Assembly Language Programming Glossary

address: The location of the smallest unit of memory that can be directly manipulated by the computer. On the x86 family of CPUs, the address consists of a 16-bit segment and a 16-bit offset within that segment. The CPU combines the segment and offset to get a 20-bit address (when not in the 32-bit mode).
Address arithmetic: Adding an address with a ordinary number to get a new address. It is illegal to add to addresses together or add to ordinary numbers to get a new address.
Arithmetic and Logic Unit (ALU): The part of the CPU that performs computations.
assembler: Program that converts assembly language to object for a specific; type of a CPU. Each type of CPU has to have a unique assembler.
ASCII: American Standard Code for Information Interchange.
assembly lanaguage: A symbolic language that makes programming easier than writing code in machine language. It is not as easy as writing in a higher level language such as C, C++, Java, etc.
binary coded decimal (BCD): Numbers that have been coded in a system where each digit is represented by four bytes (called a nybble). It was used by the business computers when calculating dollars and cents.
binary number: A positional numbering system that uses the powers of two. Binary numbers are used interally by all computers.
bit: A binary digit. Each position in a binary number is represented by a single digit that is either a '0' or a '1'.
boot: The process that a computer system goes through to initialize itself and be prepared to process user programs is known as "booting the computer".
bootstrap: Routines in the ROM used to boot the computer. Comes from the phrase "to pull yourself up by your bootstraps."
byte: A group of eight bits used to hold a value. It is the smallest addressable unit of computer memory. A byte can hold signed values of -128 to 127 or unsigned values from 0 to 255.
character: A symbol (normally in ASCII) used to exchange information. Characters are unsigned values.
CISC: Complex Instruction Set Computer. A type of architecture where a single instruction can perfrom a complex instruction. (As opposed to a RISC architecture where the same work requires several instructions.
computer chip: The CPU is contained in a single Integrated Circuit (IC) computer chip. The chip is typically ¼ to ¾ of an inch but has to be packaged in a much bigger plastic slab. The extra size is necessary for all of the required electical connects.
computer processing unit (CPU): ?
control unit (CU): ??
decimal number: ??
direct memory access (DMA): ??
double word: ??
fetch-execute: ??
general register: ??
firmware: ??
hexidecimal number: ??
I/O device: ??
instruction: ??
instruction pointer: ??
Integrated Circuit (IC): ??
interrupt: ??
interrupt vector: ??
machine cycle: ??
machine language: ??
megaHertz: ??
memory: This is where the computer stores data. There are three levels of memory, main memory (which is connected to the CPU via the system bus) secondary memory (typically a hard disk, which is normally not removable from the system), and tercerary (typically a tape drive, which is normally removable media). Memory is organized as bits (binary digits), bytes (8 bits), word (2 bytes), and double word (2 words).
negative number: ??
one's complement: ??
operation code (OPCODE): ??
quad word: ??
pseudocode: ??
register: ??
RAM: ??
RISC: ??
ROM: ??
ROM BIOS: ??
stack pointer (SP): ??
stored program: ??
two's complement: ??
virtual machine: ??
word: ??

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