diff --git a/Python/ceval.c b/Python/ceval.c
index 9110e80..0808a95 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -903,8 +903,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
     { \
         if (!lltrace && !_Py_TracingPossible) { \
             f->f_lasti = INSTR_OFFSET(); \
-            opcode = NEXTOP(); \
-            oparg = NEXTARG(); \
+            NEXTOPARG(); \
             goto *opcode_targets[opcode]; \
         } \
         goto fast_next_opcode; \
@@ -914,8 +913,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
     { \
         if (!_Py_TracingPossible) { \
             f->f_lasti = INSTR_OFFSET(); \
-            opcode = NEXTOP(); \
-            oparg = NEXTARG(); \
+            NEXTOPARG(); \
             goto *opcode_targets[opcode]; \
         } \
         goto fast_next_opcode; \
@@ -981,9 +979,15 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 
 /* Code access macros */
 
+#ifdef WORDS_BIGENDIAN
+    #define OPOF(word) ((word)>>8)
+    #define ARGOF(word) ((word)&255)
+#else
+    #define OPOF(word) ((word)&255)
+    #define ARGOF(word) ((word)>>8)
+#endif
 #define INSTR_OFFSET()  ((int)(next_instr - first_instr))
-#define NEXTOP()        (next_instr+=2, next_instr[-2])
-#define NEXTARG()       (next_instr[-1])
+#define NEXTOPARG()     (oparg = *(unsigned short*)next_instr, opcode = OPOF(oparg), oparg = ARGOF(oparg), next_instr += 2)
 #define PEEKARG()       (next_instr[1])
 #define JUMPTO(x)       (next_instr = first_instr + (x))
 #define JUMPBY(x)       (next_instr += (x))
@@ -1021,9 +1025,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 #define PREDICT(op) \
     do{ \
         if (*next_instr == op){ \
-            opcode = op; \
-            oparg = PEEKARG(); \
-            next_instr += 2; \
+            NEXTOPARG(); \
             goto PRED_##op; \
         } \
     } while(0)
@@ -1313,8 +1315,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 
         /* Extract opcode and argument */
 
-        opcode = NEXTOP();
-        oparg = NEXTARG();
+        NEXTOPARG();
     dispatch_opcode:
 #ifdef DYNAMIC_EXECUTION_PROFILE
 #ifdef DXPAIRS
@@ -3432,8 +3433,9 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
         }
 
         TARGET(EXTENDED_ARG) {
-            opcode = NEXTOP();
-            oparg = oparg<<8 | NEXTARG();
+            int oldoparg = oparg;
+            NEXTOPARG();
+            oparg |= oldoparg << 8;
             goto dispatch_opcode;
         }
 
@@ -5298,10 +5300,11 @@ unicode_concatenate(PyObject *v, PyObject *w,
          * 'variable'.  We try to delete the variable now to reduce
          * the refcnt to 1.
          */
-        switch (*next_instr) {
+        int opcode, oparg;
+        NEXTOPARG();
+        switch (opcode) {
         case STORE_FAST:
         {
-            int oparg = PEEKARG();
             PyObject **fastlocals = f->f_localsplus;
             if (GETLOCAL(oparg) == v)
                 SETLOCAL(oparg, NULL);
@@ -5311,7 +5314,7 @@ unicode_concatenate(PyObject *v, PyObject *w,
         {
             PyObject **freevars = (f->f_localsplus +
                                    f->f_code->co_nlocals);
-            PyObject *c = freevars[PEEKARG()];
+            PyObject *c = freevars[oparg];
             if (PyCell_GET(c) == v)
                 PyCell_Set(c, NULL);
             break;
@@ -5319,7 +5322,7 @@ unicode_concatenate(PyObject *v, PyObject *w,
         case STORE_NAME:
         {
             PyObject *names = f->f_code->co_names;
-            PyObject *name = GETITEM(names, PEEKARG());
+            PyObject *name = GETITEM(names, oparg);
             PyObject *locals = f->f_locals;
             if (PyDict_CheckExact(locals) &&
                 PyDict_GetItem(locals, name) == v) {