When using PCI Express, can 32-bit addressing be used to access the lower 4GB memory space of a 64-bit BAR?

Description

If the 64-bit BAR is greater than 4GB in size, then 64-bit addressing must be used to access the BAR as its assigned address space must be located above the 32-bit 4GB address space.

If the 64-bit BAR is smaller than 4GB in size, then it may be located below the 32-bit 4GB address space, and 32-bit addressing may be used.