//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="L4.IntrinsicKernel"
// Project: StgSharp
// AuthorGroup: Nitload
// Copyright (c) Nitload. All rights reserved.
//     
// 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.
//     
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.HighPerformance.Memory
{
    public unsafe partial class L4
    {

        private interface IIntrinsicKernel
        {

            static IIntrinsicKernel Instance { get; } = Create();

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public void AgeAll(
                        EvictionArray* eviction
            );

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public int ScanEvict(
                       byte* vPtr,
                       Vector128<byte> three
            );

            private static IIntrinsicKernel Create()
            {
                if (Sse42.IsSupported)
                {
                    return new SseKernel();
                } else
                {
                    throw new PlatformNotSupportedException("No supported intrinsic kernel found for current platform.");
                }
            }

        }

        private struct SseKernel : IIntrinsicKernel
        {

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public void AgeAll(
                        EvictionArray* eviction
            )
            {
                Vector128<byte> one = Vector128.Create((byte)0x01);
                Vector128<byte> max = Vector128.Create((byte)0x03);
                byte* p = (byte*)eviction;
                for (int i = 0; i < CacheLineCount; i += 16)
                {
                    Vector128<byte> v = Sse2.LoadVector128(p + i);
                    v = Sse2.AddSaturate(v, one);
                    v = Sse2.Min(v, max);
                    Sse2.Store(p + i, v);
                }
            }

            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public int ScanEvict(
                       byte* vPtr,
                       Vector128<byte> three
            )
            {
                Vector128<byte> v = Sse2.LoadVector128(vPtr);
                Vector128<byte> mask = Sse2.CompareEqual(v, three);
                return Sse2.MoveMask(mask);
            }

        }

    }
}