Alternate address for the static vectors (reset and optionally memory errors) which will be used if the appropriate pin is asserted.
Relocatable vectors are arranged with offsets within a 2K byte aligned block of memory. This address is the base of that block for the reset vector and if configured also the memory error vector. As an example, most of the Diamond processors have the primary reset in System ROM, and the alternate reset in Instruction RAM to support different kinds of processor instances.