A method and apparatus for allocating a variable amount of memory to a device coupled to a bus are disclosed. In one embodiment, a first register contains a first value. A second register (e.g., Base Address Register) contains a second value that represents a default amount of memory to allocate to the device. The second value is automatically altered to indicate an updated amount of memory to allocate based on the first value. The ability to alter the default memory value substantially eliminates memory holes, which are unused portions of memory that have been allocated to devices coupled to the bus.