A region is a user-defined area on a chip into which you can constrain the physical placement of one or more macros. You can also constrain macros containing multiple tiles for cores, RAMs, and I/Os. The floorplanning process usually requires you to create several regions and assign logic to them. Logic can include core logic, memory, and I/O modules. When you run the place-and-route tool, it places the logic into their assigned regions.
Some regions are user-defined and others are automatically created by the tools to meet routing requirements (for example, Local clock regions).
You can use region constraints to:
Create user-defined regions such as Inclusive, Exclusive, Empty, LocalClock, and QuadrantClock
Assign and unassign macros to user-defined regions
Constrain all the macros connected to a net by assigning them to a specific net region
Move regions from one set of co-ordinates to another