diff --git a/src/iss/arch/riscv_hart_m_p.h b/src/iss/arch/riscv_hart_m_p.h
index 11b3739..890bf6c 100644
--- a/src/iss/arch/riscv_hart_m_p.h
+++ b/src/iss/arch/riscv_hart_m_p.h
@@ -252,8 +252,11 @@ public:
         return 0b100010001000; // only machine mode is supported
     }
 
+    constexpr bool has_compressed() {
+        return traits<BASE>::MISA_VAL&0b0100;
+    }
     constexpr reg_t get_pc_mask() {
-        return traits<BASE>::MISA_VAL&0b0100?~1:~3;
+        return has_compressed()?~1:~3;
     }
 
     riscv_hart_m_p(feature_config cfg = feature_config{});
@@ -435,7 +438,7 @@ riscv_hart_m_p<BASE, FEAT>::riscv_hart_m_p(feature_config cfg)
         csr_rd_cb[addr] = &this_class::read_null;
         csr_wr_cb[addr] = &this_class::write_csr_reg;
     }
-    for (unsigned addr = mhpmcounter3h; addr <= mhpmcounter31h; ++addr){
+    if(traits<BASE>::XLEN==32) for (unsigned addr = mhpmcounter3h; addr <= mhpmcounter31h; ++addr){
         csr_rd_cb[addr] = &this_class::read_null;
         csr_wr_cb[addr] = &this_class::write_csr_reg;
     }
@@ -446,7 +449,7 @@ riscv_hart_m_p<BASE, FEAT>::riscv_hart_m_p(feature_config cfg)
     for (unsigned addr = hpmcounter3; addr <= hpmcounter31; ++addr){
         csr_rd_cb[addr] = &this_class::read_null;
     }
-    for (unsigned addr = hpmcounter3h; addr <= hpmcounter31h; ++addr){
+    if(traits<BASE>::XLEN==32) for (unsigned addr = hpmcounter3h; addr <= hpmcounter31h; ++addr){
         csr_rd_cb[addr] = &this_class::read_null;
         //csr_wr_cb[addr] = &this_class::write_csr_reg;
     }
@@ -469,12 +472,12 @@ riscv_hart_m_p<BASE, FEAT>::riscv_hart_m_p(feature_config cfg)
 
     csr_rd_cb[mcycle] = &this_class::read_cycle;
     csr_wr_cb[mcycle] = &this_class::write_cycle;
-    csr_rd_cb[mcycleh] = &this_class::read_cycle;
-    csr_wr_cb[mcycleh] = &this_class::write_cycle;
+    if(traits<BASE>::XLEN==32) csr_rd_cb[mcycleh] = &this_class::read_cycle;
+    if(traits<BASE>::XLEN==32) csr_wr_cb[mcycleh] = &this_class::write_cycle;
     csr_rd_cb[minstret] = &this_class::read_instret;
     csr_wr_cb[minstret] = &this_class::write_instret;
-    csr_rd_cb[minstreth] = &this_class::read_instret;
-    csr_wr_cb[minstreth] = &this_class::write_instret;
+    if(traits<BASE>::XLEN==32) csr_rd_cb[minstreth] = &this_class::read_instret;
+    if(traits<BASE>::XLEN==32) csr_wr_cb[minstreth] = &this_class::write_instret;
     csr_rd_cb[mstatus] = &this_class::read_status;
     csr_wr_cb[mstatus] = &this_class::write_status;
     csr_rd_cb[mcause] = &this_class::read_cause;
@@ -633,7 +636,7 @@ iss::status riscv_hart_m_p<BASE, FEAT>::read(const address_type type, const acce
     try {
         switch (space) {
         case traits<BASE>::MEM: {
-            auto alignment = is_fetch(access)? (traits<BASE>::MISA_VAL&0x100? 2 : 4) : length;
+            auto alignment = is_fetch(access)? (has_compressed()? 2 : 4) : length;
             if (unlikely(is_fetch(access) && (addr&(alignment-1)))) {
                 fault_data = addr;
                 if (is_debug(access)) throw trap_access(0, addr);
@@ -869,7 +872,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_m_p<BASE, FEAT>
     if (addr == mcycle) {
         val = static_cast<reg_t>(cycle_val);
     } else if (addr == mcycleh) {
-        if (sizeof(typename traits<BASE>::reg_t) != 4) return iss::Err;
         val = static_cast<reg_t>(cycle_val >> 32);
     }
     return iss::Ok;
@@ -877,8 +879,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_m_p<BASE, FEAT>
 
