diff --git a/gen_input/templates/asmjit/CORENAME.cpp.gtl b/gen_input/templates/asmjit/CORENAME.cpp.gtl
index eb7cb3d..55ab9d6 100644
--- a/gen_input/templates/asmjit/CORENAME.cpp.gtl
+++ b/gen_input/templates/asmjit/CORENAME.cpp.gtl
@@ -347,7 +347,7 @@ void vm_impl<ARCH>::gen_block_epilogue(jit_holder& jh){
     mov(cc, current_next_pc, get_ptr_for(jh, traits::NEXT_PC));
     mov(cc, jh.next_pc, current_next_pc);
 
-    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), std::numeric_limits<uint32_t>::max());
+    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(UNKNOWN_JUMP));
     cc.ret(jh.next_pc);
 }
 template <typename ARCH>
diff --git a/gen_input/templates/llvm/CORENAME.cpp.gtl b/gen_input/templates/llvm/CORENAME.cpp.gtl
index c48ffe0..3d3ebfb 100644
--- a/gen_input/templates/llvm/CORENAME.cpp.gtl
+++ b/gen_input/templates/llvm/CORENAME.cpp.gtl
@@ -338,7 +338,7 @@ template <typename ARCH>
 void vm_impl<ARCH>::gen_leave_trap(unsigned lvl) {
     std::vector<Value *> args{ this->core_ptr, ConstantInt::get(getContext(), APInt(64, lvl)) };
     this->builder.CreateCall(this->mod->getFunction("leave_trap"), args);
-    this->builder.CreateStore(this->gen_const(32U, std::numeric_limits<uint32_t>::max()), get_reg_ptr(traits::LAST_BRANCH), false);
+    this->builder.CreateStore(this->gen_const(32U, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
 }
 
 template <typename ARCH>
@@ -366,7 +366,7 @@ void vm_impl<ARCH>::gen_trap_behavior(BasicBlock *trap_blk) {
                                 this->adj_to64(cur_pc_val),
                               this->adj_to64(this->builder.CreateLoad(this->get_type(64),this->tval))};
     this->builder.CreateCall(this->mod->getFunction("enter_trap"), args);
-    this->builder.CreateStore(this->gen_const(32U, std::numeric_limits<uint32_t>::max()), get_reg_ptr(traits::LAST_BRANCH), false);
+    this->builder.CreateStore(this->gen_const(32U, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
 
     auto *trap_addr_val = this->builder.CreateLoad(this->get_typeptr(traits::NEXT_PC), get_reg_ptr(traits::NEXT_PC), false);
     this->builder.CreateRet(trap_addr_val);
diff --git a/gen_input/templates/tcc/CORENAME.cpp.gtl b/gen_input/templates/tcc/CORENAME.cpp.gtl
index 3480e56..a6e2f64 100644
--- a/gen_input/templates/tcc/CORENAME.cpp.gtl
+++ b/gen_input/templates/tcc/CORENAME.cpp.gtl
@@ -302,13 +302,12 @@ vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt,
 
 template <typename ARCH> void vm_impl<ARCH>::gen_raise_trap(tu_builder& tu, uint16_t trap_id, uint16_t cause) {
     tu("  *trap_state = {:#x};", 0x80 << 24 | (cause << 16) | trap_id);
-    tu.store(traits::NEXT_PC, tu.constant(std::numeric_limits<uint32_t>::max(), 32));
 }
 
 template <typename ARCH> void vm_impl<ARCH>::gen_leave_trap(tu_builder& tu, unsigned lvl) {
     tu("leave_trap(core_ptr, {});", lvl);
     tu.store(traits::NEXT_PC, tu.read_mem(traits::CSR, (lvl << 8) + 0x41, traits::XLEN));
-    tu.store(traits::LAST_BRANCH, tu.constant(std::numeric_limits<uint32_t>::max(), 32));
+    tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP), 32));
 }
 
