diff --git a/lib_com/basop_util.c b/lib_com/basop_util.c
index ec6c89896dcb67d234a75087071c291a8c4775ec..fe2b7e871a0ebe2aca06094cb879427b4593ef71 100644
--- a/lib_com/basop_util.c
+++ b/lib_com/basop_util.c
@@ -2072,12 +2072,18 @@ Word16 idiv1616_1( Word16 x, Word16 y )
     }
 }
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
 Word32 norm_llQ31(               /* o : normalized result              Q31 */
                    Word32 L_c,   /* i : upper bits of accu             Q-1 */
                    Word32 L_sum, /* i : lower bits of accu, unsigned   Q31 */
                    Word16 *exp   /* o : exponent of result in [-32,31]  Q0 */
 )
 {
+#ifdef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+    move32(); /* compensate missing instrumentation */
+    move32(); /* compensate missing instrumentation */
+    return w_norm_llQ31( ( (Word64) L_c << 32 ) | (UWord32) L_sum, exp );
+#else
     Word16 i;
     Word32 L_tmp;
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
@@ -2088,8 +2094,8 @@ Word32 norm_llQ31(               /* o : normalized result              Q31 */
 #endif /* BASOP_NOGLOB */
 
     /* Move MSBit of L_sum into L_c */
-    Carry = 0;
 #ifdef ISSUE_1836_replace_overflow_libcom
+    Carry = 0;
     L_tmp = L_add_c( L_sum, L_sum, &Carry ); /* L_tmp = L_sum << 1         */
     L_c = L_add_c( L_c, L_c, &Carry );
 #else
@@ -2121,7 +2127,9 @@ Word32 norm_llQ31(               /* o : normalized result              Q31 */
     *exp = i;
     move16();
     return L_sum;
+#endif /* #ifdef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW */
 }
+#endif /* #ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW */
 
 
 Word32 Dot_product16HQ(                     /* o : normalized result              Q31 */
diff --git a/lib_com/basop_util.h b/lib_com/basop_util.h
index 9e5882f2224fd7b8aee34603ca03d89c5a076996..e6db321da23b9caa126676f83ea2ad6f8c3b8ae3 100644
--- a/lib_com/basop_util.h
+++ b/lib_com/basop_util.h
@@ -647,7 +647,10 @@ Word32 norm_llQ31(               /* o : normalized result              Q31 */
  * \brief Compute normalized Q31 Values out of overflowed Q31 value
  *        using 64-bit operators
  *------------------------------------------------------------------*/
-static inline Word32 w_norm_llQ31( Word64 L64_var1, Word16 *S_var2 ) /*Q31 - L_tmp_exp*/
+static inline Word32 w_norm_llQ31(                  /* o : normalized result               Q31 - *S_var2 */
+                                   Word64 L64_var1, /* i : 64-bit accu                     Q63           */
+                                   Word16 *S_var2   /* o : exponent of result in [-32,31]  Q0            */
+)
 {
     Word32 L_result;
     Word16 sh = W_norm( L64_var1 );
diff --git a/lib_com/igf_base_fx.c b/lib_com/igf_base_fx.c
index 44cf27c5f3da77010f5d13489439a0dc2bc507c7..e9aea5274e0cd2ba97755416455eb861b5b61ca0 100644
--- a/lib_com/igf_base_fx.c
+++ b/lib_com/igf_base_fx.c
@@ -1115,28 +1115,42 @@ void IGFCommonFuncsCalcSfbEnergyPowerSpec( const Word16 startSfb,        /**< in
 )
 {
     Word16 /*Q0*/ sfb;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word16 /*Q0*/ line;
     Word32 L_c;
+#endif
 
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
     move16();
     move16();
 #endif
+#endif
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     FOR( sfb = startSfb; sfb < stopSfb; sfb++ )
     {
         sfbEnergy[sfb] = L_deposit_l( 0 );
         move32();
     }
+#endif
     IF( NULL == pPowerSpectrum )
     {
+#ifdef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+        FOR( sfb = startSfb; sfb < stopSfb; sfb++ )
+        {
+            sfbEnergy[sfb] = L_deposit_l( 0 );
+            move32();
+        }
+#endif
         return;
     }
 
