NIMCET 2009 — Computer PYQ
NIMCET | Computer | 2009Index register in a digital computer is used for
Choose the correct answer:
- A.
pointing to the stack address.
- B.
indirect addressing.
- C.
keeping track of the number of times loop is executed.
- D.
address modification.
(Correct Answer)
address modification.
Explanation
In computer architecture, an Index Register is a processor register used specifically for modifying operand addresses during the execution of a program.
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Address Modification: The primary function of an index register is to hold a numerical value that is added to (or subtracted from) the address part of an instruction to determine the effective address of the operand. This is known as Indexed Addressing.
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Effective Address Calculation: The formula used is typically Effective Address=Base Address+Index Register Content.
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Common Usage: It is extensively used for accessing elements within arrays or tables. By changing the value in the index register, the same instruction can access different memory locations in a sequence.