 template <typename ARCH> void vm_impl<ARCH>::gen_wait(tu_builder& tu, unsigned type) {
@@ -325,7 +324,7 @@ template <typename ARCH> void vm_impl<ARCH>::gen_trap_behavior(tu_builder& tu) {
     tu("trap_entry:");
     this->gen_sync(tu, POST_SYNC, -1);    
     tu("enter_trap(core_ptr, *trap_state, *pc, tval);");
-    tu.store(traits::LAST_BRANCH, tu.constant(std::numeric_limits<uint32_t>::max(),32));
+    tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP),32));
     tu("return *next_pc;");
 }
 
diff --git a/src/vm/asmjit/vm_tgc5c.cpp b/src/vm/asmjit/vm_tgc5c.cpp
index da56508..df92a8e 100644
--- a/src/vm/asmjit/vm_tgc5c.cpp
+++ b/src/vm/asmjit/vm_tgc5c.cpp
@@ -440,6 +440,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rd>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -456,7 +457,7 @@ private:
                 }
                 auto PC_val_v = new_pc;
                 mov(cc, jh.next_pc, PC_val_v);
-                mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
             }
         }
         auto returnValue = BRANCH;
@@ -498,6 +499,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rd>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -525,7 +527,7 @@ private:
                     }
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(UNKNOWN_JUMP));
                 }
             cc.bind(label_merge);
         }
@@ -568,6 +570,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -585,7 +588,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
                 }
             }
             cc.bind(label_merge);
@@ -629,6 +632,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -646,7 +650,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
                 }
             }
             cc.bind(label_merge);
@@ -690,6 +694,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -709,7 +714,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
                 }
             }
             cc.bind(label_merge);
@@ -753,6 +758,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -772,7 +778,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
                 }
             }
             cc.bind(label_merge);
@@ -816,6 +822,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -833,7 +840,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
                 }
             }
             cc.bind(label_merge);
@@ -877,6 +884,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -894,7 +902,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     mov(cc, jh.next_pc, PC_val_v);
-                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+                    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
                 }
             }
             cc.bind(label_merge);
@@ -2387,6 +2395,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         gen_raise(jh, 0, 11);
         auto returnValue = TRAP;
         
@@ -2423,6 +2432,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         gen_raise(jh, 0, 3);
         auto returnValue = TRAP;
         
@@ -2459,6 +2469,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         gen_leave(jh, 3);
         auto returnValue = TRAP;
         
@@ -3629,11 +3640,12 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         mov(cc, get_ptr_for(jh, traits::X0+ 1),
               (uint32_t)(PC+2));
         auto PC_val_v = (uint32_t)(PC+(int16_t)sext<12>(imm));
         mov(cc, jh.next_pc, PC_val_v);
-        mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+        mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
         auto returnValue = BRANCH;
         
         gen_sync(jh, POST_SYNC, 62);
@@ -4148,9 +4160,10 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         auto PC_val_v = (uint32_t)(PC+(int16_t)sext<12>(imm));
         mov(cc, jh.next_pc, PC_val_v);
-        mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+        mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
         auto returnValue = BRANCH;
         
         gen_sync(jh, POST_SYNC, 74);
@@ -4189,6 +4202,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         auto label_merge = cc.newLabel();
         cmp(cc, gen_operation(cc, eq, load_reg_from_mem(jh, traits::X0 + rs1+8), 0)
         ,0);
@@ -4196,7 +4210,7 @@ private:
         {
             auto PC_val_v = (uint32_t)(PC+(int16_t)sext<9>(imm));
             mov(cc, jh.next_pc, PC_val_v);
-            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
         }
         cc.bind(label_merge);
         auto returnValue = BRANCH;
@@ -4237,6 +4251,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         auto label_merge = cc.newLabel();
         cmp(cc, gen_operation(cc, ne, load_reg_from_mem(jh, traits::X0 + rs1+8), 0)
         ,0);
@@ -4244,7 +4259,7 @@ private:
         {
             auto PC_val_v = (uint32_t)(PC+(int16_t)sext<9>(imm));
             mov(cc, jh.next_pc, PC_val_v);
-            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(KNOWN_JUMP));
         }
         cc.bind(label_merge);
         auto returnValue = BRANCH;
@@ -4429,12 +4444,13 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs1&&rs1<static_cast<uint32_t>(traits::RFS)){
             auto addr_mask = (uint32_t)- 2;
             auto PC_val_v = gen_operation(cc, band, load_reg_from_mem(jh, traits::X0 + rs1%static_cast<uint32_t>(traits::RFS)), addr_mask)
             ;
             mov(cc, jh.next_pc, PC_val_v);
-            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(UNKNOWN_JUMP));
         }
         else{
             gen_raise(jh, 0, 2);
@@ -4561,6 +4577,7 @@ private:
         gen_instr_prologue(jh);
         cc.comment("//behavior:");
         /*generate behavior*/
+        mov(jh.cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(NO_JUMP));
         if(rs1>=static_cast<uint32_t>(traits::RFS)){
             gen_raise(jh, 0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -4572,7 +4589,7 @@ private:
             auto PC_val_v = gen_operation(cc, band, new_pc, addr_mask)
             ;
             mov(cc, jh.next_pc, PC_val_v);
-            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), 32U);
+            mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(UNKNOWN_JUMP));
         }
         auto returnValue = BRANCH;
         
