COMPMID-665 - NEON: Add QASYMM8 in place Activation layer

- Added min and max arguments for QuantizeDownInt32ToUint8Scale in order
  to apply bounded relu

- Added support for int32_t biases

- Extended tests

Change-Id: I015dae17faa7284766b5435ca33bcf593c1b2b69
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/96512
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
diff --git a/arm_compute/core/NEON/kernels/NEGEMMLowpOffsetContributionKernel.h b/arm_compute/core/NEON/kernels/NEGEMMLowpOffsetContributionKernel.h
index 04b8433..8c1bae9 100644
--- a/arm_compute/core/NEON/kernels/NEGEMMLowpOffsetContributionKernel.h
+++ b/arm_compute/core/NEON/kernels/NEGEMMLowpOffsetContributionKernel.h
@@ -35,6 +35,13 @@
  * This kernel takes a final int32 accumulator value (the output of @NEGEMMLowpMatrixMultiplyKernel),
  * and adds to it the offset contribution of matrix A and matrix B in-place.
  *
+ * The final result is:
+ *
+ * mm_result[i][k] = mm_result[i][k] +
+ *                   (vector_sum_col[k] * a_offset) +
+ *                   (vector_sum_row[i] * b_offset) +
+ *                   (a_offset * b_offset * k)
+ *
  */
 class NEGEMMLowpOffsetContributionKernel : public INEKernel
 {
diff --git a/arm_compute/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.h b/arm_compute/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.h
index 65f1042..4ec0e9d 100644
--- a/arm_compute/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.h
+++ b/arm_compute/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.h
@@ -36,7 +36,10 @@
  * The following computations will be performed by the kernel:
  *
  *  -# Add offset terms to final result
- *  -# Multiply each entry of result and round to nearest integer
+ *  -# Multiply each entry of result by result_mult_int
+ *  -# Add bias to final result if bias tensor is not a nullptr
+ *  -# Shift the int32 accumulator by result_shift
+ *  -# Clamp the value between the specified min and max bounds
  *  -# Clamp the resulting int32 values to the [0..255] range and cast to QASYMM8.
  *
  */
@@ -56,22 +59,44 @@
     /** Initialise the kernel's input and output.
      *
     * @param[in]  input           Input tensor. Data type supported: S32
+    * @param[in]  bias            Biases tensor. Only shared biases supported and it can be a nullptr if the biases addition is not required.
+    *                             Biases are 1D tensor with dimensions [OFM]. Data type supported: Same as @p input.
     * @param[out] output          Output tensor. Data type supported: Data type supported: QASYMM8
     * @param[in]  result_offset   Offset to be added to each element of the input matrix
     * @param[in]  result_mult_int Value to be multiplied to each element of the input matrix when once the result_offset has been add
     * @param[in]  result_shift    Number of bits to shift right the result before converting back to QASYMM8
+    * @param[in]  min             (Optional) Min value used to saturate down the output result before converting back to QASYMM8
+    * @param[in]  max             (Optional) Max value used to saturate up the output result before converting back to QASYMM8,
+    *                             Along with @p min, this value can be used to implement "rectified linear unit" activation functions
      */
-    void configure(const ITensor *input, ITensor *output, int result_offset, int result_mult_int, int result_shift);
+    void configure(const ITensor *input, const ITensor *bias, ITensor *output, int result_offset, int result_mult_int, int result_shift, int min = 0, int max = 0);
 
     // Inherited methods overridden:
     void run(const Window &window, const ThreadInfo &info) override;
 
 private:
-    const ITensor *_input;
-    ITensor       *_output;
-    int32_t        _result_offset;
-    int32_t        _result_mult_int;
-    int32_t        _result_shift;
+    /** Template function to run the NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel
+     *
+     * @param[in] window Region on which to execute the kernel. (Must be a valid region of the window returned by window()).
+     */
+    template <bool is_bounded_relu>
+    void run(const Window &window);
+
+    /** Common signature for all the specialised NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel functions
+     *
+     * @param[in] window Region on which to execute the kernel.
+     */
+    using QuantizeDownFunctionPtr = void (NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel::*)(const Window &window);
+
+    QuantizeDownFunctionPtr _func;
+    const ITensor          *_input;
+    const ITensor          *_bias;
+    ITensor                *_output;
+    int                     _result_offset;
+    int                     _result_mult_int;
+    int                     _result_shift;
+    int                     _min;
+    int                     _max;
 };
 } // namespace arm_compute
 
diff --git a/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h b/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h
index 8557ef4..a3db23a 100644
--- a/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h
+++ b/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h
@@ -43,14 +43,18 @@
  *  NEGEMMLowpQuantizeDownInt32ToUint8Scale depends on 3 parameters: result_offset, result_mult_int, result_shift
  *  The final result is:
  *
- *  ((input[i][k] + result_offset) * result_mult_int + rounding) >> result_shift
+ *  ((input[i][k] + result_offset) * result_mult_int) >> result_shift
  *
- *  where rounding = (result_shift < 1) ? 0 : (1 << (result_shift - 1))
+ * In case the bias tensor is provided, the final result is:
+ *
+ *  ((input[i][k] + result_offset) * result_mult_int + bias[k]) >> result_shift
  *
  *  This function calls the following NEON kernels:
  *
  * -# @ref NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel
  *
+ * @note The function accepts also 2 optional input arguments (min and max) which can be used to implement "rectified linear unit" activation functions
+ *       before the result is shifted right by result_shift
 */
 class NEGEMMLowpQuantizeDownInt32ToUint8Scale : public INESimpleFunction
 {
@@ -58,12 +62,17 @@
     /** Initialise the kernel's inputs, output
     *
     * @param[in]  input           Input tensor. It is the output of @ref NEGEMMLowpMatrixMultiplyCore function. Data type supported: S32
+    * @param[in]  bias            Biases tensor. Only shared biases supported and it can be a nullptr if the addition of biases is not required.
+    *                             Biases are 1D tensor with dimensions [OFM]. Data type supported: Same as @p input.
     * @param[out] output          Output tensor. Data type supported: Data type supported: QASYMM8
     * @param[in]  result_offset   Offset to be added to each element of the input matrix
     * @param[in]  result_mult_int Value to be multiplied to each element of the input matrix when once the result_offset has been add
     * @param[in]  result_shift    Number of bits to shift right the result before converting back to QASYMM8
+    * @param[in]  min             (Optional) Min value used to saturate down the output result before converting back to QASYMM8
+    * @param[in]  max             (Optional) Max value used to saturate up the output result before converting back to QASYMM8,
+    *                             Along with @p min, this value can be used to implement "rectified linear unit" activation functions
     */
-    void configure(const ITensor *input, ITensor *output, int result_offset, int result_mult_int, int result_shift);
+    void configure(const ITensor *input, const ITensor *bias, ITensor *output, int result_offset, int result_mult_int, int result_shift, int min = 0, int max = 0);
 };
 }
 #endif /*__ARM_COMPUTE_NEGEMMLOWPOUTPUTSTAGE_H__ */
\ No newline at end of file