Move CPU/GPU files from Core/Runtime to the respective backend folders

Legacy structure contained two libraries core/runtime with two backends
in each.
We reduce the core/runtime libraries to a single library thus merging
the backend files

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I69545765fe7a730368105cdbd067d3135ec7a174
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/6155
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/cpu/kernels/CpuMulKernel.h b/src/cpu/kernels/CpuMulKernel.h
new file mode 100644
index 0000000..b65ec20
--- /dev/null
+++ b/src/cpu/kernels/CpuMulKernel.h
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2016-2021 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.
+ */
+#ifndef ARM_COMPUTE_CPU_MUL_KERNEL_H
+#define ARM_COMPUTE_CPU_MUL_KERNEL_H
+
+#include "src/core/common/Macros.h"
+#include "src/cpu/ICpuKernel.h"
+
+namespace arm_compute
+{
+namespace cpu
+{
+namespace kernels
+{
+/** Interface for the kernel to perform multiplication between two tensors */
+class CpuMulKernel : public ICpuKernel
+{
+public:
+    CpuMulKernel() = default;
+    ARM_COMPUTE_DISALLOW_COPY_ALLOW_MOVE(CpuMulKernel);
+    /** Initialise the kernel's input, dst and border mode.
+     *
+     * Valid configurations (Src1,Src2) -> Dst :
+     *
+     *                                                       Support: Broadcast? Scale=1/255?
+     *   - (U8,U8)                         -> U8, S16                 N          Y
+     *   - (U8,S16)                        -> S16                     N          Y
+     *   - (S16,U8)                        -> S16                     N          Y
+     *   - (S16,S16)                       -> S16                     N          Y
+     *   - (S32,S32)                       -> S32                     Y          N
+     *   - (F16,F16)                       -> F16                     N          Y
+     *   - (F32,F32)                       -> F32                     Y          Y
+     *   - (QASYMM8,QASYMM8)               -> QASYMM8                 Y          Y
+     *   - (QASYMM8_SIGNED,QASYMM8_SIGNED) -> QASYMM8_SIGNED          Y          Y
+     *   - (QSYMM16,QSYMM16)               -> QSYMM16, S32            N          Y
+     *
+     * @note For @p scale equal to 1/255 only round to nearest even (implemented as round half up) is supported.
+     *       For all other scale values only round to zero (implemented as round towards minus infinity) is supported.
+     *
+     * @param[in]  src1            First input tensor. Data types supported: U8/QASYMM8/QASYMM8_SIGNED/S16/S32/QSYMM16/F16/F32
+     * @param[in]  src2            Second input tensor. Data types supported: U8/QASYMM8/QASYMM8_SIGNED/S16/S32/QSYMM16/F16/F32
+     * @param[out] dst             Dst tensor. Data types supported: U8/QASYMM8/QASYMM8_SIGNED/S16/S32/QSYMM16/F16/F32
+     * @param[in]  scale           Scale to apply after multiplication.
+     *                             Scale must be positive and its value must be either 1/255 or 1/2^n where n is between 0 and 15.
+     *                             If both @p src1, @p src2 and @p dst are of datatype S32, scale cannot be 1/255
+     * @param[in]  overflow_policy Overflow policy. ConvertPolicy cannot be WRAP if any of the inputs is of quantized datatype
+     * @param[in]  rounding_policy Rounding policy.
+     */
+    void configure(ITensorInfo *src1, ITensorInfo *src2, ITensorInfo *dst, float scale, ConvertPolicy overflow_policy, RoundingPolicy rounding_policy);
+    /** Static function to check if given info will lead to a valid configuration
+     *
+     * Similar to @ref CpuMulKernel::configure()
+     *
+     * @return a status
+     */
+    static Status validate(const ITensorInfo *src1, const ITensorInfo *src2, const ITensorInfo *dst, float scale, ConvertPolicy overflow_policy, RoundingPolicy rounding_policy);
+
+    // Inherited methods overridden
+    void run_op(ITensorPack &tensors, const Window &window, const ThreadInfo &info) override;
+    const char *name() const override;
+
+private:
+    /** Common signature for all the specialised multiplication functions with integer scaling factor
+     *
+     * @param[in]  src1   Src1 tensor object.
+     * @param[in]  src2   Src2 tensor object.
+     * @param[out] dst    Dst tensor object.
+     * @param[in]  window Region on which to execute the kernel
+     * @param[in]  scale  Integer scale factor.
+     */
+    using MulFunctionInt = void(const ITensor *src1, const ITensor *src2, ITensor *dst, const Window &window, int scale);
+    /** Common signature for all the specialised multiplication functions with float scaling factor
+     *
+     * @param[in]  src1   Src1 tensor object.
+     * @param[in]  src2   Src2 tensor object.
+     * @param[out] dst    Dst tensor object.
+     * @param[in]  window Region on which to execute the kernel
+     * @param[in]  scale  Float scale factor.
+     */
+    using MulFunctionFloat = void(const ITensor *src1, const ITensor *src2, ITensor *dst, const Window &window, float scale);
+    /** Common signature for all the specialised QASYMM8 multiplication functions with float scaling factor
+     *
+     * @param[in]  src1   Src1 tensor object.
+     * @param[in]  src2   Src2 tensor object.
+     * @param[out] dst    Dst tensor object.
+     * @param[in]  window Region on which to execute the kernel
+     * @param[in]  scale  Float scale factor.
+     *
+     */
+    using MulFunctionQuantized = void(const ITensor *src1, const ITensor *src2, ITensor *dst, const Window &window, float scale);
+
+    MulFunctionFloat     *_func_float{ nullptr };
+    MulFunctionInt       *_func_int{ nullptr };
+    MulFunctionQuantized *_func_quantized{ nullptr };
+    float                 _scale{ 0 };
+    int                   _scale_exponent{ 0 };
+};
+
+/** Interface for the complex pixelwise multiplication kernel. */
+class CpuComplexMulKernel : public ICpuKernel
+{
+public:
+    CpuComplexMulKernel() = default;
+    ARM_COMPUTE_DISALLOW_COPY_ALLOW_MOVE(CpuComplexMulKernel);
+    /** Initialise the kernel's src, dst and border mode.
+     *
+     * @param[in]  src1 An src tensor. Data types supported: F32. Number of channels supported: 2 (complex tensor).
+     * @param[in]  src2 An src tensor. Data types supported: same as @p src1. Number of channels supported: same as @p src1.
+     * @param[out] dst  The dst tensor, Data types supported: same as @p src1.  Number of channels supported: same as @p src1.
+     */
+    void configure(ITensorInfo *src1, ITensorInfo *src2, ITensorInfo *dst);
+    /** Static function to check if given info will lead to a valid configuration
+     *
+     * Similar to @ref CpuComplexMulKernel::configure()
+     *
+     * @return a status
+     */
+    static Status validate(const ITensorInfo *src1, const ITensorInfo *src2, const ITensorInfo *dst);
+
+    // Inherited methods overridden:
+    void run_op(ITensorPack &tensors, const Window &window, const ThreadInfo &info) override;
+    const char *name() const override;
+};
+} // namespace kernels
+} // namespace cpu
+} // namespace arm_compute
+#endif /* ARM_COMPUTE_CPU_MUL_KERNEL_H */