1 files changed, 8 insertions, 1 deletions
diff --git a/py/modbuiltins.c b/py/modbuiltins.c
index f62afd8074..a0c68930d8 100644
--- a/py/modbuiltins.c
+++ b/py/modbuiltins.c
@@ -378,7 +378,14 @@ MP_DEFINE_CONST_FUN_OBJ_1(mp_builtin_ord_obj, mp_builtin_ord);
 STATIC mp_obj_t mp_builtin_pow(size_t n_args, const mp_obj_t *args) {
     switch (n_args) {
         case 2: return mp_binary_op(MP_BINARY_OP_POWER, args[0], args[1]);
-        default: return mp_binary_op(MP_BINARY_OP_MODULO, mp_binary_op(MP_BINARY_OP_POWER, args[0], args[1]), args[2]); // TODO optimise...
+        default:
+#if !MICROPY_PY_BUILTINS_POW3
+            mp_raise_msg(&mp_type_NotImplementedError, "3-arg pow() not supported");
+#elif MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_MPZ
+            return mp_binary_op(MP_BINARY_OP_MODULO, mp_binary_op(MP_BINARY_OP_POWER, args[0], args[1]), args[2]);
+#else
+            return mp_obj_int_pow3(args[0], args[1], args[2]);
+#endif
     }
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_pow_obj, 2, 3, mp_builtin_pow);