@@ -4870,7 +4887,7 @@ void vm_impl<ARCH>::gen_block_epilogue(jit_holder& jh){
     mov(cc, current_next_pc, get_ptr_for(jh, traits::NEXT_PC));
     mov(cc, jh.next_pc, current_next_pc);
 
-    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), std::numeric_limits<uint32_t>::max());
+    mov(cc, get_ptr_for(jh, traits::LAST_BRANCH), static_cast<int>(UNKNOWN_JUMP));
     cc.ret(jh.next_pc);
 }
 template <typename ARCH>
diff --git a/src/vm/llvm/vm_tgc5c.cpp b/src/vm/llvm/vm_tgc5c.cpp
index 7fda2bb..bd86bb8 100644
--- a/src/vm/llvm/vm_tgc5c.cpp
+++ b/src/vm/llvm/vm_tgc5c.cpp
@@ -449,6 +449,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rd>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -465,7 +466,7 @@ private:
                 }
                 auto PC_val_v = new_pc;
                 this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
             }
         }
         bb = this->leave_blk;
@@ -505,6 +506,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rd>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -541,7 +543,7 @@ private:
                 }
                 auto PC_val_v = new_pc;
                 this->builder.CreateStore(PC_val_v, get_reg_ptr(traits::NEXT_PC), false);                            
-                this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                this->builder.CreateStore(this->gen_const(32, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
             }
             this->builder.CreateBr(bb_merge);
             this->builder.SetInsertPoint(bb_merge);
@@ -583,6 +585,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -602,7 +605,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                    this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                    this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
                 }
             }
             this->builder.CreateBr(bb_merge);
@@ -645,6 +648,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -664,7 +668,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                    this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                    this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
                 }
             }
             this->builder.CreateBr(bb_merge);
@@ -707,6 +711,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -730,7 +735,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                    this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                    this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
                 }
             }
             this->builder.CreateBr(bb_merge);
@@ -773,6 +778,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -796,7 +802,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                    this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                    this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
                 }
             }
             this->builder.CreateBr(bb_merge);
@@ -839,6 +845,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -858,7 +865,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                    this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                    this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
                 }
             }
             this->builder.CreateBr(bb_merge);
@@ -901,6 +908,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs2>=static_cast<uint32_t>(traits::RFS)||rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -920,7 +928,7 @@ private:
                 else{
                     auto PC_val_v = new_pc;
                     this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-                    this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+                    this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
                 }
             }
             this->builder.CreateBr(bb_merge);
@@ -2431,6 +2439,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         this->gen_raise_trap(0, 11);
         bb = this->leave_blk;
         auto returnValue = std::make_tuple(TRAP,nullptr);
@@ -2465,6 +2474,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         this->gen_raise_trap(0, 3);
         bb = this->leave_blk;
         auto returnValue = std::make_tuple(TRAP,nullptr);
@@ -2499,6 +2509,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         this->gen_leave_trap(3);
         bb = this->leave_blk;
         auto returnValue = std::make_tuple(TRAP,nullptr);
@@ -3746,12 +3757,13 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         this->builder.CreateStore(
              this->gen_const(32,(uint32_t)(PC+2)),
              get_reg_ptr(1 + traits::X0), false);
         auto PC_val_v = (uint32_t)(PC+(int16_t)sext<12>(imm));
         this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-        this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+        this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         bb = this->leave_blk;
         auto returnValue = std::make_tuple(BRANCH,nullptr);
         