     FOR( sfb = startSfb; sfb < stopSfb; sfb++ )
     {
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         L_c = L_deposit_l( 0 );
         FOR( line = swb_offset[sfb]; line < swb_offset[sfb + 1]; line++ )
         {
@@ -1150,6 +1164,12 @@ void IGFCommonFuncsCalcSfbEnergyPowerSpec( const Word16 startSfb,        /**< in
         }
         sfbEnergy[sfb] = norm_llQ31( L_c, sfbEnergy[sfb], &( sfbEnergy_exp[sfb] ) );
         move32();
+#else
+        sfbEnergy[sfb] = sum_array_norm( pPowerSpectrum + swb_offset[sfb],
+                                         swb_offset[sfb + 1] - swb_offset[sfb],
+                                         &( sfbEnergy_exp[sfb] ) );
+        move32();
+#endif
         sfbEnergy_exp[sfb] = add( sfbEnergy_exp[sfb], *pPowerSpectrum_exp );
         move16();
     }
diff --git a/lib_com/options.h b/lib_com/options.h
index 397618990f28e710fe2097a1ac25358056f9899a..3e11805fcc15d132eae7fadd29420369ba9e6ad5 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -73,6 +73,7 @@
 
 /* Note: each compile switch (FIX_1101_...) is independent from the other ones */
 
+#define FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW                /* FhG: bit-exact, replace carry and overflow operations by 64-bit operations, MR 2166 */
 #define ISSUE_1836_replace_overflow_libcom                   /* FhG: BE - replace overflow operators by non-overflow-alternatives in lib_com */
 #define ISSUE_1867_replace_overflow_libenc                   /* FhG: BE - replace overflow operators by non-overflow-alternatives all over the lib_enc module */
 #define FIX_1942_ASSERTION_LOWSHELF                          /* FhG: Modified the target_gains_db_fx calculation in compute_t60_coeffs_fx() */
diff --git a/lib_dec/arith_coder_dec_fx.c b/lib_dec/arith_coder_dec_fx.c
index 60a59c4da469f113f7195179ed0521d2c343bc2d..77ae166b450b57fd108d9f0a948e902fb0772a3f 100644
--- a/lib_dec/arith_coder_dec_fx.c
+++ b/lib_dec/arith_coder_dec_fx.c
@@ -27,11 +27,16 @@ static Word16 tcx_arith_decode_fx(
     Tastat as;
     Word16 exp_k;
     Word16 tmp;
-    Word32 L_tmp, Q;
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+    Word32 L_tmp, Q;
     Flag Overflow = 0;
     move32();
     Flag Carry = 0;
+#else
+    Word32 Q;
+    Word64 W_tmp;
+#endif
     move32();
 #endif
 
@@ -39,7 +44,11 @@ static Word16 tcx_arith_decode_fx(
     bp = ari_start_decoding_14bits_prm_fx( prm, 0, &as );
 
     tmp = sub( envelope_e, 1 + 15 );
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     L_tmp = L_deposit_l( 0 );
+#else
+    W_tmp = 0;
+#endif
     FOR( k = 0; k < L_frame; k++ )
     {
         IF( envelope[k] == 0 ) /* safety check in case of bit errors */
@@ -63,7 +72,11 @@ static Word16 tcx_arith_decode_fx(
         {
             bp = ari_decode_14bits_sign_fx( prm, bp, target_bits, &s, &as );
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
             L_tmp = L_macNs_co( L_tmp, q, k, &Carry, &Overflow );
+#else
+            W_tmp = W_mac_16_16( W_tmp, q, k );
+#endif
 
             Q = L_mult( q, negate( shl( 1, sub( 30, SPEC_EXP_DEC ) ) ) );
             IF( EQ_16( s, 0 ) )
@@ -88,7 +101,11 @@ static Word16 tcx_arith_decode_fx(
     set32_fx( q_spectrum + k, 0, sub( L_frame, k ) );
 
