computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ...

, a base address is an

address An address is a collection of information, presented in a mostly fixed format, used to give the location of a building, apartment, or other structure or a plot of land, generally using border, political boundaries and street names as references, ...

serving as a reference point ("base") for other addresses. Related addresses can be accessed using an ''addressing scheme''. Under the ''relative addressing'' scheme, to obtain an

absolute address In computing, a memory address is a reference to a specific memory location in memory used by both software and hardware. These addresses are fixed-length sequences of digits, typically displayed and handled as unsigned integers. This numeric ...

, the relevant base address is taken and an offset (aka displacement) is added to it. Under this type of scheme, the base address is the lowest numbered address within a prescribed range, to facilitate adding related positive-valued offsets. In

IBM System/360 architecture The IBM System/360 architecture is the model independent architecture for the entire S/360 line of mainframe computers, including but not limited to the instruction set architecture. The elements of the architecture are documented in the ''IB ...

, the base address is a 24-bit value in a general register (extended in steps to 64 bits in

z/Architecture z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture ...

), and the offset is a 12 bit value in the instruction (extended to 20 bits in z/Architecture).

References

Computer memory {{Compu-hardware-stub

See also

References