Chapter 4 Flashcards
Arithmetic logic unit (ALU)
component in the
processor which carries out all arithmetic and logical
operations.
Control unit
ensures synchronisation of data flow
and programs throughout the computer by sending out
control signals along the control bus.
System clock
produces timing signals on the control
bus to ensure synchronisation takes place.
Accumulator
temporary general purpose register
which stores numerical values at any part of a given
operation.
Register
temporary component in the processor
which can be general or specific in its use that holds
data or instructions as part of the fetch-execute cycle.
Address bus
carries the addresses throughout the
computer system.
Data bus
allows data to be carried from processor to
memory (and vice versa) or to and from input/output
devices.
Control bus
carries signals from control unit to all
other computer components.
BIOS
basic input/output system.
Cache memory
a high speed auxiliary memory which
permits high speed data transfer and retrieval.
Universal Serial Bus (USB)
a type of port connecting
devices to a computer.
Port
external connection to a computer which allows
it to communicate with various peripheral devices. A
number of different port technologies exist.
Program counter (PC)
a register used in a computer
to store the address of the instruction which is
currently being executed.
Current instruction register
a register used to
contain the instruction which is currently being
executed or decoded.
Machine code
the programming language that the
CPU uses.
Instruction
a single operation performed by a CPU.
Assembly language
a low-level chip/machine specific
programming language that uses mnemonics.
Opcode
short for operation code, the part of a
machine code instruction that identifies the action the
CPU will perform.
Operand
the part of a machine code instruction that
identifies the data to be used by the CPU.
Source code
a computer program before translation
into machine code.
Absolute addressing
mode of addressing in which
the contents of the memory location in the operand are
used.
Direct addressing
mode of addressing in which the
contents of the memory location in the operand are
used, which is the same as absolute addressing.
Indirect addressing
mode of addressing in which the
contents of the contents of the memory location in the
operand are used.
Indexed addressing
mode of addressing in which the
contents of the memory location found by adding the
contents of the index register (IR) to the address of the
memory location in the operand are used.