     /* noise filling seed */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     *nf_seed = extract_l( L_tmp );
+#else
+    *nf_seed = extract_l( W_extract_l( W_tmp ) );
+#endif
     move16();
 
     return bp;
diff --git a/lib_dec/er_dec_tcx_fx.c b/lib_dec/er_dec_tcx_fx.c
index 16884caaa902d537f329163bf0b5518824a1d9b6..091b5ee5d50ffe52b44d87150452e7a04b675441 100644
--- a/lib_dec/er_dec_tcx_fx.c
+++ b/lib_dec/er_dec_tcx_fx.c
@@ -15,23 +15,36 @@
 ******************************************************/
 static void calcGainc_fx( Word16 *exc, Word16 Q_exc, Word32 old_fpitch /*Q16*/, Word16 L_subfr /*Q0*/, Word32 lp_gainp /*Q16*/, Word32 *lp_gainc /*Q16*/ )
 {
-    Word32 L_c;
     Word16 tmp16, tmp16_2, tmp16_3, tmp_e, tmp2_e, tmp_loop, i;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+    Word32 L_c;
     Word32 L_acc, L_tmp;
+#else
+    Word64 W_acc;
+    Word32 L_tmp;
+#endif
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
+#endif
     move32();
     move32();
 #endif
 
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     L_acc = L_deposit_l( 0 );
     L_c = L_deposit_l( 0 );
+#else
+    W_acc = 0;
+#endif
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Overflow = 0;
     move16();
     Carry = 0;
     move16();
+#endif
 
     tmp16 = round_fx( old_fpitch ); /*Q0*/
     tmp_loop = shl( L_subfr, 1 );
@@ -44,14 +57,22 @@ static void calcGainc_fx( Word16 *exc, Word16 Q_exc, Word32 old_fpitch /*Q16*/,
         /*st->lp_gainc += ( exc[i-2*L_subfr] - st->Mode2_lp_gainp * exc[i-2*L_subfr-(int)(st->old_fpitch+0.5f)] ) *
                           ( exc[i-2*L_subfr] - st->Mode2_lp_gainp * exc[i-2*L_subfr-(int)(st->old_fpitch+0.5f)] );*/
         tmp16_3 = sub_sat( exc[( i - ( L_subfr * 2 ) )] /*Q1*/, mult_r( tmp16_2 /*Q15*/, exc[( ( i - ( L_subfr * 2 ) ) - tmp16 )] /*Q1*/ ) /*Q1*/ );
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         L_acc = L_macNs_co( L_acc, tmp16_3, tmp16_3, &Carry, &Overflow ); /*Q3*/
         Overflow = 0;
         move16();
         L_c = L_macNs_co( L_c, 0, 0, &Carry, &Overflow ); /*Accumulate Carrys Q-1*/
         Carry = 0;
         move16();
+#else
+        W_acc = W_mac_16_16( W_acc, tmp16_3, tmp16_3 ); /*Q3*/
+#endif
     }
-    L_tmp = norm_llQ31( L_c, L_acc, &tmp_e );                 /*Q3,norm,tmp_e*/
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+    L_tmp = norm_llQ31( L_c, L_acc, &tmp_e ); /*Q3,norm,tmp_e*/
+#else
+    L_tmp = w_norm_llQ31( W_acc, &tmp_e );              /*Q3,norm,tmp_e*/
+#endif
     tmp_e = add( tmp_e, 31 - ( add( shl( Q_exc, 1 ), 1 ) ) ); /*L_tmp is Q31, now*/
     tmp16 = BASOP_Util_Divide3216_Scale( L_tmp /*Q31,norm,tmp_e*/, shl( L_subfr, 1 ) /*Q15,15*/, &tmp2_e ) /*Q15,tmp2_e+tmp_e-15*/;
     tmp_e = sub( add( tmp2_e, tmp_e ), 15 );
@@ -67,15 +88,23 @@ static void calcGainc_fx( Word16 *exc, Word16 Q_exc, Word32 old_fpitch /*Q16*/,
 static void calcGainc2_fx( Word16 *exc, Word16 Q_exc, Word16 L_subfr /*Q0*/, Word32 *lp_gainc /*Q16*/ )
 {
     Word16 i, cnt, tmp16, tmp_e, tmp2_e;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word32 L_c, L_acc, L_tmp;
+#else
+    Word64 W_acc;
+    Word32 L_tmp;
+#endif
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
+#endif
 #endif
     move16();
     move16();
 
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Carry = 0;
     move16();
     Overflow = 0;
@@ -83,21 +112,32 @@ static void calcGainc2_fx( Word16 *exc, Word16 Q_exc, Word16 L_subfr /*Q0*/, Wor
 
     L_c = L_deposit_l( 0 );
     L_acc = L_deposit_l( 0 );
+#else
+    W_acc = 0;
+#endif
 
     cnt = shl( L_subfr, 1 );
 
