1: The CPU

• Coordinates all activities of the CPU • Directs the flow of data between the CPU and other devices • FDE cycle happens here • Sends memory read/write signals to main memory on the control bus

• Holds the address of the next instruction to be executed • Holds a close relationship with MAR: the address held in the PC is copied to the MAR

-Holds the address of the memory location from which data is to be fetched or to which data is to be written -Sends addressed to memory down address bus

• Temporarily stores the data which has been read from or written to memory • All data to and from memory must pass through the MDR via the data bus.

• Holds the current instruction being executed • Contents of MDR are copied into CIR if it is an instruction • Contains opcode and operands of the current instruction • Instruction = opcode + operands

-performs arithmetic and logic functions in the CPU -ADD, SUBTRACT, MULTIPLY, DIVIDE - AND, OR, NOT, XOR - Binary shift -Comparison

• a general purpose register which stores results of calculations performed in the ALU as well as control information • The more general purpose registers a CPU has, the faster it may operate

Carries memory addresses that identify where the data is being read or written to

Carries the binary that make up the actual information being transmitted around the CPU

• Shared memory space for instructions and data • Instructions and data are stored in the same format • A single control unit or processor follows a linear FDE cycle • One instruction at a time • Registers are used as fast access to instructions and data

• Instructions and data stored in separate memory units • each has its own bus • Reading and writing data can be done at the same time as fetching an instruction • Used by RISC processors

• SIMD (Single Instruction Multiple Data): Parallel processing is where a processor carries out a single instruction on multiple data items at the same time - often used by graphic processors • MIMD (Multiple Instructions Multiple Data), another version where multiple instructions are carried on multiple data items across several cores • Distributed computing : Where multiple computers on a shared network each take part on part of a bigger problem

• measured in hertz (Hz) • Number of FDE cycles per second

• Temporary storage of frequently used data and instructions being read to and written from • Located on or near the CPU • Stores copies of recent data and instructions • Quicker to access than RAM, improving efficiency of CPU

• A core is a complete copy of the CPU, with its own separate registers and units • CPUs with multiple cores have more power to run multiple programs at the same time

Small memory cells that operate at very high speeds and used to temporarily store data involved in the FDE cycle.

• Address from the PC is copied to the MAR • Instructions held at that address is copied to the MDR by the data bus • simultaneously the PC is incremented • The value held in the MDR is copied to the CIR

• The contents of CIR are split into opcode and operand

-The opcode is executed on the operand.

add

subtract

store

load

Branch Always