Computer Hardware User's Guide

D-1
Appendix A
Glossary
A
A0–A23: External address pin s for data/program memory or I/O devices.
These pins are on the primary bus.
address: The location of program code or data stored in memory.
addressing mode: The method by which an instruction interprets its oper-
ands to acquire the data it needs.
ALU: Arithmetic logic unit. The part of the CPU that performs arithmetic and
logic operations.
analog-to-digital (A/D) converter: A converter with internal sample-and-
hold circuitry used to translate an analog signal to a digital signal.
ARAU: Auxiliary-register arithmetic unit. A 32-bit ALU used to calculate indi-
rect addresses using the auxiliary registers as inputs and outputs.
arithmetic logic unit (ALU): The part of the CPU that performs arithmetic
and logic operations.
auxiliary registers (ARn): A set of registers used primarily in address gen-
eration.
auxiliary-register arithmetic unit (ARAU):
Auxiliary-register arithmetic
unit. A 32-bit ALU used to calculate indirect addresses using the auxiliary
registers as inputs and outputs.
B
bit-reversed addressing: Accessing data from memory, registers, and the
instruction word by reversing several bits of an address in order to speed
processing of algorithms, such as Fourier transforms.
Appendix D