Processor Architecture & Interfacing - Unit I

Vocabulary flashcards covering microprocessor architecture, computer types, programming tools, and NASM assembler directives based on Unit I lecture notes.

Mainframes

The largest and most powerful computers with a data word length of $64$ bits or more, used for complex scientific calculations and military defense control.

Minicomputers

A scaled-down version of a mainframe computer designed to process smaller data words of $32$ bits.

Microcomputers

Small computers containing a single CPU (MPU) that operate at word lengths of $4$, $8$, $16$, or $32$ bits; examples include the Intel $8051$.

Microprocessor

A general-purpose digital CPU on a single chip.

Firmware

A type of software embedded in hardware that provides basic instructions and system controls to help hardware start up and perform basic input/output tasks.

Von Neumann Architecture

A computer architecture where both program and data are stored in the same memory unit and instructions are executed in a sequential fashion.

Harvard Architecture

A computer architecture with physically separate storage and signal pathways for instructions and data, allowing the CPU to read both simultaneously.

CISC

Complex Instruction Set Computer; features a large number of instructions ($200$ to $300$), variable length formats, and emphasizes hardware to maximize performance.

RISC

Reduced Instruction Set Computer; features relatively few instructions (around $50$), fixed length formats, and relies on software and pipelining for performance.

Machine Language

The lowest-level language consisting of strings of $1$'s and $0$'s that a processor understands directly.

Assembly Language

A low-level, processor-dependent language that represents machine instructions using symbolic codes called mnemonics.

Assembler

A tool that translates a source file into binary or object code through two passes, creating an object file and a list file.

Linker

A program used to join several object files into one large, re-locatable executable file and produce a link map.

Absolute Loader

A type of loader that brings a file into memory at a specific location outlined in the file header without performing relocation.

Relocating Loader

A loader that determines the location of a program in memory and calculates relative offsets, which may produce a delay.

Locator

A program (such as EXE2BIN) used to assign specific physical addresses to segments of object code for loading into memory.

Debugger

A program that allows a user to load object code, set breakpoints, and execute instructions one by one to check and alter memory or register contents.

Emulator

A combination of hardware and software used to substitute, test, and debug the internal behavior of an external system.

Simulator

A software-only tool used to study and analyze different environments using high-level languages, typically faster than emulators due to a lack of binary translation.

Assembler Directives

Non-executable statements (pseudo-ops) that control the assembly process and layout of the program but do not generate machine code.

.STACK [size]

An assembler directive used to define the stack size; the default size is $1024$ bytes.

DB (Define Byte)

A directive that allocates $1$ byte of storage; range is $-128$ to $+127$ (signed) or $0$ to $255$ (unsigned).

DW (Define Word)

A directive that allocates $1$ word ($2$ bytes) of storage; range is $-32,768$ to $+32,767$ (signed) or $0$ to $65,535$ (unsigned).

DQ (Define Quadword)

A directive used to reserve or declare variables that are $4$ words ($8$ bytes) in length.

DT (Define Ten Bytes)

A directive that defines data items $10$ bytes long and stores data directly in decimal form.

DUP Operator

A duplicate operator used with storage allocation directives (DB, DW, etc.) to repeat values for tables or arrays.

EQU (Equate)

A directive used to assign a name to a value or symbol, which the assembler replaces throughout the program.

%assign

A case-sensitive NASM directive used to define numeric constants that allows for redefinition.

%define

A NASM directive, similar to #define in C, used to define both numeric and string constants which can be redefined.

EXTRN

A directive signaling that labels or names follow are located in a different assembly module.

OFFSET

An operator that tells the assembler to determine the distance (in bytes) from a base starting location to a specific data element or memory address.

ORG (Originate)

A directive that sets the location counter to a specific value; uses symbol $S$ to represent the current value of the location counter.

Near Procedure

A procedure declared in the same segment as the main program; only the IP is pushed to the stack during a call.

Far Procedure

A procedure declared in a different segment than the main program; both the IP and CS are pushed to the stack during a call.

Macros

A text substitution mechanism used to reduce repetitive coding; the machine code is regenerated every time it is called.

NASM

Netwide Assembler; a popular assembler for the Intel x86 architecture used in Linux, originally written by Simon Tatham.