All functions in the API-MS-Win-Core-Interlocked-L1-1-0 set are exports from KERNEL32, some from x86 builds only:

All these functions are either forwarded to a corresponding NTDLL function or have an intrinsic implementation in KERNEL32.

New Locations

Both the forwarding and the implementations are duplicated in KERNELBASE version 6.1 and higher.

Schema Redirection

The Windows 7 schema redirects this API Set to KERNELBASE. Thus: