base-bound register
base-bound register (base-limit register) Hardware used for virtual-memory allocation. A base-bound register is associated with each segment of data or code and defines the position in physical memory of word zero for that segment, the so-called base, and the number of words available to that segment, the so-called bound or limit (or alternatively the physical memory address of the next word after the end of the segment, in which case it is a bounds register). Whenever a process attempts to access the memory segment, the hardware of the system checks that the address of the word lies within the range 0 ← word address < bound
and then adds the address to the value contained in the base register to give the physical address. A restriction on this system is that the storage for the segment must be allocated in a contiguous area of memory (see best fit, first fit).
The base register, used in the construction of relative addresses, should not be confused with the base of a base-bound system; the result of modifying an address by a base register's contents is still an address within virtual memory space of the process, and is not necessarily a physical address.
and then adds the address to the value contained in the base register to give the physical address. A restriction on this system is that the storage for the segment must be allocated in a contiguous area of memory (see best fit, first fit).
The base register, used in the construction of relative addresses, should not be confused with the base of a base-bound system; the result of modifying an address by a base register's contents is still an address within virtual memory space of the process, and is not necessarily a physical address.
More From encyclopedia.com
Virtual Memory , Virtual memory is a model—one of many possible models—for managing the resource of physical memory, or main memory. Such management is necessary beca… Memory , Memory is involved in almost every aspect of children's behavior, from everyday occurrences such as finding a misplaced toy, through the routine dema… Cache , cache (cache memory) A type of memory that is used in high-performance systems, inserted between the processor and memory proper. The memory hierarch… Semantic Memory , In 1972 the cognitive scientist Endel Tulving (b. 1927) argued that conscious recollection (i.e., declarative memory) is composed of two separate mem… Base , base1 / bās/ • n. 1. the lowest part or edge of something, esp. the part on which it rests or is supported: she sat down at the base of a tree. ∎ Arc… Base Analogue , base analogue A purine or pyrimidine base (see BASE PAIR) that differs slightly in structure from the normal base, but that because of its similarity…
You Might Also Like
NEARBY TERMS
base-bound register