@@ -4276,9 +4288,10 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         auto PC_val_v = (uint32_t)(PC+(int16_t)sext<12>(imm));
         this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-        this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+        this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         bb = this->leave_blk;
         auto returnValue = std::make_tuple(BRANCH,nullptr);
         
@@ -4315,6 +4328,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         auto bb_merge = BasicBlock::Create(this->mod->getContext(), "bb_merge", this->func, this->leave_blk);
         auto bb_then = BasicBlock::Create(this->mod->getContext(), "bb_then", this->func, bb_merge);
         this->builder.CreateCondBr(this->gen_bool(this->builder.CreateICmp(ICmpInst::ICMP_EQ,
@@ -4325,7 +4339,7 @@ private:
         {
             auto PC_val_v = (uint32_t)(PC+(int16_t)sext<9>(imm));
             this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-            this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+            this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         }
         this->builder.CreateBr(bb_merge);
         this->builder.SetInsertPoint(bb_merge);
@@ -4365,6 +4379,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         auto bb_merge = BasicBlock::Create(this->mod->getContext(), "bb_merge", this->func, this->leave_blk);
         auto bb_then = BasicBlock::Create(this->mod->getContext(), "bb_then", this->func, bb_merge);
         this->builder.CreateCondBr(this->gen_bool(this->builder.CreateICmp(ICmpInst::ICMP_NE,
@@ -4375,7 +4390,7 @@ private:
         {
             auto PC_val_v = (uint32_t)(PC+(int16_t)sext<9>(imm));
             this->builder.CreateStore(this->gen_const(32,PC_val_v), get_reg_ptr(traits::NEXT_PC), false);
-            this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+            this->builder.CreateStore(this->gen_const(32, static_cast<int>(KNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         }
         this->builder.CreateBr(bb_merge);
         this->builder.SetInsertPoint(bb_merge);
@@ -4563,13 +4578,14 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs1&&rs1<static_cast<uint32_t>(traits::RFS)){ auto addr_mask =(uint32_t)- 2;
         auto PC_val_v = this->builder.CreateAnd(
            this->gen_reg_load(rs1%static_cast<uint32_t>(traits::RFS)+ traits::X0, 0),
            this->gen_const(32,addr_mask))
         ;
         this->builder.CreateStore(PC_val_v, get_reg_ptr(traits::NEXT_PC), false);                            
-        this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+        this->builder.CreateStore(this->gen_const(32, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         }
         else{
             this->gen_raise_trap(0, 2);
@@ -4694,6 +4710,7 @@ private:
         
         this->gen_instr_prologue();
         /*generate behavior*/
+        this->builder.CreateStore(this->gen_const(32U, static_cast<int>(NO_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         if(rs1>=static_cast<uint32_t>(traits::RFS)) {
             this->gen_raise_trap(0, static_cast<int32_t>(traits::RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -4708,7 +4725,7 @@ private:
                this->gen_const(32,addr_mask))
             ;
             this->builder.CreateStore(PC_val_v, get_reg_ptr(traits::NEXT_PC), false);                            
-            this->builder.CreateStore(this->gen_const(32,2U), get_reg_ptr(traits::LAST_BRANCH), false);
+            this->builder.CreateStore(this->gen_const(32, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
         }
         bb = this->leave_blk;
         auto returnValue = std::make_tuple(BRANCH,nullptr);
@@ -4987,7 +5004,7 @@ template <typename ARCH>
 void vm_impl<ARCH>::gen_leave_trap(unsigned lvl) {
     std::vector<Value *> args{ this->core_ptr, ConstantInt::get(getContext(), APInt(64, lvl)) };
     this->builder.CreateCall(this->mod->getFunction("leave_trap"), args);
-    this->builder.CreateStore(this->gen_const(32U, std::numeric_limits<uint32_t>::max()), get_reg_ptr(traits::LAST_BRANCH), false);
+    this->builder.CreateStore(this->gen_const(32U, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
 }
 