 template <typename BASE, features_e FEAT> iss::status riscv_hart_m_p<BASE, FEAT>::write_cycle(unsigned addr, reg_t val) {
     if (sizeof(typename traits<BASE>::reg_t) != 4) {
-        if (addr == mcycleh)
-            return iss::Err;
         mcycle_csr = static_cast<uint64_t>(val);
     } else {
         if (addr == mcycle) {
@@ -895,7 +895,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_m_p<BASE, FEAT>
     if ((addr&0xff) == (minstret&0xff)) {
         val = static_cast<reg_t>(this->instret);
     } else if ((addr&0xff) == (minstreth&0xff)) {
-        if (sizeof(typename traits<BASE>::reg_t) != 4) return iss::Err;
         val = static_cast<reg_t>(this->instret >> 32);
     }
     return iss::Ok;
@@ -903,8 +902,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_m_p<BASE, FEAT>
 
 template <typename BASE, features_e FEAT> iss::status riscv_hart_m_p<BASE, FEAT>::write_instret(unsigned addr, reg_t val) {
     if (sizeof(typename traits<BASE>::reg_t) != 4) {
-        if ((addr&0xff) == (minstreth&0xff))
-            return iss::Err;
         this->instret = static_cast<uint64_t>(val);
     } else {
         if ((addr&0xff) == (minstret&0xff)) {
@@ -1244,7 +1241,7 @@ template <typename BASE, features_e FEAT> uint64_t riscv_hart_m_p<BASE, FEAT>::e
             csr[mtval] = static_cast<reg_t>(addr);
             break;
         case 2:
-            csr[mtval] = (instr & 0x3)==3?instr:instr&0xffff;
+            csr[mtval] = (!has_compressed() || (instr & 0x3)==3)?instr:instr&0xffff;
             break;
         case 3:
             if((FEAT & FEAT_DEBUG) && (csr[dcsr] & 0x8000)) {
diff --git a/src/iss/arch/riscv_hart_mu_p.h b/src/iss/arch/riscv_hart_mu_p.h
index 1b828fe..c896701 100644
--- a/src/iss/arch/riscv_hart_mu_p.h
+++ b/src/iss/arch/riscv_hart_mu_p.h
@@ -193,8 +193,11 @@ public:
         return m[mode];
     }
 
+    constexpr bool has_compressed() {
+        return traits<BASE>::MISA_VAL&0b0100;
+    }
     constexpr reg_t get_pc_mask() {
-        return traits<BASE>::MISA_VAL&0b0100?~1:~3;
+        return has_compressed()?~1:~3;
     }
 
     riscv_hart_mu_p(feature_config cfg = feature_config{});
@@ -379,7 +382,7 @@ riscv_hart_mu_p<BASE, FEAT>::riscv_hart_mu_p(feature_config cfg)
         csr_rd_cb[addr] = &this_class::read_null;
         csr_wr_cb[addr] = &this_class::write_csr_reg;
     }
-    for (unsigned addr = mhpmcounter3h; addr <= mhpmcounter31h; ++addr){
+    if(traits<BASE>::XLEN==32) for (unsigned addr = mhpmcounter3h; addr <= mhpmcounter31h; ++addr){
         csr_rd_cb[addr] = &this_class::read_null;
         csr_wr_cb[addr] = &this_class::write_csr_reg;
     }
@@ -390,7 +393,7 @@ riscv_hart_mu_p<BASE, FEAT>::riscv_hart_mu_p(feature_config cfg)
     for (unsigned addr = hpmcounter3; addr <= hpmcounter31; ++addr){
         csr_rd_cb[addr] = &this_class::read_null;
     }
-    for (unsigned addr = hpmcounter3h; addr <= hpmcounter31h; ++addr){
+    if(traits<BASE>::XLEN==32) for (unsigned addr = hpmcounter3h; addr <= hpmcounter31h; ++addr){
         csr_rd_cb[addr] = &this_class::read_null;
         //csr_wr_cb[addr] = &this_class::write_csr_reg;
     }
@@ -414,12 +417,12 @@ riscv_hart_mu_p<BASE, FEAT>::riscv_hart_mu_p(feature_config cfg)
 
