Base address

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

In computing, a base address is a address serving as a reference point ("base") for other addresses.[1] 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).[2][3] A 12-bit offset allows reference to 4096 bytes from a single base. A 20-bit signed offset allows reference to ±512K.

See also

References

<templatestyles src="Reflist/styles.css" />

  1. Script error: No such module "citation/CS1".
  2. Script error: No such module "citation/CS1".
  3. Script error: No such module "citation/CS1".

Script error: No such module "Check for unknown parameters".

Template:Asbox