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diff --git a/Drivers/CMSIS/NN/Source/ActivationFunctions/arm_nn_activations_q15.c b/Drivers/CMSIS/NN/Source/ActivationFunctions/arm_nn_activations_q15.c
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+/*
+ * Copyright (C) 2010-2020 Arm Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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
+ *
+ * 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.
+ */
+
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS NN Library
+ * Title:        arm_nn_activations_q15.c
+ * Description:  Q15 neural network activation function using direct table look-up
+ *
+ * $Date:        09. October 2020
+ * $Revision:    V.1.0.1
+ *
+ * Target Processor:  Cortex-M cores
+ *
+ * -------------------------------------------------------------------- */
+
+#include "arm_nn_tables.h"
+#include "arm_nnfunctions.h"
+
+/**
+ *  @ingroup groupNN
+ */
+
+/**
+ * @addtogroup Acti
+ * @{
+ */
+
+/**
+ * @brief neural network activation function using direct table look-up
+ *
+ * @note  Refer header file for details.
+ *
+ */
+
+void arm_nn_activations_direct_q15(q15_t *data, uint16_t size, uint16_t int_width, arm_nn_activation_type type)
+{
+    uint16_t i = size;
+    q15_t *pIn = data;
+    q15_t *pOut = data;
+    uint16_t shift_size = 8 + 3 - int_width;
+    uint32_t bit_mask = 0x7FF >> int_width;
+    uint32_t full_frac = bit_mask + 1;
+    const q15_t *lookup_table;
+
+    switch (type)
+    {
+    case ARM_SIGMOID:
+        lookup_table = sigmoidTable_q15;
+        break;
+    case ARM_TANH:
+    default:
+        lookup_table = tanhTable_q15;
+        break;
+    }
+
+    while (i)
+    {
+        q15_t out;
+        q15_t in = *pIn++;
+        q15_t frac = (uint32_t)in & bit_mask;
+        q15_t value = lookup_table[(uint8_t)(in >> shift_size)];
+        if ((in >> shift_size) != 0x7f)
+        {
+            q15_t value2 = lookup_table[(uint8_t)(1 + ((uint8_t)(in >> shift_size)))];
+            /* doing the interpolation here for better accuracy */
+            out = ((q31_t)(full_frac - frac) * value + (q31_t)value2 * frac) >> shift_size;
+        }
+        else
+        {
+            /* the largest positive value does not have a right side for linear interpolation */
+            out = value;
+        }
+
+        *pOut++ = out;
+        i--;
+    }
+}
+
+/**
+ * @} end of Acti group
+ */