COMPMID-675 - Reworked NEGEMMLowp interface/function

The new interface makes NEGEMMLowp able to work with ASYMM8 data types.

Implemented 2 new functions:
- NEGEMMLowpMatrixMultiplyCore
- NEGEMMLowpOutputStage

These functions should make the integration in android NN doable

For more information about GEMMLowp:
https://github.com/google/gemmlowp/blob/master/doc/low-precision.md

Change-Id: Ie2c775f45234f68ca53dba644b3a912b997fd890
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/95504
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Pablo Tello <pablo.tello@arm.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h b/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h
new file mode 100644
index 0000000000..8557ef42e1
--- /dev/null
+++ b/arm_compute/runtime/NEON/functions/NEGEMMLowpOutputStage.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2017 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef __ARM_COMPUTE_NEGEMMLOWPOUTPUTSTAGE_H__
+#define __ARM_COMPUTE_NEGEMMLOWPOUTPUTSTAGE_H__
+
+#include "arm_compute/runtime/NEON/INESimpleFunction.h"
+
+/** This file contains all available output stages for GEMMLowp on NEON.
+ *
+ *  In gemmlowp, the "output stage" is the process that takes a final int32 accumulator value (the output of @ref NEGEMMLowpMatrixMultiplyCore),
+ *  and processes it to obtain the final ASYMM8 value.
+ *
+ *  More information about the GEMMLowp output stage can be found at https://github.com/google/gemmlowp/blob/master/doc/output.md
+ */
+
+namespace arm_compute
+{
+class ITensor;
+
+/** Basic function to execute NEGEMMLowpQuantizeDownInt32ToUint8Scale on NEON.
+ *
+ *  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
+ *
+ *  where rounding = (result_shift < 1) ? 0 : (1 << (result_shift - 1))
+ *
+ *  This function calls the following NEON kernels:
+ *
+ * -# @ref NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel
+ *
+*/
+class NEGEMMLowpQuantizeDownInt32ToUint8Scale : public INESimpleFunction
+{
+public:
+    /** Initialise the kernel's inputs, output
+    *
+    * @param[in]  input           Input tensor. It is the output of @ref NEGEMMLowpMatrixMultiplyCore function. Data type supported: S32
+    * @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
+    */
+    void configure(const ITensor *input, ITensor *output, int result_offset, int result_mult_int, int result_shift);
+};
+}
+#endif /*__ARM_COMPUTE_NEGEMMLOWPOUTPUTSTAGE_H__ */
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