Burst provides support for some of the System namespace, transforming these into Burst compatible variants in the Burst compiler.
Burst supports all methods that System.Math declares, with the following exceptions:
double IEEERemainder(double x, double y) is only supported when Api Compatibility Level is set to .NET Standard 2.1 in project settingsBurst supports all methods of System.IntPtr/System.UIntPtr, including the static fields IntPtr.Zero and IntPtr.Size
Burst supports atomic memory intrinsics for all methods provided by System.Threading.Interlocked (for example, Interlocked.Increment).
Make sure that the source location of the interlocked methods are naturally aligned. For example, the alignment of the pointer is a multiple of the pointed-to-type:
[StructLayout(LayoutKind.Explicit)]
struct Foo
{
[FieldOffset(0)] public long a;
[FieldOffset(5)] public long b;
public long AtomicReadAndAdd()
{
return Interlocked.Read(ref a) + Interlocked.Read(ref b);
}
}
If the pointer to the struct Foo has an alignment of 8, which is the natural alignment of a long value, the Interlocked.Read of a would be successful because it lies on a naturally aligned address. However, b would not be successful and undefined behavior happens at the load of b as a result.
Burst supports the MemoryBarrier method of System.Threading.Thread.
Burst supports the non-generic variants of Read and Write provided by System.Threading.Volatile.
Burst supports all methods of HashCode except for HashCode.Add<T>(T, IEqualityComparer<T>).
However, Burst does not guarantee compatibility of results with the .NET implementation. As a consequence, HashCode functions might produce different results when running in Burst versus other runtime environments such as Mono.
For example, the value produced by HashCode.Combine is different when run on Burst compared to managed code, because Burst doesn’t have access to the seed value used by the managed implementation.