     FOR( i = 0; i < cnt; i++ )
     {
         /* *gainc += ( exc[i-2*L_subfr] ) * ( exc[i-2*L_subfr]); */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         L_acc = L_macNs_co( L_acc, exc[( i - ( L_subfr * 2 ) )] /*Q1*/, exc[( i - ( L_subfr * 2 ) )] /*Q1*/, &Carry, &Overflow ); /*Q3*/
         Overflow = 0;
         move16();
         L_c = L_macNs_co( L_c, 0, 0, &Carry, &Overflow ); /* Accumulate Carrys Q-1*/
         Carry = 0;
         move16();
+#else
+        W_acc = W_mac_16_16( W_acc, exc[( i - ( L_subfr * 2 ) )] /*Q1*/, exc[( i - ( L_subfr * 2 ) )] /*Q1*/ ); /*Q3*/
+#endif
     }
 
-    L_tmp = norm_llQ31( L_c, L_acc, &tmp_e );                       /*Q3,norm,tmp_e*/
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+    L_tmp = norm_llQ31( L_c, L_acc, &tmp_e ); /*Q3,norm,tmp_e*/
+#else
+    L_tmp = w_norm_llQ31( W_acc, &tmp_e );                                                                      /*Q3,norm,tmp_e*/
+#endif
     tmp_e = add( tmp_e, sub( 31, ( add( shl( Q_exc, 1 ), 1 ) ) ) ); /*L_tmp is Q31, now*/
     tmp16 = BASOP_Util_Divide3216_Scale( L_tmp /*Q31,norm,tmp_e*/, shl( L_subfr, 1 ) /*Q15,15*/, &tmp2_e ) /*Q15,tmp2_e+tmp_e-15*/;
     tmp_e = sub( add( tmp2_e, tmp_e ), 15 );
diff --git a/lib_dec/igf_dec_fx.c b/lib_dec/igf_dec_fx.c
index 1851c04a661c642a33c8a36e839c5b96990aa3f9..206627d924110c06cda37ecd4a6277cde81385d3 100644
--- a/lib_dec/igf_dec_fx.c
+++ b/lib_dec/igf_dec_fx.c
@@ -1482,11 +1482,15 @@ static void IGF_appl( IGF_DEC_PRIVATE_DATA_HANDLE hPrivateData,          /**< in
     Word16 dS[IGF_MAX_SFB];
     Word16 dS_e[IGF_MAX_SFB];
     Word32 energyTmp[24];
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word32 L_c;
+#endif
     Word16 Hr;
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
+#endif
     move16();
     move16();
 #endif
@@ -1565,6 +1569,7 @@ static void IGF_appl( IGF_DEC_PRIVATE_DATA_HANDLE hPrivateData,          /**< in
                                   &dE_e,
                                   negate( tmp ) );
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     L_c = 0;
     move32();
     FOR( tb = 0; tb < 24; tb++ )
@@ -1577,6 +1582,9 @@ static void IGF_appl( IGF_DEC_PRIVATE_DATA_HANDLE hPrivateData,          /**< in
         L_c = L_macNs_co( L_c, 0, 0, &Carry, &Overflow );
     }
     L_tmp = norm_llQ31( L_c, L_tmp, &shift ); // Q31
+#else
+    L_tmp = sum_array_norm( energyTmp, 24, &shift );
+#endif
     /* float: dE = (float)sqrt(dE / 24.f); basop: */
     shift = add( sub( shift, 4 ), dE_e ); /* x/24 = (x >> 4) * 1/1.5 */
     dE = Sqrt16norm( extract_h( L_tmp ), &shift );
@@ -2168,15 +2176,19 @@ static void IGF_appl_ivas( IGF_DEC_PRIVATE_DATA_HANDLE hPrivateData,     /**< in
     Word16 dS[IGF_MAX_SFB];
     Word16 dS_e[IGF_MAX_SFB];
     Word32 energyTmp[24];
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word32 L_c;
+#endif
     Word16 spec_e_arr[N_MAX];
     Word16 vspec_e_arr[N_MAX_TCX - IGF_START_MN];
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     move16();
     Flag Carry = 0;
     move16();
 #endif
+#endif
 
