// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Intrinsics.X86;
using System.Runtime.Intrinsics;

namespace IntelHardwareIntrinsicTest
{
    class Program
    {
        const int Pass = 100;
        const int Fail = 0;

        static unsafe int Main(string[] args)
        {
            int testResult = Pass;

            if (Sse.IsSupported)
            {
                using (TestTable<float> floatTable = new TestTable<float>(new float[4] { 1, -5, 100, 0 }, new float[4]))
                {
                    var vf1 = Unsafe.Read<Vector128<float>>(floatTable.inArray1Ptr);
                    var vf2 = Sse.ReciprocalScalar(vf1);
                    Unsafe.Write(floatTable.outArrayPtr, vf2);

                    if (!floatTable.CheckResult((x, y, z) => {
                        var expected = 1 / y[0];
                        return ((Math.Abs(expected - z[0]) <= 0.0003662109375f) // |Relative Error| <= 1.5 * 2^-12
                             || (float.IsNaN(expected) && float.IsNaN(z[0]))
                             || (float.IsNegativeInfinity(expected) && float.IsNegativeInfinity(z[0]))
                             || (float.IsPositiveInfinity(expected) && float.IsPositiveInfinity(z[0])))
                            && (z[1] == x[1]) && (z[2] == x[2]) && (z[3] == x[3]);
                    }))
                    {
                        Console.WriteLine("SSE ReciprocalScalar failed on float:");
                        foreach (var item in floatTable.outArray)
                        {
                            Console.Write(item + ", ");
                        }
                        Console.WriteLine();
                        testResult = Fail;
                    }
                }

                using (TestTable<float> floatTable = new TestTable<float>(new float[4] { 1, -5, 100, 0 }, new float[4] { 22, -1, -50, 0 }, new float[4]))
                {
                    var vf1 = Unsafe.Read<Vector128<float>>(floatTable.inArray1Ptr);
                    var vf2 = Unsafe.Read<Vector128<float>>(floatTable.inArray2Ptr);
                    var vf3 = Sse.ReciprocalScalar(vf1, vf2);
                    Unsafe.Write(floatTable.outArrayPtr, vf3);

                    if (!floatTable.CheckResult((x, y, z) => {
                        var expected = 1 / y[0];
                        return ((Math.Abs(expected - z[0]) <= 0.0003662109375f) // |Relative Error| <= 1.5 * 2^-12
                             || (float.IsNaN(expected) && float.IsNaN(z[0]))
                             || (float.IsNegativeInfinity(expected) && float.IsNegativeInfinity(z[0]))
                             || (float.IsPositiveInfinity(expected) && float.IsPositiveInfinity(z[0])))
                            && (z[1] == x[1]) && (z[2] == x[2]) && (z[3] == x[3]);
                    }))
                    {
                        Console.WriteLine("SSE ReciprocalScalar failed on float:");
                        foreach (var item in floatTable.outArray)
                        {
                            Console.Write(item + ", ");
                        }
                        Console.WriteLine();
                        testResult = Fail;
                    }
                }
            }

            return testResult;
        }

        public unsafe struct TestTable<T> : IDisposable where T : struct
        {
            public T[] inArray1;
            public T[] inArray2;
            public T[] outArray;

            public void* inArray1Ptr => inHandle1.AddrOfPinnedObject().ToPointer();
            public void* inArray2Ptr => inHandle2.AddrOfPinnedObject().ToPointer();
            public void* outArrayPtr => outHandle.AddrOfPinnedObject().ToPointer();

            GCHandle inHandle1;
            GCHandle inHandle2;
            GCHandle outHandle;
            public TestTable(T[] a, T[] b) : this(a, a, b)
            {
            }
            public TestTable(T[] a, T[] b, T[] c)
            {
                this.inArray1 = a;
                this.inArray2 = b;
                this.outArray = c;

                inHandle1 = GCHandle.Alloc(inArray1, GCHandleType.Pinned);
                inHandle2 = GCHandle.Alloc(inArray2, GCHandleType.Pinned);
                outHandle = GCHandle.Alloc(outArray, GCHandleType.Pinned);
            }
            public bool CheckResult(Func<T[], T[], T[], bool> check)
            {
                return check(inArray1, inArray2, outArray);
            }

            public void Dispose()
            {
                inHandle1.Free();
                inHandle2.Free();
                outHandle.Free();
            }
        }
    }
}