Make CpuActivation stateless

- Rename NEActivationLayer to CpuActivation
- Add member function to generate execution window

Partially Resolves: COMPMID-3992

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I4e1ae15cf456b860d3080b2fedc4dbcce7d1bb79
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4791
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michalis Spyrou <michalis.spyrou@arm.com>

1 files changed, 139 insertions, 0 deletions

diff --git a/src/core/cpu/kernels/activation/NEON/qsymm16.cpp b/src/core/cpu/kernels/activation/NEON/qsymm16.cpp
new file mode 100644
index 0000000000..9eee360427
--- /dev/null
+++ b/src/core/cpu/kernels/activation/NEON/qsymm16.cpp
@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2020-2021 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 "arm_compute/core/Helpers.h"
+#include "arm_compute/core/ITensorPack.h"
+#include "arm_compute/core/Window.h"
+#include "arm_compute/core/experimental/Types.h"
+#include "src/core/NEON/NEMath.h"
+#include "src/core/NEON/NESymm.h"
+#include "src/core/NEON/wrapper/wrapper.h"
+#include "src/core/common/Validate.h"
+
+#include <arm_neon.h>
+#include <cmath>
+#include <cstddef>
+
+namespace arm_compute
+{
+namespace cpu
+{
+void qsymm16_neon_activation(const ITensor *src, ITensor *dst, const ActivationLayerInfo &act_info, const Window &window)
+{
+    constexpr int                                 window_step_x  = 8;
+    const auto                                    window_start_x = static_cast<int>(window.x().start());
+    const auto                                    window_end_x   = static_cast<int>(window.x().end());
+    const ActivationLayerInfo::ActivationFunction act            = act_info.activation();
+
+    Window win_collapsed = window.collapse_if_possible(window, Window::DimZ);
+    win_collapsed.set(Window::DimX, Window::Dimension(0, 1, 1));
+
+    Iterator input(src, win_collapsed);
+    Iterator output(dst, win_collapsed);
+
+    const UniformQuantizationInfo qi_in    = src->info()->quantization_info().uniform();
+    const UniformQuantizationInfo qi_out   = dst->info()->quantization_info().uniform();
+    const auto                    vconst_1 = vdupq_n_f32(1.f);
+    const float32x4_t             va_f32   = vdupq_n_f32(act_info.a());
+    const float32x4_t             vb_f32   = vdupq_n_f32(act_info.b());
+    const float                   a_f32    = act_info.a();
+    const float                   b_f32    = act_info.b();
+
+    execute_window_loop(win_collapsed, [&](const Coordinates &)
+    {
+        const auto input_ptr  = reinterpret_cast<const qsymm16_t *>(input.ptr());
+        const auto output_ptr = reinterpret_cast<qsymm16_t *>(output.ptr());
+
+        wrapper::traits::neon_bitvector_t<qsymm16_t, wrapper::traits::BitWidth::W128> tmp;
+        ARM_COMPUTE_UNUSED(tmp);
+
+        // Compute S elements per iteration
+        int x = window_start_x;
+        for(; x <= (window_end_x - window_step_x); x += window_step_x)
+        {
+            const auto vin = wrapper::vloadq(input_ptr + x);
+            if(act == ActivationLayerInfo::ActivationFunction::LOGISTIC)
+            {
+                // De-quantize
+                const auto vin_deq = vdequantize_int16(vin, qi_in.scale);
+                // Perform activation
+                const float32x4x2_t tmp_dep =
+                {
+                    {
+                        wrapper::vdiv(vconst_1, wrapper::vadd(vconst_1, wrapper::vexpq(wrapper::vneg(vin_deq.val[0])))),
+                        wrapper::vdiv(vconst_1, wrapper::vadd(vconst_1, wrapper::vexpq(wrapper::vneg(vin_deq.val[1])))),
+                    }
+                };
+                // Re-quantize to new output space
+                tmp = vquantize_int16(tmp_dep, qi_out.scale);
+            }
+            else if(act == ActivationLayerInfo::ActivationFunction::TANH)
+            {
+                // De-quantize
+                const auto vin_deq = vdequantize_int16(vin, qi_in.scale);
+                // Perform activation
+                const float32x4x2_t tmp_dep =
+                {
+                    {
+                        wrapper::vmul(va_f32, wrapper::vtanh(wrapper::vmul(vin_deq.val[0], vb_f32))),
+                        wrapper::vmul(va_f32, wrapper::vtanh(wrapper::vmul(vin_deq.val[1], vb_f32))),
+                    }
+                };
+                // Re-quantize to new output space
+                tmp = vquantize_int16(tmp_dep, qi_out.scale);
+            }
+            else
+            {
+                ARM_COMPUTE_ERROR("Unsupported activation function");
+            }
+            wrapper::vstore(output_ptr + x, tmp);
+        }
+
+        // Compute left-over elements
+        for(; x < window_end_x; ++x)
+        {
+            qsymm16_t in  = *(reinterpret_cast<const qsymm16_t *>(input_ptr + x));
+            qsymm16_t tmp = 0;
+            if(act == ActivationLayerInfo::ActivationFunction::LOGISTIC)
+            {
+                float tmp_f = dequantize_qsymm16(in, qi_in.scale);
+                tmp_f       = 1.f / (1.f + std::exp(-tmp_f));
+                tmp         = quantize_qsymm16(tmp_f, qi_out);
+            }
+            else if(act == ActivationLayerInfo::ActivationFunction::TANH)
+            {
+                float tmp_f = dequantize_qsymm16(in, qi_in.scale);
+                tmp_f       = a_f32 * std::tanh(b_f32 * tmp_f);
+                tmp         = quantize_qsymm16(tmp_f, qi_out);
+            }
+            else
+            {
+                ARM_COMPUTE_ERROR("Unsupported activation function");
+            }
+            *(output_ptr + x) = tmp;
+        }
+    },
+    input, output);
+}
+} // namespace cpu
+} // namespace arm_compute