Make CpuFloorKernel kernel stateless

- Rename NEFloorKernel to CpuFloorKernel to accomodate new ISA
implementations
- Remove state and instead pass tensors to operate during run
- Add member function to generate an execution window given an input and
output tensor description

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I9240b8ec534589c0f15c354f771f1ac5d7010c3b
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4773
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>
diff --git a/src/core/cpu/kernels/floor/CpuFloorKernel.cpp b/src/core/cpu/kernels/floor/CpuFloorKernel.cpp
new file mode 100644
index 0000000..738f04d
--- /dev/null
+++ b/src/core/cpu/kernels/floor/CpuFloorKernel.cpp
@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2017-2021 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 "src/core/cpu/kernels/CpuFloorKernel.h"
+
+#include "arm_compute/core/Coordinates.h"
+#include "arm_compute/core/Helpers.h"
+#include "arm_compute/core/ITensor.h"
+#include "arm_compute/core/Validate.h"
+#include "src/core/CPP/Validate.h"
+#include "src/core/helpers/AutoConfiguration.h"
+#include "src/core/helpers/WindowHelpers.h"
+
+#include "src/core/common/Registrars.h"
+#include "src/core/cpu/kernels/floor/impl/list.h"
+
+namespace arm_compute
+{
+namespace cpu
+{
+namespace kernels
+{
+namespace
+{
+struct FloorSelectorData
+{
+    DataType dt;
+};
+
+using FloorSelectorPtr = std::add_pointer<bool(const FloorSelectorData &data)>::type;
+using FloorUKernelPtr  = std::add_pointer<void(const void *, void *, int)>::type;
+
+struct FloorUKernel
+{
+    const char            *name;
+    const FloorSelectorPtr is_selected;
+    FloorUKernelPtr        func;
+};
+
+static const FloorUKernel available_kernels[] =
+{
+    {
+        "fp16_neon_floor",
+        [](const FloorSelectorData & data) { return data.dt == DataType::F16; },
+        REGISTER_FP16_NEON(arm_compute::cpu::fp16_neon_floor)
+    },
+    {
+        "f32_neon_floor",
+        [](const FloorSelectorData & data) { return data.dt == DataType::F32; },
+        REGISTER_FP32_NEON(arm_compute::cpu::fp32_neon_floor)
+    },
+};
+
+/** Micro-kernel selector
+ *
+ * @param[in] data Selection data passed to help pick the appropriate micro-kernel
+ *
+ * @return A matching micro-kernel else nullptr
+ */
+const FloorUKernel *get_implementation(const FloorSelectorData &data)
+{
+    for(const auto &uk : available_kernels)
+    {
+        if(uk.is_selected(data))
+        {
+            return &uk;
+        }
+    }
+    return nullptr;
+}
+
+Status validate_arguments(const ITensorInfo *src, const ITensorInfo *dst)
+{
+    ARM_COMPUTE_RETURN_ERROR_ON_NULLPTR(src, dst);
+
+    const auto *uk = get_implementation(FloorSelectorData{ src->data_type() });
+    ARM_COMPUTE_RETURN_ERROR_ON(uk == nullptr || uk->func == nullptr);
+
+    // Validate in case of configured output
+    if(dst->total_size() > 0)
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_TYPES(src, dst);
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_SHAPES(src, dst);
+    }
+
+    return Status{};
+}
+} // namespace
+
+void CpuFloorKernel::configure(const ITensorInfo *src, ITensorInfo *dst)
+{
+    ARM_COMPUTE_ERROR_ON_NULLPTR(src, dst);
+
+    // Auto initialize output
+    auto_init_if_empty(*dst, src->tensor_shape(), 1, src->data_type());
+
+    // Validate
+    ARM_COMPUTE_ERROR_THROW_ON(validate_arguments(src, dst));
+
+    // Configure kernel window
+    const Window win = calculate_max_window(*src, Steps());
+
+    Coordinates coord;
+    coord.set_num_dimensions(dst->num_dimensions());
+    dst->set_valid_region(ValidRegion(coord, dst->tensor_shape()));
+
+    ICPPKernel::configure(win);
+}
+
+Window CpuFloorKernel::infer_window(const ITensorInfo *src, const ITensorInfo *dst)
+{
+    ARM_COMPUTE_UNUSED(dst);
+    ARM_COMPUTE_ERROR_ON(!bool(validate_arguments(src, dst)));
+
+    Window win;
+    win.use_tensor_dimensions(src->tensor_shape());
+    return win;
+}
+
+Status CpuFloorKernel::validate(const ITensorInfo *input, const ITensorInfo *output)
+{
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_arguments(input, output));
+    return Status{};
+}
+
+void CpuFloorKernel::run_op(ITensorPack &tensors, const Window &window, const ThreadInfo &info)
+{
+    ARM_COMPUTE_UNUSED(info);
+    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
+    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(IKernel::window(), window);
+
+    ARM_COMPUTE_ERROR_ON(tensors.empty());
+
+    const ITensor *src = tensors.get_const_tensor(TensorType::ACL_SRC);
+    ITensor       *dst = tensors.get_tensor(TensorType::ACL_DST);
+
+    const auto  len     = static_cast<int>(window.x().end()) - static_cast<int>(window.x().start());
+    const auto *ukernel = get_implementation(FloorSelectorData{ src->info()->data_type() });
+
+    Window win{ window };
+    win.set(Window::DimX, Window::Dimension(0, 1, 1));
+
+    Iterator src_it(src, win);
+    Iterator dst_it(dst, win);
+
+    execute_window_loop(win, [&](const Coordinates &)
+    {
+        ukernel->func(src_it.ptr(), dst_it.ptr(), len);
+    },
+    src_it, dst_it);
+}
+
+const char *CpuFloorKernel::name() const
+{
+    return "CpuFloorKernel";
+}
+} // namespace kernels
+} // namespace cpu
+} // namespace arm_compute