Instruction Address Register

instruction address register

[in′strək·shən ə¦dres ′rej·ə·stər]

(computer science)

A special storage location, forming part of the program controller, in which addresses of instructions are stored in order to control their sequential retrieval from memory during the execution of a program.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Instruction Address Register

(IAR) The IBM name for program counter.

The IAR can be accessed by way of a supervisor call in supervisor state, but cannot be directly addressed in problem state.

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