diff --git a/include/pocketpy/frame.h b/include/pocketpy/frame.h
index 77b01bb2..94c4d0c8 100644
--- a/include/pocketpy/frame.h
+++ b/include/pocketpy/frame.h
@@ -94,12 +94,6 @@ struct Frame {
     Frame(PyVar* p0, const CodeObject_& co, PyVar _module)
             : _ip(-1), _next_ip(0), _sp_base(p0), co(co.get()), _module(_module), _callable(nullptr), _locals(co.get(), p0) {}
 
-    int next_bytecode() {
-        _ip = _next_ip++;
-        PK_DEBUG_ASSERT(_ip >= 0 && _ip < co->codes.size());
-        return _ip;
-    }
-
     PyVar* actual_sp_base() const { return _locals.a; }
 
     int stack_size(ValueStack* _s) const { return _s->_sp - actual_sp_base(); }
diff --git a/src/ceval.cpp b/src/ceval.cpp
index 4b60d010..cec5d521 100644
--- a/src/ceval.cpp
+++ b/src/ceval.cpp
@@ -113,11 +113,14 @@ PyVar VM::__run_top_frame(){
 
 __NEXT_FRAME:
     const CodeObject* co = frame->co;
+    // TODO: when jit is enabled, co_codes may not be const
     const Bytecode* co_codes = co->codes.data();
     Bytecode byte;
 
-__NEXT_STEP:;
-    byte = co_codes[frame->next_bytecode()];
+__NEXT_STEP:
+    frame->_ip = frame->_next_ip;
+    frame->_next_ip++;
+    byte = co_codes[frame->_ip];
     CEVAL_STEP_CALLBACK()
 
 #if PK_DEBUG_CEVAL_STEP