diff --git a/gen_input/templates/interp/CORENAME.cpp.gtl b/gen_input/templates/interp/CORENAME.cpp.gtl
index aaedc43..1c45797 100644
--- a/gen_input/templates/interp/CORENAME.cpp.gtl
+++ b/gen_input/templates/interp/CORENAME.cpp.gtl
@@ -267,7 +267,7 @@ typename vm_base<ARCH>::virt_addr_t vm_impl<ARCH>::execute_inst(finish_cond_e co
             uint32_t inst_index = instr_decoder.decode_instr(instr);
             opcode_e inst_id = arch::traits<ARCH>::opcode_e::MAX_OPCODE;;
             if(inst_index <instr_descr.size())
-                inst_id = instr_descr.at(instr_decoder.decode_instr(instr)).op;
+                inst_id = instr_descr[inst_index].op;
 
             // pre execution stuff
             this->core.reg.last_branch = 0;