43 lines
1.5 KiB
Markdown
43 lines
1.5 KiB
Markdown
|
# Intrinsics
|
||
|
|
|
||
|
|
## `System.Math`
|
||
|
|
|
||
|
|
Burst provides an intrinsic for all methods declared by `System.Math` except for the following methods that are not supported:
|
||
|
|
- `double IEEERemainder(double x, double y)`
|
||
|
|
- `Round(double value, int digits)`
|
||
|
|
|
||
|
|
## `System.IntPtr`
|
||
|
|
|
||
|
|
Burst supports all methods of `System.IntPtr`/`System.UIntPtr`, including the static fields `IntPtr.Zero` and `IntPtr.Size`
|
||
|
|
|
||
|
|
## `System.Threading.Interlocked`
|
||
|
|
|
||
|
|
Burst supports atomic memory intrinsics for all methods provided by `System.Threading.Interlocked` (e.g `Interlocked.Increment`...etc.)
|
||
|
|
|
||
|
|
Care must be taken when using the interlocked methods that the source location being atomically accessed is _naturally aligned_ - e.g. the alignment of the pointer is a multiple of the pointed-to-type.
|
||
|
|
|
||
|
|
For example:
|
||
|
|
|
||
|
|
```c#
|
||
|
|
[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);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
Let's assume that the pointer to the struct `Foo` has an alignment of 8 - the natural alignment of a `long` value. The `Interlocked.Read` of `a` would be successful because it lies on a _naturally aligned_ address, but `b` would not. Undefined behaviour will occur at the load of `b` as a result.
|
||
|
|
|
||
|
|
## `System.Threading.Thread`
|
||
|
|
|
||
|
|
Burst supports the `MemoryBarrier` method of `System.Threading.Thread`.
|
||
|
|
|
||
|
|
## `System.Threading.Volatile`
|
||
|
|
|
||
|
|
Burst supports the non-generic variants of `Read` and `Write` provided by `System.Threading.Volatile`.
|