 template <typename ARCH>
@@ -5015,7 +5032,7 @@ void vm_impl<ARCH>::gen_trap_behavior(BasicBlock *trap_blk) {
                                 this->adj_to64(cur_pc_val),
                               this->adj_to64(this->builder.CreateLoad(this->get_type(64),this->tval))};
     this->builder.CreateCall(this->mod->getFunction("enter_trap"), args);
-    this->builder.CreateStore(this->gen_const(32U, std::numeric_limits<uint32_t>::max()), get_reg_ptr(traits::LAST_BRANCH), false);
+    this->builder.CreateStore(this->gen_const(32U, static_cast<int>(UNKNOWN_JUMP)), get_reg_ptr(traits::LAST_BRANCH), false);
 
     auto *trap_addr_val = this->builder.CreateLoad(this->get_typeptr(traits::NEXT_PC), get_reg_ptr(traits::NEXT_PC), false);
     this->builder.CreateRet(trap_addr_val);
diff --git a/src/vm/tcc/vm_tgc5c.cpp b/src/vm/tcc/vm_tgc5c.cpp
index 1c23d54..afdfbc6 100644
--- a/src/vm/tcc/vm_tgc5c.cpp
+++ b/src/vm/tcc/vm_tgc5c.cpp
@@ -422,6 +422,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rd>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -437,7 +438,7 @@ private:
         		}
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         }
         auto returnValue = std::make_tuple(BRANCH);
@@ -468,6 +469,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rd>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -490,7 +492,7 @@ private:
         	}
         	auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         	tu.store(traits::NEXT_PC, PC_val_v);
-        	tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        	tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP), 2));
         	tu.close_scope();
         }
         auto returnValue = std::make_tuple(BRANCH);
@@ -521,6 +523,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs2>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -535,7 +538,7 @@ private:
         	else{
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         	tu.close_scope();
         }
@@ -567,6 +570,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs2>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -581,7 +585,7 @@ private:
         	else{
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         	tu.close_scope();
         }
@@ -613,6 +617,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs2>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -627,7 +632,7 @@ private:
         	else{
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         	tu.close_scope();
         }
@@ -659,6 +664,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs2>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -673,7 +679,7 @@ private:
         	else{
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         	tu.close_scope();
         }
@@ -705,6 +711,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs2>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -719,7 +726,7 @@ private:
         	else{
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         	tu.close_scope();
         }
@@ -751,6 +758,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs2>=static_cast<uint32_t>(traits:: RFS)||rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -765,7 +773,7 @@ private:
         	else{
         		auto PC_val_v = tu.assignment("PC_val", new_pc,32);
         		tu.store(traits::NEXT_PC, PC_val_v);
-        		tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        		tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         	}
         	tu.close_scope();
         }
@@ -1885,6 +1893,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         this->gen_raise_trap(tu, 0, 11);
         auto returnValue = std::make_tuple(TRAP);
         
@@ -1908,6 +1917,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         this->gen_raise_trap(tu, 0, 3);
         auto returnValue = std::make_tuple(TRAP);
         
@@ -1931,6 +1941,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         this->gen_leave_trap(tu, 3);
         auto returnValue = std::make_tuple(TRAP);
         
@@ -2810,11 +2821,12 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         tu.store(1 + traits::X0,
               tu.constant((uint32_t)(PC+2),32));
         auto PC_val_v = tu.assignment("PC_val", (uint32_t)(PC+(int16_t)sext<12>(imm)),32);
         tu.store(traits::NEXT_PC, PC_val_v);
-        tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         auto returnValue = std::make_tuple(BRANCH);
         
         tu.close_scope();
@@ -3195,9 +3207,10 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         auto PC_val_v = tu.assignment("PC_val", (uint32_t)(PC+(int16_t)sext<12>(imm)),32);
         tu.store(traits::NEXT_PC, PC_val_v);
-        tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         auto returnValue = std::make_tuple(BRANCH);
         
         tu.close_scope();
@@ -3225,12 +3238,13 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         tu.open_if(tu.icmp(ICmpInst::ICMP_EQ,
            tu.load(rs1+8+ traits::X0, 0),
            tu.constant(0,8)));
         auto PC_val_v = tu.assignment("PC_val", (uint32_t)(PC+(int16_t)sext<9>(imm)),32);
         tu.store(traits::NEXT_PC, PC_val_v);
-        tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         tu.close_scope();
         auto returnValue = std::make_tuple(BRANCH);
         