 
     /* initialize variables */
@@ -2254,6 +2266,7 @@ static void IGF_appl_ivas( IGF_DEC_PRIVATE_DATA_HANDLE hPrivateData,     /**< in
                                        &dE_e,
                                        negate( tmp ) );
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     L_c = 0;
     move32();
     FOR( tb = 0; tb < 24; tb++ )
@@ -2265,6 +2278,9 @@ static void IGF_appl_ivas( IGF_DEC_PRIVATE_DATA_HANDLE hPrivateData,     /**< in
         L_c = L_macNs_co( L_c, 0, 0, &Carry, &Overflow );
     }
     L_tmp = norm_llQ31( L_c, L_tmp, &shift ); // Q31
+#else
+    L_tmp = sum_array_norm( energyTmp, 24, &shift );
+#endif
     /* float: dE = (float)sqrt(dE / 24.f); basop: */
     shift = add( sub( shift, 4 ), dE_e ); /* x/24 = (x >> 4) * 1/1.5 */
     dE = Sqrt16norm( extract_h( L_tmp ), &shift );
diff --git a/lib_enc/arith_coder_enc_fx.c b/lib_enc/arith_coder_enc_fx.c
index a9955e6f69979a1c608ae6891d07a797f616826f..58125b81cafde7044d7fb0c02b05883a1d082edd 100644
--- a/lib_enc/arith_coder_enc_fx.c
+++ b/lib_enc/arith_coder_enc_fx.c
@@ -688,14 +688,21 @@ void tcx_arith_encode_envelope_fx(
     const Word8 *deadzone_flags;
     Word16 gamma_w, gamma_uw;
     Word16 hm_bits;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word32 L_tmp, L_tmp2;
+#else
+    Word32 L_tmp;
+    Word64 W_tmp2;
+#endif
     Word16 tmp;
     TCX_ENC_HANDLE hTcxEnc = st->hTcxEnc;
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
     move32();
     move32();
+#endif
 #endif
 
     assert( L_spec <= N_MAX_ARI );
@@ -780,10 +787,18 @@ void tcx_arith_encode_envelope_fx(
     move16();
 
     /* Multiply back the signs */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     L_tmp2 = L_deposit_l( 0 );
+#else
+    W_tmp2 = 0;
+#endif
     FOR( k = 0; k <= kMax; k++ )
     {
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         L_tmp2 = L_macNs_co( L_tmp2, q_spectrum[k], k, &Carry, &Overflow );
+#else
+        W_tmp2 = W_mac_16_16( W_tmp2, q_spectrum[k], k );
+#endif
 
         if ( signs[k] != 0 )
             L_tmp = L_mult( q_spectrum[k], -( 1 << ( 30 - SPEC_EXP_DEC ) ) );
@@ -797,7 +812,11 @@ void tcx_arith_encode_envelope_fx(
     set32_fx( spectrum + k, 0, sub( s_max( L_frame, L_spec ), k ) );
 
     /* noise filling seed */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     *nf_seed = extract_l( L_tmp2 );
+#else
+    *nf_seed = extract_l( W_extract_l( W_tmp2 ) );
+#endif
     move16();
 }
 
diff --git a/lib_enc/cod_tcx_fx.c b/lib_enc/cod_tcx_fx.c
index 3ab224a62b2eabae46f3c8227943db9ee044cf69..2d6b9fcb077b9e08b643f08dde38c78dc5f2e01d 100644
--- a/lib_enc/cod_tcx_fx.c
+++ b/lib_enc/cod_tcx_fx.c
@@ -1274,8 +1274,10 @@ void QuantizeSpectrum_fx(
     CONTEXT_HM_CONFIG *phm_cfg;
     TCX_ENC_HANDLE hTcxEnc = st->hTcxEnc;
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
+#endif
 #endif
 
     /* Stack memory is split between encoder and internal decoder to reduce max
@@ -1839,17 +1841,30 @@ void QuantizeSpectrum_fx(
 
             /* Save quantized Values */
             tmp32 = L_deposit_l( 0 );
+            move16();
+#ifdef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+            Word64 seed = 0;
+            move64();
+#endif
             FOR( i = 0; i < L_spec; i++ )
             {
                 spectrum[i] = L_mult( sqQ[i], 1 << ( 30 - SPEC_EXP_DEC ) );
                 move32();
                 /* noise filling seed */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
                 tmp32 = L_macNs_co( tmp32, abs_s( sqQ[i] ), i, &Carry, &Overflow );
+#else
+                seed = W_mac_16_16( seed, abs_s( sqQ[i] ), i );
+#endif
             }
             *spectrum_e = SPEC_EXP_DEC;
             move16();
 
