Page 38 - DCAP210_INTRODUCTION__TO_MICROPROCESSORS

Introduction to Microprocessors

Notes 2.5 Summary

• Every computer has at its heart exactly two things: a CPU and some memory.
• A computer program is nothing more than a collection of numbers stored in memory.
• Different numbers tell the CPU to do different things.

• Inside the CPU are a number of locations, called registers, which can store a number.
• An interrupt is used to stop one program and execute another in its place.
• Debug is a powerful utility that lets you directly access the registers and memory of your
computer for various purposes.

2.6 Keywords
An assembler is a special program that takes the programmer’s words and converts them to
numbers that the computer could understand.
An interrupt is used to stop one program and execute another in its place.

Comments are messages intended only for human consumption. They have no effect on the
translation process and indeed are not acted on by the LC-3b Assembler.
Labels: Memory locations will be given symbolic addresses called labels.

OPCODE: It is a symbolic name for the opcode of the corresponding LC-3b instruction.

1. Give the address of following symbols in assembly:
TEST, GETCHAR
2. Differentiate between Opcodes and Operands.

2.7 Self-Assessment Questions

1. A computer program is a collection of .......................... stored in memory.
(a) data (b) program

(c) numbers (d) alphabets
2. The CPU reads the numbers one at a time, .......................... them, and does what the numbers
say.

(a) codes (b) decodes
(c) find (d) elaborates
3. .......................... is a powerful utility that lets you directly access the registers and memory
of your computer for various purposes.
(a) Debug (b) Assemble

(c) Cursor (d) None of these
4. What is a symbolic name for the opcode of the corresponding LC-3b instruction?
(a) OPERANDS (b) OPCODE
(c) LDW (d) None of these

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