This video is about the CPU - Central Processing Unit
Note that the Processor described here is similar to the conceptual one in the course however the registers in the course are referred to as CIR Current Instruction Register (rather than just Instruction Register) and Program Counter or PC Rather than the Instruction Address Register. This processor misses out the MAR (Memory Address and the Memory Buffer Register MBR). You can see that there are several different ways of referring to registers - best to stick to one - the one in the course - This Video is still a useful idea of how a simple processor operates. .
The CPU and Clock Speed
- What is the "Job" of the CPU?
- Instructions have an OPCODE and may have an OPERAND - explain what they are
- What are the three phases of CPU cycle?
- What is the general role of Control Unit?
- What three inputs does the Control Unit send to the ALU to do a calculation?
- What is the purpose of a Clock?
- The Speed that a processor can execute instruction is called the ..................... .......................
- What does 1 Hertz represent?
- How fast was the Intel 4004?
- What can happen when you try to Overclock your CPU clock?
Note All the Instructions that a particular processor can act on - or sees as valid are called the processor instruction set. Some processors are CISC - Complex Instruction Set Computing - with lots of instructions in their set - some are RISC - Reduced Instruction Set Computing - with far less instructions. A RISC processor has to execute more separate instructions but because they are simple they often execute faster. A CISC processor executes on average less instructions but each one takes longer to process.
Describe the Fetch Phase of the cycle you identified above - include the registers and the order of operation.