using System; using System.Runtime.CompilerServices; using System.Runtime.InteropServices; namespace ARMeilleure.State { /// <summary> /// Represents a 128-bit vector. /// </summary> [StructLayout(LayoutKind.Sequential, Size = 16)] public struct V128 : IEquatable<V128> { // _e0 & _e1 could be marked as readonly, however they are not readonly because we modify them through the Unsafe // APIs. This also means that one should be careful when changing the layout of this struct. private ulong _e0; private ulong _e1; /// <summary> /// Gets a new <see cref="V128"/> with all bits set to zero. /// </summary> public static V128 Zero => new V128(0, 0); /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="double"/> value /// as a scalar. /// </summary> /// <param name="value">Scalar value</param> public V128(double value) : this(value, 0) { } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="double"/> elements. /// </summary> /// <param name="e0">Element 0</param> /// <param name="e1">Element 1</param> public V128(double e0, double e1) { _e0 = (ulong)BitConverter.DoubleToInt64Bits(e0); _e1 = (ulong)BitConverter.DoubleToInt64Bits(e1); } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="float"/> value as a /// scalar. /// </summary> /// <param name="value">Scalar value</param> public V128(float value) : this(value, 0, 0, 0) { } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="float"/> elements. /// </summary> /// <param name="e0">Element 0</param> /// <param name="e1">Element 1</param> /// <param name="e2">Element 2</param> /// <param name="e3">Element 3</param> public V128(float e0, float e1, float e2, float e3) { _e0 = (ulong)(uint)BitConverter.SingleToInt32Bits(e0) << 0; _e0 |= (ulong)(uint)BitConverter.SingleToInt32Bits(e1) << 32; _e1 = (ulong)(uint)BitConverter.SingleToInt32Bits(e2) << 0; _e1 |= (ulong)(uint)BitConverter.SingleToInt32Bits(e3) << 32; } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="ulong"/> /// elements. /// </summary> /// <param name="e0">Element 0</param> /// <param name="e1">Element 1</param> public V128(long e0, long e1) : this((ulong)e0, (ulong)e1) { } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="long"/> elements. /// </summary> /// <param name="e0">Element 0</param> /// <param name="e1">Element 1</param> public V128(ulong e0, ulong e1) { _e0 = e0; _e1 = e1; } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="int"/> elements. /// </summary> /// <param name="e0">Element 0</param> /// <param name="e1">Element 1</param> /// <param name="e2">Element 2</param> /// <param name="e3">Element 3</param> public V128(int e0, int e1, int e2, int e3) : this((uint)e0, (uint)e1, (uint)e2, (uint)e3) { } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct with the specified <see cref="uint"/> elements. /// </summary> /// <param name="e0">Element 0</param> /// <param name="e1">Element 1</param> /// <param name="e2">Element 2</param> /// <param name="e3">Element 3</param> public V128(uint e0, uint e1, uint e2, uint e3) { _e0 = (ulong)e0 << 0; _e0 |= (ulong)e1 << 32; _e1 = (ulong)e2 << 0; _e1 |= (ulong)e3 << 32; } /// <summary> /// Initializes a new instance of the <see cref="V128"/> struct from the specified <see cref="byte"/> array. /// </summary> /// <param name="data"><see cref="byte"/> array to use</param> public V128(byte[] data) { _e0 = (ulong)BitConverter.ToInt64(data, 0); _e1 = (ulong)BitConverter.ToInt64(data, 8); } /// <summary> /// Returns the value of the <see cref="V128"/> as a <typeparamref name="T"/> scalar. /// </summary> /// <typeparam name="T">Type of scalar</typeparam> /// <returns>Value of the <see cref="V128"/> as a <typeparamref name="T"/> scalar</returns> /// <exception cref="ArgumentOutOfRangeException">Size of <typeparamref name="T"/> is larger than 16 bytes</exception> public T As<T>() where T : unmanaged { return Extract<T>(0); } /// <summary> /// Extracts the element at the specified index as a <typeparamref name="T"/> from the <see cref="V128"/>. /// </summary> /// <typeparam name="T">Element type</typeparam> /// <param name="index">Index of element</param> /// <returns>Element at the specified index as a <typeparamref name="T"/> from the <see cref="V128"/></returns> /// <exception cref="ArgumentOutOfRangeException"> /// <paramref name="index"/> is out of bound or the size of <typeparamref name="T"/> is larger than 16 bytes /// </exception> public T Extract<T>(int index) where T : unmanaged { if ((uint)index >= GetElementCount<T>()) ThrowIndexOutOfRange(); // Performs: // return *((*T)this + index); return Unsafe.Add(ref Unsafe.As<V128, T>(ref this), index); } /// <summary> /// Inserts the specified value into the element at the specified index in the <see cref="V128"/>. /// </summary> /// <typeparam name="T">Element type</typeparam> /// <param name="index">Index of element</param> /// <param name="value">Value to insert</param> /// <exception cref="ArgumentOutOfRangeException"> /// <paramref