapping_decode2_no_mem_s17_LC(
             assert( tmp >= 0 && tmp < 4096 );
             pki = ari_lookup_s17_LC[tmp];
             move16();
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+            r = ivas_ari_decode_14bits_bit_ext_1_lfe( st, &as, ari_pk_s17_LC_ext[pki], &extra_bits_read );
+#else
             r = ari_decode_14bits_s17_ext_fx( st, &as, ari_pk_s17_LC_ext[pki] );
-
+#endif
             IF( LT_16( r, VAL_ESC ) )
             {
                 BREAK;
@@ -280,8 +291,13 @@ Word16 ACcontextMapping_decode2_no_mem_s17_LC(
         }
     }
 
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+    ivas_ari_done_decoding_14bits_ext_1_lfe( st, extra_bits_read );
+#endif
     /* Total number of decoded AC bits */
+#ifndef FIX_2402_REPL_EVS_ARI_CODEC_DEC
     get_next_indice_tmp_fx( st, -( cbitsnew - 2 ) );
+#endif
 
     /*detect overflow*/
     IF( NE_16( k, lastnz ) )
diff --git a/lib_dec/ari_dec_fx.c b/lib_dec/ari_dec_fx.c
index 99d33cc5992403f56c750c58acec1cabc395018a..68b8b79d423044f3e6aafe82a5b40b68ddbd20ad 100644
--- a/lib_dec/ari_dec_fx.c
+++ b/lib_dec/ari_dec_fx.c
@@ -25,13 +25,16 @@ static Word32 L_msui_32_16( Word32 cum, Word32 range, Word16 cum_freq )
 
 Word32 ari_decode_overflow_fx( Tastat *s )
 {
-#ifdef FIX_2402_SIMPLIFY_ARI_CODEC
-    return ( L_sub( s->high, s->low ) <= 0 );
-#else
     return ( L_sub( L_sub( s->high, 1 ), s->low ) <= 0 );
-#endif
 }
 
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+Word32 ari_decode_overflow_ivas_fx( Tastat *s )
+{
+    return ( L_sub( s->high, s->low ) <= 0 );
+}
+#endif
+
 /**
  * \brief     Start ArCo decoding
  *
@@ -64,19 +67,29 @@ Word16 ari_start_decoding_14bits_prm_fx(
     const Word16 *p;
 
     val = L_deposit_l( 0 );
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+    s->low = val;
+    move32();
+#endif
 
     p = ptr + bp; /* Q0 */
 
     FOR( i = 0; i < cbitsnew; i++ )
     {
         val = L_shl( val, 1 );
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+        if ( *( p + i ) != 0 )
+#else
         IF( *( p + i ) )
+#endif
         {
             val = L_add( val, 1 );
         }
     }
+#ifndef FIX_2402_REPL_EVS_ARI_CODEC_DEC
     s->low = L_deposit_l( 0 );
     move32();
+#endif
     s->high = L_add( ari_q4new, 1 );
     move32();
     s->value = val;
@@ -85,6 +98,7 @@ Word16 ari_start_decoding_14bits_prm_fx(
     return add( bp, i );
 }
 
+#ifndef FIX_2402_REPL_EVS_ARI_CODEC_DEC
 static Word16 ari_lookup_s17_fx(
     Word32 cum,
     Word32 range,
@@ -172,6 +186,7 @@ static Word16 ari_lookup_s17_fx(
     L_shr( 0, 0 ); /* pointer subtraction */
     return extract_l( p - cum_freq );
 }
+#endif /* FIX_2402_REPL_EVS_ARI_CODEC_DEC */
 
 static Word16 ari_lookup_s27_fx(
     Word32 cum,
@@ -416,10 +431,12 @@ static Word16 ari_decode_14bits_ext_fx(
 /**
  * \brief Only for 17 symbols with new extended Tables
  */
+#ifndef FIX_2402_REPL_EVS_ARI_CODEC_DEC
 Word16 ari_decode_14bits_s17_ext_fx( Decoder_State *st, Tastat *s, UWord16 const *cum_freq )
 {
     return ari_decode_14bits_ext_fx( st, s, cum_freq, ari_lookup_s17_fx );
 }
+#endif /* FIX_2402_REPL_EVS_ARI_CODEC_DEC */
 
 /**
  * \brief Only for 27 symbols with new extended Tables
@@ -656,7 +673,11 @@ Word16 ari_decode_14bits_pow_fx( Word16 *ptr, Word16 bp, Word16 bits, Word16 *re
  *-------------------------------------------------------------------------*/
 Word16 ari_decode_14bits_sign_fx( Word16 *ptr, Word16 bp, Word16 bits, Word16 *res, Tastat *s )
 {
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+    return ari_decode_14bits_sign_ivas( ptr, bp, bits, res, s );
+#else
     return ari_decode_14bits_notbl_fx( ptr, bp, bits, res, s, 0, ari_lookup_sign_fx );
+#endif
 }
 
 /*---------------------------------------------------------------
diff --git a/lib_dec/arith_coder_dec_fx.c b/lib_dec/arith_coder_dec_fx.c
index 3ac4963c0e31df182d139bf30e31e674e24d990c..b7d2636ac1a55907dbafe8697043534a18835385 100644
--- a/lib_dec/arith_coder_dec_fx.c
+++ b/lib_dec/arith_coder_dec_fx.c
@@ -31,7 +31,11 @@ static Word16 tcx_arith_decode_fx(
     Word64 W_tmp;
     move32();
 
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+    bp = ari_start_decoding_14bits_prm_ivas_fx( prm, 0, &as );
+#else
     bp = ari_start_decoding_14bits_prm_fx( prm, 0, &as );
+#endif /* FIX_2402_REPL_EVS_ARI_CODEC_DEC */
 
     tmp = sub( envelope_e, 1 + 15 );
     W_tmp = 0;
@@ -48,7 +52,11 @@ static Word16 tcx_arith_decode_fx(
             exp_k = round_fx( expfp( envelope[k], tmp ) );
         }
         /* decode line magnitude */
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+        bp = ari_decode_14bits_pow_ivas( prm, bp, target_bits, &q, &as, exp_k );
+#else
         bp = ari_decode_14bits_pow_fx( prm, bp, target_bits, &q, &as, exp_k );
+#endif /* FIX_2402_REPL_EVS_ARI_CODEC_DEC */
 
         IF( q == 0 )
         {
@@ -57,7 +65,12 @@ static Word16 tcx_arith_decode_fx(
         }
         IF( q != 0 ) /* line is non-zero, decode sign */
         {
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+            bp = ari_decode_14bits_sign_ivas( prm, bp, target_bits, &s, &as );
+            s = sub( s, 1 ); /* ivas returns 1 or 2, evs expects 0 or 1 */
+#else
             bp = ari_decode_14bits_sign_fx( prm, bp, target_bits, &s, &as );
+#endif /* FIX_2402_REPL_EVS_ARI_CODEC_DEC */
 
             W_tmp = W_mac_16_16( W_tmp, q, k );
 
@@ -68,7 +81,11 @@ static Word16 tcx_arith_decode_fx(
             move32();
         }
 
+#ifdef FIX_2402_REPL_EVS_ARI_CODEC_DEC
+        IF( ari_decode_overflow_ivas_fx( &as ) )
+#else
         IF( ari_decode_overflow_fx( &as ) )
+#endif /* FIX_2402_REPL_EVS_ARI_CODEC_DEC */
         {
             if ( LT_16( bp, target_bits ) ) /* safety check in case of bit errors */
             {