3.7.3.1 Flashcards
what is the role of the processor?
the processor is the internal hardware component that is responsible for the executing of instructions and priograms
What are the 5 main components of the processor?
Arithmetic logic unit
clock
control unit
general purpose registers
dedicated registers
What is the ALU and what does the arithemtic logic unit do ?
It performs calculation like addition, subtraction, multiplication, division
it performs logic bitwise operations such as NOT, AND, XOR, OR
it can compare values useing greater than, less than, equal to
it can perform bit shifts to the left and right
What is the control unit and what does the control unit do?
the control unit organises the sequence in which program instructions are executed, and decodes them.
it decodes instructions by analysing the opcode and operand, and coordinating the right components needed to perform the instruction
it uses control signals to do this
how are control signals used
control signals are used by control unit to request use of the data bus and to gran t use of the data bus
it causes data be read and written from/to the address location
it sends the clock signals to synchronise operations
what does the clock do?
the clock emits a constant signal that oscillating between a high voltage one and a low voltage zero to synchronise the components
the time between the end of one rising edge and the start of the next one is the clock period, and is one clock cycle. Performing one instruction can take multiple clock cycles.
what are registers?
registers are small temporary storage spaces within the processor with high read and write speeds
what do general purpose registers do?
They are small temporary storages of memory close to the processor used to store data needed by instructions during execution
what are special purpose reigsters, and what are the 5 special purpose registers?
special purpose registers are registers that are assigned to hold specific information. They are used in the phases of the fetch execute cycle.
they are:
Program counter
Current Instruction Register
Memory address register
memory buffer register
Status register
what do the 5 special registers do?
program counter : stores the adress of the next instruction to be executed
CIR: holds the current instruction the processor is executing
MAR : stores temporarily the address that the processor needs to read or write from
MDR/MBR: stores temporarily the data that is read from or written to the main memory
status register: contains a series of bits that indicate if an error or interrupt has occurred