+#ifdef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
+            nf_seed = extract_l( W_extract_l( seed ) ); // Q0
+#else
             nf_seed = extract_l( tmp32 );
+#endif
         }
         ELSE /* low rates: new arithmetic coder */
         {
@@ -2900,10 +2915,12 @@ void QuantizeTCXSpectrum_fx(
     Word16 att_fx = 0;
     move16();
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     move16();
     Flag Carry = 0;
     move16();
+#endif
 #endif
     /*-----------------------------------------------------------*
      * Init                                                      *
@@ -3527,7 +3544,11 @@ void QuantizeTCXSpectrum_fx(
             spectrum_fx[i] = L_mult( sqQ[i], 1 << ( 30 - SPEC_EXP_DEC ) );
             move32();
             /* noise filling seed */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
             tmp32 = L_macNs_co( tmp32, abs_s( sqQ[i] ), i, &Carry, &Overflow );
+#else
+            tmp32 = L_macNs( tmp32, abs_s( sqQ[i] ), i );
+#endif
         }
         *spectrum_e = SPEC_EXP_DEC;
         move16();
diff --git a/lib_enc/enc_acelp_fx.c b/lib_enc/enc_acelp_fx.c
index 2053a12932c98eae3e56db050da6d6886e9bc3fa..ec8efa841e96b1a093378b0e87ed04c18e02a304 100644
--- a/lib_enc/enc_acelp_fx.c
+++ b/lib_enc/enc_acelp_fx.c
@@ -2058,10 +2058,16 @@ static void E_ACELP_codearithp_fx( const Word16 v[] /*Q9*/, UWord32 *n /*Q0*/, U
 {
     Word16 k, nb_pulse, i, t, pos[NPMAXPT], posno;
     Word16 sign, m;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     UWord32 s;
+#else
+    UWord64 W_s;
+#endif
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
+#endif
     move32();
     move32();
 #endif
@@ -2087,7 +2093,11 @@ static void E_ACELP_codearithp_fx( const Word16 v[] /*Q9*/, UWord32 *n /*Q0*/, U
     }
 
     /* Iterate over the different pulse positions */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     s = L_deposit_l( 0 );
+#else
+    W_s = 0;
+#endif
     t = 0;
     move16();
     nb_pulse = 0;
@@ -2100,9 +2110,15 @@ static void E_ACELP_codearithp_fx( const Word16 v[] /*Q9*/, UWord32 *n /*Q0*/, U
         /* Code m-1 pulses */
         FOR( i = 1; i < m; ++i )
         {
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
             Carry = 0;
+#endif
             move32();
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
             s = L_add_co( s, pulsestostates[pos[k]][t], &Carry, &Overflow );
+#else
+            W_s = W_add( W_s, pulsestostates[pos[k]][t] );
+#endif
             t = add( t, 1 );
             if ( sub( t, NPMAXPT ) > 0 )
             {
@@ -2113,22 +2129,42 @@ static void E_ACELP_codearithp_fx( const Word16 v[] /*Q9*/, UWord32 *n /*Q0*/, U
         /* Code sign */
         /* We use L_add_c since we want to work with unsigned UWord32 */
         /* Therefore, we have to clear carry */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         Carry = 0;
+#endif
         move32();
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         s = L_lshl( s, 1 );
+#else
+        W_s = W_lshl( W_s, 1 );
+#endif
         if ( sign < 0 )
         {
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
             s = L_add_co( s, 1, &Carry, &Overflow );
+#else
+            W_s = W_add( W_s, 1 );
+#endif
         }
 
         /* Code last pulse */
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         Carry = 0;
+#endif
         move32();
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         s = L_add_co( s, pulsestostates[pos[k]][t], &Carry, &Overflow );
+#else
+        W_s = W_add( W_s, pulsestostates[pos[k]][t] );
+#endif
         t = add( t, 1 );
     }
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     *ps = s; /*Q0*/
+#else
+    *ps = (UWord32) W_s; /*Q0*/
+#endif
     move32();
     *n = L_deposit_l( 0 );
     if ( nb_pulse )
diff --git a/lib_enc/igf_enc_fx.c b/lib_enc/igf_enc_fx.c
old mode 100644
new mode 100755
index 2a96904e1ad651c9bdba754ee6ef004bee6d9d34..b6a1c66c202aff09bbe1d85d057a5ec8c58c4394
--- a/lib_enc/igf_enc_fx.c
+++ b/lib_enc/igf_enc_fx.c
@@ -369,7 +369,9 @@ void IGF_ErodeSpectrum( Word16 *highPassEner_exp,                        /**< ou
     Word32 highPassEner; /* Q31 */
     Word32 lastLine;
     Word32 nextLine;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word32 L_c;
+#endif
     Word32 highPassEner_Ovfl;
     Word16 s;
     Word16 tmploop;
@@ -383,11 +385,15 @@ void IGF_ErodeSpectrum( Word16 *highPassEner_exp,                        /**< ou
     Word16 tmp;
     Word32 L_tmp;
 