name="index"/> is out of bound or the size of <typeparamref name="T"/> is larger than 16 bytes /// </exception> public void Insert<T>(int index, T value) where T : unmanaged { if ((uint)index >= GetElementCount<T>()) ThrowIndexOutOfRange(); // Performs: // *((*T)this + index) = value; Unsafe.Add(ref Unsafe.As<V128, T>(ref this), index) = value; } /// <summary> /// Returns a new <see cref="byte"/> array which represents the <see cref="V128"/>. /// </summary> /// <returns>A new <see cref="byte"/> array which represents the <see cref="V128"/></returns> public byte[] ToArray() { byte[] data = new byte[16]; Span<byte> span = data; BitConverter.TryWriteBytes(span, _e0); BitConverter.TryWriteBytes(span.Slice(8), _e1); return data; } /// <summary> /// Performs a bitwise logical left shift on the specified <see cref="V128"/> by the specified shift count. /// </summary> /// <param name="x"><see cref="V128"/> instance</param> /// <param name="shift">Number of shifts</param> /// <returns>Result of left shift</returns> /// <remarks> /// This supports shift counts up to 63; anything above may result in unexpected behaviour. /// </remarks> public static V128 operator <<(V128 x, int shift) { if (shift == 0) { return new V128(x._e0, x._e1); } ulong shiftOut = x._e0 >> (64 - shift); return new V128(x._e0 << shift, (x._e1 << shift) | shiftOut); } /// <summary> /// Performs a bitwise logical right shift on the specified <see cref="V128"/> by the specified shift count. /// </summary> /// <param name="x"><see cref="V128"/> instance</param> /// <param name="shift">Number of shifts</param> /// <returns>Result of right shift</returns> /// <remarks> /// This supports shift counts up to 63; anything above may result in unexpected behaviour. /// </remarks> public static V128 operator >>(V128 x, int shift) { if (shift == 0) { return new V128(x._e0, x._e1); } ulong shiftOut = x._e1 & ((1UL << shift) - 1); return new V128((x._e0 >> shift) | (shiftOut << (64 - shift)), x._e1 >> shift); } /// <summary> /// Performs a bitwise not on the specified <see cref="V128"/>. /// </summary> /// <param name="x">Target <see cref="V128"/></param> /// <returns>Result of not operation</returns> public static V128 operator ~(V128 x) => new V128(~x._e0, ~x._e1); /// <summary> /// Performs a bitwise and on the specified <see cref="V128"/> instances. /// </summary> /// <param name="x">First instance</param> /// <param name="y">Second instance</param> /// <returns>Result of and operation</returns> public static V128 operator &(V128 x, V128 y) => new V128(x._e0 & y._e0, x._e1 & y._e1); /// <summary> /// Performs a bitwise or on the specified <see cref="V128"/> instances. /// </summary> /// <param name="x">First instance</param> /// <param name="y">Second instance</param> /// <returns>Result of or operation</returns> public static V128 operator |(V128 x, V128 y) => new V128(x._e0 | y._e0, x._e1 | y._e1); /// <summary> /// Performs a bitwise exlusive or on the specified <see cref="V128"/> instances. /// </summary> /// <param name="x">First instance</param> /// <param name="y">Second instance</param> /// <returns>Result of exclusive or operation</returns> public static V128 operator ^(V128 x, V128 y) => new V128(x._e0 ^ y._e0, x._e1 ^ y._e1); /// <summary> /// Determines if the specified <see cref="V128"/> instances are equal. /// </summary> /// <param name="x">First instance</param> /// <param name="y">Second instance</param> /// <returns>true if equal; otherwise false</returns> public static bool operator ==(V128 x, V128 y) => x.Equals(y); /// <summary> /// Determines if the specified <see cref="V128"/> instances are not equal. /// </summary> /// <param name="x">First instance</param> /// <param name="y">Second instance</param> /// <returns>true if not equal; otherwise false</returns> public static bool operator !=(V128 x, V128 y) => !x.Equals(y); /// <summary> /// Determines if the specified <see cref="V128"/> is equal to this <see cref="V128"/> instance. /// </summary> /// <param name="other">Other <see cref="V128"/> instance</param> /// <returns>true if equal; otherwise false</returns> public bool Equals(V128 other) { return other._e0 == _e0 && other._e1 == _e1; } /// <summary> /// Determines if the specified <see cref="object"/> is equal to this <see cref="V128"/> instance. /// </summary> /// <param name="obj">Other <see cref="object"/> instance</param> /// <returns>true if equal; otherwise false</returns> public override bool Equals(object obj) { return obj is V128 vector && Equals(vector); } /// <inheritdoc/> public override int GetHashCode() { return HashCode.Combine(_e0, _e1); } /// <inheritdoc/> public override string ToString() { return $"0x{_e1:X16}{_e0:X16}"; } private uint GetElementCount<T>() where T : unmanaged { return (uint)(Unsafe.SizeOf<V128>() / Unsafe.SizeOf<T>()); } private static void ThrowIndexOutOfRange() { throw new ArgumentOutOfRangeException("index"); } } }