1 files changed, 79 insertions, 0 deletions
diff --git a/src/core/helpers/LUTManager.cpp b/src/core/helpers/LUTManager.cpp
new file mode 100644
index 0000000000..06e35eed8c
--- /dev/null
+++ b/src/core/helpers/LUTManager.cpp
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2024 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/helpers/LUTManager.h"
+
+namespace arm_compute
+{
+#ifdef __aarch64__
+namespace
+{
+
+void init_lut_fp16(ActivationLayerInfo::LookupTable65536 *lut)
+{
+    union Element
+    {
+        uint16_t  i = 0;
+        float16_t fp;
+    } item;
+    // Fill lut by iterating over all 16 bit values using the union.
+    while (true)
+    {
+        (*lut)[item.i] = 1.f / (1.f + std::exp(-item.fp));
+        if (item.i == 65535)
+            break;
+        item.i++;
+    }
+}
+} // namespace
+
+std::shared_ptr<ActivationLayerInfo::LookupTable65536> LUTManager::get_lut_table(LUTInfo info)
+{
+    const auto itr   = map_fp16.find(info);
+    auto       s_ptr = (itr != map_fp16.end()) ? itr->second.lock() : nullptr; // nullptr if invalid or not found.
+    if (s_ptr != nullptr)
+    {
+        // Found and valid
+        return s_ptr; // Return weak ptr as shared ptr
+    }
+    else
+    {
+        // Not found, or pointer not valid
+        // We do not use make_shared to prevent the weak_ptr keeping the control block alive
+        std::shared_ptr<ActivationLayerInfo::LookupTable65536> ptr(new ActivationLayerInfo::LookupTable65536);
+        init_lut_fp16(ptr.get());
+        map_fp16[info] = ptr;
+        return ptr;
+    }
+}
+#endif // __aarch64__
+
+// Static function to get LutManager instance
+LUTManager &LUTManager::get_instance()
+{
+    static auto inst_ = std::make_unique<LUTManager>(); // The one, single instance.
+    return *inst_;
+}
+
+} // namespace arm_compute