     csr_rd_cb[mcycle] = &this_class::read_cycle;
     csr_wr_cb[mcycle] = &this_class::write_cycle;
-    csr_rd_cb[mcycleh] = &this_class::read_cycle;
-    csr_wr_cb[mcycleh] = &this_class::write_cycle;
+    if(traits<BASE>::XLEN==32) csr_rd_cb[mcycleh] = &this_class::read_cycle;
+    if(traits<BASE>::XLEN==32) csr_wr_cb[mcycleh] = &this_class::write_cycle;
     csr_rd_cb[minstret] = &this_class::read_instret;
     csr_wr_cb[minstret] = &this_class::write_instret;
-    csr_rd_cb[minstreth] = &this_class::read_instret;
-    csr_wr_cb[minstreth] = &this_class::write_instret;
+    if(traits<BASE>::XLEN==32) csr_rd_cb[minstreth] = &this_class::read_instret;
+    if(traits<BASE>::XLEN==32) csr_wr_cb[minstreth] = &this_class::write_instret;
     csr_rd_cb[mstatus] = &this_class::read_status;
     csr_wr_cb[mstatus] = &this_class::write_status;
     csr_rd_cb[mcause] = &this_class::read_cause;
@@ -713,7 +716,7 @@ iss::status riscv_hart_mu_p<BASE, FEAT>::read(const address_type type, const acc
                     return iss::Err;
                 }
             }
-            auto alignment = is_fetch(access)? (traits<BASE>::MISA_VAL&0x100? 2 : 4) : length;
+            auto alignment = is_fetch(access)? (has_compressed()? 2 : 4) : length;
             if (unlikely(is_fetch(access) && (addr&(alignment-1)))) {
                 fault_data = addr;
                 if (is_debug(access)) throw trap_access(0, addr);
@@ -957,7 +960,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_mu_p<BASE, FEAT
     if (addr == mcycle) {
         val = static_cast<reg_t>(cycle_val);
     } else if (addr == mcycleh) {
-        if (sizeof(typename traits<BASE>::reg_t) != 4) return iss::Err;
         val = static_cast<reg_t>(cycle_val >> 32);
     }
     return iss::Ok;
@@ -965,8 +967,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_mu_p<BASE, FEAT
 
 template <typename BASE, features_e FEAT> iss::status riscv_hart_mu_p<BASE, FEAT>::write_cycle(unsigned addr, reg_t val) {
     if (sizeof(typename traits<BASE>::reg_t) != 4) {
-        if (addr == mcycleh)
-            return iss::Err;
         mcycle_csr = static_cast<uint64_t>(val);
     } else {
         if (addr == mcycle) {
@@ -983,7 +983,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_mu_p<BASE, FEAT
     if ((addr&0xff) == (minstret&0xff)) {
         val = static_cast<reg_t>(this->instret);
     } else if ((addr&0xff) == (minstreth&0xff)) {
-        if (sizeof(typename traits<BASE>::reg_t) != 4) return iss::Err;
         val = static_cast<reg_t>(this->instret >> 32);
     }
     return iss::Ok;
@@ -991,8 +990,6 @@ template <typename BASE, features_e FEAT> iss::status riscv_hart_mu_p<BASE, FEAT
 
 template <typename BASE, features_e FEAT> iss::status riscv_hart_mu_p<BASE, FEAT>::write_instret(unsigned addr, reg_t val) {
     if (sizeof(typename traits<BASE>::reg_t) != 4) {
-        if ((addr&0xff) == (minstreth&0xff))
-            return iss::Err;
         this->instret = static_cast<uint64_t>(val);
     } else {
         if ((addr&0xff) == (minstret&0xff)) {
@@ -1369,7 +1366,7 @@ template <typename BASE, features_e FEAT> uint64_t riscv_hart_mu_p<BASE, FEAT>::
             csr[utval | (new_priv << 8)] = static_cast<reg_t>(addr);
             break;
         case 2:
-            csr[utval | (new_priv << 8)] = (instr & 0x3)==3?instr:instr&0xffff;
+            csr[utval | (new_priv << 8)] = (!has_compressed() || (instr & 0x3)==3)?instr:instr&0xffff;
             break;
         case 3:
             if((FEAT & FEAT_DEBUG) && (csr[dcsr] & 0x8000)) {