+#if !defined( FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW ) && !defined( ISSUE_1867_replace_overflow_libenc )
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
     Flag Overflow = 0;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Carry = 0;
+#endif
     move32();
     move32();
+#endif
 #endif
 
     hPrivateData = &hInstance->igfData;
@@ -420,19 +426,32 @@ void IGF_ErodeSpectrum( Word16 *highPassEner_exp,                        /**< ou
 
     IF( igfBgn > 0 )
     {
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         L_c = 0;
         move32();
+#else
+        Word64 W_highPassEner = 0;
+        move64();
+#endif
         FOR( i = 0; i < igfBgn; i++ )
         {
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
             Carry = 0;
             move32();
             highPassEner = L_add_co( highPassEner, Mpy_32_16_1( pPowerSpectrum[i], shl( i, 4 ) /*Q4*/ ) /*Q20, pPowerSpectrum_exp*/, &Carry, &Overflow );
             Overflow = 0;
             move32();
             L_c = L_macNs_co( L_c, 0, 0, &Carry, &Overflow );
+#else
+            W_highPassEner = W_add( W_highPassEner, W_deposit32_l( Mpy_32_16_1( pPowerSpectrum[i], shl( i, 4 ) /*Q4*/ ) ) /*Q20, pPowerSpectrum_exp*/ );
+#endif
         }
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         highPassEner = norm_llQ31( L_c, highPassEner, highPassEner_exp ); /*Q20, highPassEner_exp*/
+#else
+        highPassEner = w_norm_llQ31( W_highPassEner, highPassEner_exp ); /*Q20, highPassEner_exp*/
+#endif
         *highPassEner_exp = add( *highPassEner_exp, pPowerSpectrum_exp );
         move16();
         test();
@@ -896,16 +915,22 @@ Word16 IGF_getSFM(                           /**< out: Q15| SFM value
     Word16 invDenom_exp, numf_exp;
     Word16 numf;
     Word32 SFM32;
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Word32 L_c;
+#endif
     Word16 invDenom, SFM;
 #ifdef BASOP_NOGLOB_DECLARE_LOCAL
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     Flag Overflow = 0;
     Flag Carry = 0;
+#endif
     move32();
     move32();
 #endif
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     L_c = 0;
+#endif
     move32();
     num = 0;
     move32();
@@ -916,6 +941,7 @@ Word16 IGF_getSFM(                           /**< out: Q15| SFM value
     SFM = 32767 /*1.0f Q15*/;
     move16();
 
+    Word64 W_denom = W_deposit32_l( denom );
     FOR( i = start; i < stop; i++ )
     {
         /*ln(x * 2^-Qx * 2^xExp) = ln(x) - Qx + xExp*/
@@ -935,15 +961,23 @@ Word16 IGF_getSFM(                           /**< out: Q15| SFM value
         n = s_max( 0, n );
         num = L_add( num, L_deposit_l( n ) ); /*Q0*/
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
         Carry = 0;
         move32();
         denom = L_add_co( energy[i], denom, &Carry, &Overflow );
         Overflow = 0;
         move32();
         L_c = L_macNs_co( L_c, 0, 0, &Carry, &Overflow );
+#else
+        W_denom = W_add( W_deposit32_l( energy[i] ), W_denom );
+#endif
     }
 
+#ifndef FIX_ISSUE_1965_REPLACE_CARRY_OVERFLOW
     denom = norm_llQ31( L_c, denom, &denom_exp ); /*Q31*/
+#else
+    denom = w_norm_llQ31( W_denom, &denom_exp ); /*Q31*/
+#endif
     denom_exp = add( denom_exp, *energy_exp );
 
     /* calculate SFM only if signal is present */