@@ -3259,12 +3273,13 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         tu.open_if(tu.icmp(ICmpInst::ICMP_NE,
            tu.load(rs1+8+ traits::X0, 0),
            tu.constant(0,8)));
         auto PC_val_v = tu.assignment("PC_val", (uint32_t)(PC+(int16_t)sext<9>(imm)),32);
         tu.store(traits::NEXT_PC, PC_val_v);
-        tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(KNOWN_JUMP), 2));
         tu.close_scope();
         auto returnValue = std::make_tuple(BRANCH);
         
@@ -3403,12 +3418,13 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs1&&rs1<static_cast<uint32_t>(traits:: RFS)){ auto addr_mask = (uint32_t)- 2;
         auto PC_val_v = tu.assignment("PC_val", tu.bitwise_and(
            tu.load(rs1%static_cast<uint32_t>(traits:: RFS)+ traits::X0, 0),
            tu.constant(addr_mask,32)),32);
         tu.store(traits::NEXT_PC, PC_val_v);
-        tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP), 2));
         }
         else{
         	this->gen_raise_trap(tu, 0, 2);
@@ -3500,6 +3516,7 @@ private:
         gen_set_pc(tu, pc, traits::NEXT_PC);
         tu.open_scope();
         this->gen_set_tval(tu, instr);
+        tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(NO_JUMP),32));
         if(rs1>=static_cast<uint32_t>(traits:: RFS)) {
             this->gen_raise_trap(tu, 0, static_cast<int32_t>(traits:: RV_CAUSE_ILLEGAL_INSTRUCTION));
         }
@@ -3512,7 +3529,7 @@ private:
         	   new_pc,
         	   tu.constant(addr_mask,32)),32);
         	tu.store(traits::NEXT_PC, PC_val_v);
-        	tu.store(traits::LAST_BRANCH, tu.constant(2U, 2));
+        	tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP), 2));
         }
         auto returnValue = std::make_tuple(BRANCH);
         
@@ -3724,13 +3741,12 @@ vm_impl<ARCH>::gen_single_inst_behavior(virt_addr_t &pc, unsigned int &inst_cnt,
 
 template <typename ARCH> void vm_impl<ARCH>::gen_raise_trap(tu_builder& tu, uint16_t trap_id, uint16_t cause) {
     tu("  *trap_state = {:#x};", 0x80 << 24 | (cause << 16) | trap_id);
-    tu.store(traits::NEXT_PC, tu.constant(std::numeric_limits<uint32_t>::max(), 32));
 }
 
 template <typename ARCH> void vm_impl<ARCH>::gen_leave_trap(tu_builder& tu, unsigned lvl) {
     tu("leave_trap(core_ptr, {});", lvl);
     tu.store(traits::NEXT_PC, tu.read_mem(traits::CSR, (lvl << 8) + 0x41, traits::XLEN));
-    tu.store(traits::LAST_BRANCH, tu.constant(std::numeric_limits<uint32_t>::max(), 32));
+    tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP), 32));
 }
 
 template <typename ARCH> void vm_impl<ARCH>::gen_wait(tu_builder& tu, unsigned type) {
@@ -3747,7 +3763,7 @@ template <typename ARCH> void vm_impl<ARCH>::gen_trap_behavior(tu_builder& tu) {
     tu("trap_entry:");
     this->gen_sync(tu, POST_SYNC, -1);    
     tu("enter_trap(core_ptr, *trap_state, *pc, tval);");
-    tu.store(traits::LAST_BRANCH, tu.constant(std::numeric_limits<uint32_t>::max(),32));
+    tu.store(traits::LAST_BRANCH, tu.constant(static_cast<int>(UNKNOWN_JUMP),32));
     tu("return *next_pc;");
 }