COMPMID-439: Implement NEON Quantization Layer.

Change-Id: Iefbb421915e56d880d6a3e20c113913560f6ca10
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/79934
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>

1 files changed, 106 insertions, 0 deletions

diff --git a/src/core/NEON/kernels/NEQuantizationLayerKernel.cpp b/src/core/NEON/kernels/NEQuantizationLayerKernel.cpp
new file mode 100644
index 0000000000..fbf7e1ba87
--- /dev/null
+++ b/src/core/NEON/kernels/NEQuantizationLayerKernel.cpp
@@ -0,0 +1,106 @@
+/*
+ * 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/NEQuantizationLayerKernel.h"
+
+#include "arm_compute/core/Error.h"
+#include "arm_compute/core/Helpers.h"
+#include "arm_compute/core/TensorInfo.h"
+#include "arm_compute/core/Utils.h"
+#include "arm_compute/core/Validate.h"
+#include "arm_compute/core/Window.h"
+
+#include <arm_neon.h>
+
+using namespace arm_compute;
+
+NEQuantizationLayerKernel::NEQuantizationLayerKernel()
+    : _input(nullptr), _output(nullptr), _min(nullptr), _max(nullptr)
+{
+}
+
+void NEQuantizationLayerKernel::configure(const ITensor *input, ITensor *output, const float *min, const float *max)
+{
+    ARM_COMPUTE_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input, 1, DataType::F32);
+    ARM_COMPUTE_ERROR_ON_NULLPTR(output);
+
+    // Output tensor auto initialization if not yet initialized
+    auto_init_if_empty(*output->info(), input->info()->tensor_shape(), 1, DataType::U8, 0);
+
+    ARM_COMPUTE_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(output, 1, DataType::U8);
+    ARM_COMPUTE_ERROR_ON_MISMATCHING_SHAPES(input, output);
+
+    _input  = input;
+    _output = output;
+    _min    = min;
+    _max    = max;
+
+    constexpr unsigned int num_elems_processed_per_iteration = 8;
+
+    // Configure window
+    Window                 win = calculate_max_window(*input->info(), Steps(num_elems_processed_per_iteration));
+    AccessWindowHorizontal output_access(output->info(), 0, num_elems_processed_per_iteration);
+    update_window_and_padding(win, AccessWindowHorizontal(input->info(), 0, num_elems_processed_per_iteration), output_access);
+    output_access.set_valid_region(win, input->info()->valid_region());
+
+    INEKernel::configure(win);
+}
+
+void NEQuantizationLayerKernel::run(const Window &window)
+{
+    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
+    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(INEKernel::window(), window);
+
+    Iterator input(_input, window);
+    Iterator output(_output, window);
+
+    const float32x4_t vmin             = vdupq_n_f32(*_min);
+    const float32x4_t inv_range        = vdupq_n_f32(1.0f / (*_max - *_min));
+    const float32x4_t quantization_max = vdupq_n_f32(255.0f);
+    const float32x4_t quantization_mul = vdupq_n_f32(256.0f);
+
+    // Uniformly map values to range 8bit integers, i.e. [min, max] -> [0, 255]
+    execute_window_loop(window, [&](const Coordinates & id)
+    {
+        float32x4x2_t val = vld2q_f32(reinterpret_cast<const float *>(input.ptr()));
+        // Map float values to range [0.0, 1.0]
+        val.val[0] = vsubq_f32(val.val[0], vmin);
+        val.val[1] = vsubq_f32(val.val[1], vmin);
+        val.val[0] = vmulq_f32(val.val[0], inv_range);
+        val.val[1] = vmulq_f32(val.val[1], inv_range);
+
+        // Quantize
+        val.val[0] = vmulq_f32(val.val[0], quantization_mul);
+        val.val[1] = vmulq_f32(val.val[1], quantization_mul);
+        val.val[0] = vminq_f32(val.val[0], quantization_max);
+        val.val[1] = vminq_f32(val.val[1], quantization_max);
+
+        const uint32x4_t   val_u32_low  = vcvtq_u32_f32(val.val[0]);
+        const uint32x4_t   val_u32_high = vcvtq_u32_f32(val.val[1]);
+        const uint16x4x2_t val_u16      = vzip_u16(vmovn_u32(val_u32_low), vmovn_u32(val_u32_high));
+
+        const uint8x8_t quantized = vmovn_u16(vcombine_u16(val_u16.val[0], val_u16.val[1]));
+        vst1_u8(reinterpret_cast<uint8_t *>(output.ptr()), quantized);
+    },
+    input, output);
+}