The Unity.Burst.Intrinsics.Common intrinsics are for functionality shared across the hardware targets that Burst supports.
Unity.Burst.Intrinsics.Common.Pause is an intrinsic that requests that the CPU pause the current thread. It maps to pause on x86, and yield on ARM.
Use it to stop spin locks over contending on an atomic access, which reduces contention and power on that section of code.
The Unity.Burst.Intrinsics.Common.Prefetch is an intrinsic that provides a hint that Burst should prefetch the memory location into the cache.
Use the Unity.Burst.Intrinsics.Common.umul128 intrinsic to access 128-bit unsigned multiplication. These multiplies are useful for hashing functions. It maps 1:1 with hardware instructions on x86 and ARM targets.
The Unity.Burst.Intrinsics.Common.InterlockedAnd and Unity.Burst.Intrinsics.Common.InterlockedOr are intrinsics that provides atomic and/or operations on int, uint, long, and ulong types.