Ada Programming/Libraries/System.Multiprocessors

is a unit of the Predefined Language Environment since Ada 2012.

Specification
PreelaborateMultiprocessors CPU_Range  0  implementation_defined Not_A_Specific_CPU  CPU_Range  0 CPU CPU_Range  1  CPU_Range Number_Of_CPUs CPU SystemMultiprocessors

Wikibook

 * Ada Programming/Libraries/System