Xorshift64 for Burst

NativeXorshift64.cs

using UnityEngine;
using Unity.Burst;
using Unity.Collections;
using Unity.Collections.LowLevel.Unsafe;
using System.Threading;

public unsafe struct NativeXorshift64 {
	[NativeDisableUnsafePtrRestriction]
	public ulong *y;

	public Allocator label;

	public NativeXorshift64(ulong seed, Allocator allocator) {
		label = allocator;

		y = (ulong *)UnsafeUtility.Malloc(sizeof(ulong), UnsafeUtility.AlignOf<ulong>(), label);
		*y = seed;
	}

	public void Dispose() {
		UnsafeUtility.Free(y, label);
	}

	public ulong Next() {
		ulong i, c;
		do {
			c = i = *y;

			c = c ^ (c << 13);
			c = c ^ (c >> 17);
			c = c ^ (c << 15);
		} while ((long)i != Interlocked.CompareExchange(ref *((long *)y), (long)c, (long)i));

		return c;
	}
}