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, 141 insertions, 0 deletions

diff --git a/src/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.cpp b/src/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.cpp
new file mode 100644
index 0000000000..aa3c280788
--- /dev/null
+++ b/src/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.cpp
@@ -0,0 +1,141 @@
+/*
+ * 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.
+ */
+#include "arm_compute/core/NEON/kernels/NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel.h"
+
+#include "arm_compute/core/Error.h"
+#include "arm_compute/core/Helpers.h"
+#include "arm_compute/core/ITensor.h"
+#include "arm_compute/core/Types.h"
+#include "arm_compute/core/Validate.h"
+#include "arm_compute/core/Window.h"
+
+#include <arm_neon.h>
+#include <cstddef>
+#include <cstdint>
+
+using namespace arm_compute;
+
+namespace arm_compute
+{
+class Coordinates;
+} // namespace arm_compute
+
+NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel::NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel()
+    : _input(nullptr), _output(nullptr), _result_offset(0), _result_mult_int(0), _result_shift(0)
+{
+}
+
+void NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel::configure(const ITensor *input, ITensor *output, int result_offset, int result_mult_int, int result_shift)
+{
+    ARM_COMPUTE_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input, 1, DataType::S32);
+    ARM_COMPUTE_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(output, 1, DataType::QASYMM8);
+
+    _input           = input;
+    _output          = output;
+    _result_offset   = result_offset;
+    _result_mult_int = result_mult_int;
+    _result_shift    = result_shift;
+
+    constexpr unsigned int num_elems_processed_per_iteration = 16;
+
+    // Configure kernel window
+    Window win = calculate_max_window(*output->info(), Steps(num_elems_processed_per_iteration));
+
+    AccessWindowHorizontal input_access(input->info(), 0, num_elems_processed_per_iteration);
+    AccessWindowHorizontal output_result_access(output->info(), 0, num_elems_processed_per_iteration);
+
+    update_window_and_padding(win,
+                              input_access,
+                              output_result_access);
+
+    output_result_access.set_valid_region(win, ValidRegion(Coordinates(0, 0), output->info()->tensor_shape()));
+
+    INEKernel::configure(win);
+}
+
+void NEGEMMLowpQuantizeDownInt32ToUint8ScaleKernel::run(const Window &window, const ThreadInfo &info)
+{
+    ARM_COMPUTE_UNUSED(info);
+    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
+    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(INEKernel::window(), window);
+
+    const int32x4_t result_offset_s32 = vdupq_n_s32(_result_offset);
+    const int32x4_t result_shift_s32  = vdupq_n_s32(-_result_shift);
+    const int32x4_t zero_s32          = vdupq_n_s32(0);
+
+    Iterator in(_input, window);
+    Iterator out(_output, window);
+
+    execute_window_loop(window, [&](const Coordinates & id)
+    {
+        int32x4x4_t in_s32 =
+        {
+            {
+                vld1q_s32(reinterpret_cast<const int32_t *>(in.ptr()) + 0),
+                vld1q_s32(reinterpret_cast<const int32_t *>(in.ptr()) + 4),
+                vld1q_s32(reinterpret_cast<const int32_t *>(in.ptr()) + 8),
+                vld1q_s32(reinterpret_cast<const int32_t *>(in.ptr()) + 12)
+            }
+        };
+
+        // Add the offset terms to GEMM's result
+        in_s32.val[0] = vaddq_s32(in_s32.val[0], result_offset_s32);
+        in_s32.val[1] = vaddq_s32(in_s32.val[1], result_offset_s32);
+        in_s32.val[2] = vaddq_s32(in_s32.val[2], result_offset_s32);
+        in_s32.val[3] = vaddq_s32(in_s32.val[3], result_offset_s32);
+
+        // Multiply by c_mult_int
+        in_s32.val[0] = vmulq_n_s32(in_s32.val[0], _result_mult_int);
+        in_s32.val[1] = vmulq_n_s32(in_s32.val[1], _result_mult_int);
+        in_s32.val[2] = vmulq_n_s32(in_s32.val[2], _result_mult_int);
+        in_s32.val[3] = vmulq_n_s32(in_s32.val[3], _result_mult_int);
+
+        // Shift final result (negative value shift right)
+        in_s32.val[0] = vshlq_s32(in_s32.val[0], result_shift_s32);
+        in_s32.val[1] = vshlq_s32(in_s32.val[1], result_shift_s32);
+        in_s32.val[2] = vshlq_s32(in_s32.val[2], result_shift_s32);
+        in_s32.val[3] = vshlq_s32(in_s32.val[3], result_shift_s32);
+
+        // Saturate negative values
+        in_s32.val[0] = vmaxq_s32(in_s32.val[0], zero_s32);
+        in_s32.val[1] = vmaxq_s32(in_s32.val[1], zero_s32);
+        in_s32.val[2] = vmaxq_s32(in_s32.val[2], zero_s32);
+        in_s32.val[3] = vmaxq_s32(in_s32.val[3], zero_s32);
+
+        // Convert S32 to S16
+        const int16x8x2_t in_s16 =
+        {
+            {
+                vcombine_s16(vqmovn_s32(in_s32.val[0]), vqmovn_s32(in_s32.val[1])),
+                vcombine_s16(vqmovn_s32(in_s32.val[2]), vqmovn_s32(in_s32.val[3]))
+            }
+        };
+
+        // Convert S16 to U8
+        const uint8x16_t out_u8 = vcombine_u8(vqmovun_s16(in_s16.val[0]), vqmovun_s16(in_s16.val[1]));
+
+        vst1q_u8(out.ptr(), out_u8);
+    },
+    in, out);
+}
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