diff --git a/src/iss/arch/riscv_hart_m_p.h b/src/iss/arch/riscv_hart_m_p.h
index 6abd9d0..b8f63ca 100644
--- a/src/iss/arch/riscv_hart_m_p.h
+++ b/src/iss/arch/riscv_hart_m_p.h
@@ -212,9 +212,9 @@ public:
         csr[addr & csr.page_addr_mask] = val;
     }
 
-//    void set_irq_num(unsigned i) {
-//        mcause_max_irq=1<<util::ilog2(i);
-//    }
+    void set_irq_num(unsigned i) {
+        mcause_max_irq=1<<util::ilog2(i);
+    }
 protected:
     struct riscv_instrumentation_if : public iss::instrumentation_if {
 
diff --git a/src/iss/arch/riscv_hart_mu_p.h b/src/iss/arch/riscv_hart_mu_p.h
index 2a6c29e..7ed92ea 100644
--- a/src/iss/arch/riscv_hart_mu_p.h
+++ b/src/iss/arch/riscv_hart_mu_p.h
@@ -227,9 +227,9 @@ public:
         csr[addr & csr.page_addr_mask] = val;
     }
 
-//    void set_irq_num(unsigned i) {
-//        mcause_max_irq=1<<util::ilog2(i);
-//    }
+    void set_irq_num(unsigned i) {
+        mcause_max_irq=1<<util::ilog2(i);
+    }
 protected:
     struct riscv_instrumentation_if : public iss::instrumentation_if {