Extract reference for operator FLOOR_DIV to standalone header

Move the reference implementation to its own header so that micro
can use it without the unrelated depedencies of reference_ops.h.

PR step 2 for issue  #45657

tensorflow/lite/kernels/floor_div.cc

@@ -41,12 +41,6 @@ struct OpData {
   bool requires_broadcast;
 };
 
-template <typename T>
-T FloorDiv(T input1, T input2) {
-  return std::floor(std::divides<double>()(static_cast<double>(input1),
-                                           static_cast<double>(input2)));
-}
-
 void* Init(TfLiteContext* context, const char* buffer, size_t length) {
   auto* data = new OpData;
   data->requires_broadcast = false;
@@ -118,12 +112,13 @@ TfLiteStatus EvalImpl(TfLiteContext* context, bool requires_broadcast,
     reference_ops::BroadcastBinaryFunction4DSlow<T, T, T>(
         GetTensorShape(input1), GetTensorData<T>(input1),
         GetTensorShape(input2), denominator_data, GetTensorShape(output),
-        GetTensorData<T>(output), FloorDiv<T>);
+        GetTensorData<T>(output), reference_ops::FloorDiv<T>);
   } else {
     reference_ops::BinaryFunction<T, T, T>(
         GetTensorShape(input1), GetTensorData<T>(input1),
         GetTensorShape(input2), GetTensorData<T>(input2),
-        GetTensorShape(output), GetTensorData<T>(output), FloorDiv<T>);
+        GetTensorShape(output), GetTensorData<T>(output),
+        reference_ops::FloorDiv<T>);
   }
 
   return kTfLiteOk;

tensorflow/lite/kernels/internal/BUILD

@@ -466,6 +466,7 @@ cc_library(
         "reference/fill.h",
         "reference/floor.h",
         "reference/floor_mod.h",
+        "reference/floor_div.h",
         "reference/fully_connected.h",
         "reference/hard_swish.h",
         "reference/integer_ops/add.h",
@@ -573,6 +574,7 @@ cc_library(
         "reference/fill.h",
         "reference/floor.h",
         "reference/floor_mod.h",
+        "reference/floor_div.h",
         "reference/fully_connected.h",
         "reference/hard_swish.h",
         "reference/l2normalization.h",

tensorflow/lite/kernels/internal/reference/floor_div.h

@@ -0,0 +1,35 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#ifndef TENSORFLOW_LITE_KERNELS_INTERNAL_REFERENCE_FLOOR_DIV_H_
+#define TENSORFLOW_LITE_KERNELS_INTERNAL_REFERENCE_FLOOR_DIV_H_
+
+#include <cmath>
+#include <functional>
+
+#include "tensorflow/lite/kernels/internal/types.h"
+
+namespace tflite {
+namespace reference_ops {
+
+template <typename T>
+T FloorDiv(T input1, T input2) {
+  return std::floor(std::divides<double>()(static_cast<double>(input1),
+                                           static_cast<double>(input2)));
+}
+
+}  // namespace reference_ops
+}  // namespace tflite
+
+#endif  // TENSORFLOW_LITE_KERNELS_INTERNAL_REFERENCE_FLOOR_DIV_H_

tensorflow/lite/kernels/internal/reference/reference_ops.h

@@ -45,6 +45,7 @@ limitations under the License.
 #include "tensorflow/lite/kernels/internal/reference/fill.h"
 #include "tensorflow/lite/kernels/internal/reference/floor.h"
 #include "tensorflow/lite/kernels/internal/reference/floor_mod.h"
+#include "tensorflow/lite/kernels/internal/reference/floor_div.h"
 #include "tensorflow/lite/kernels/internal/reference/fully_connected.h"
 #include "tensorflow/lite/kernels/internal/reference/hard_swish.h"
 #include "tensorflow/lite/kernels/internal/reference/l2normalization.h"