WELCOME TO PINOY TEAM TALK COMMUNITY


You'll need to login in order to fully use all
the featured and view all the sectionsof this site.

Please register if you're not yet a member.







 
HomePORTALRegisterLog in

 

 An index register[NB 1]

View previous topic View next topic Go down 
Author Message
jukido
TEAM TALK
TEAM TALK
avatar

Reputation : 0

PostSubject: An index register[NB 1]   Mon Aug 01, 2011 6:47 pm

An index register[NB 1] in a computer's CPU is a processor register used for modifying operand addresses during the run of a program, typically for doing vector/array operations. Index registers were first used in the British Manchester Mark 1 computer, in 1949.

Index registers are used for a special kind of indirect addressing where an immediate constant (i.e. which is part of the instruction itself) is added to the contents of a register to form the address to the actual operand or data; architectures which allow more than one register to be used this way naturally have an opcode field for specifying which register to use.

In early computers without any form of indirect addressing, array operations had to be performed either by linearly repeating program code for each array element (i.e. over all address locations), or by using rather "dirty" self-modifying code techniques – both alternatives leading to quite significant disadvantages in program flexibility and maintenance, as well as being wasteful of computer memory; the latter a very scarce resource in computer installations of the early era (as well as in early microcomputers several decades later).o

Corporate sports bags
ares download free
Back to top Go down
View user profile
 

An index register[NB 1]

View previous topic View next topic Back to top 
Page 1 of 1

Permissions in this forum: You cannot reply to topics in this forum
 :: General Talk :: New Member Introduction -
Full Size image preview:
Free forum hosting | © phpBB | Free forum support | Contact | Report an abuse | Free forum