In
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, 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 base address is a 24-bit value in a general register (extended in steps to 64 bits in
z/Architecture), and the offset is a 12 bit value in the instruction (extended to 20 bits in z/Architecture).
See also
*
Index register
An index register in a computer's central processing unit, CPU is a processor register (or an assigned memory location) used for pointing to operand addresses during the run of a program. It is useful for stepping through String (computer science ...
*
Rebasing
References
Computer memory
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