CPU Design Flashcards
What is the overall structure of a computer?
Mainboard, processor, memory, I/O, buses
Name some of the registers in the CPU
ALU, control unit, program counter, MBR, MAR, Instruction register, general purpose registers
What is memory made up of?
A series of addresses and data. A word is one unit of memory (16 bits)
Who and when developed the 6502?
Chuck Peedle, MOS technology, 1975
How many transistors does the 6502 have?
3000 transistors
How does a CPU fetch programs?
Fetch - CPU requests an address from the memory (program counter), the contents of the address get sent to the CPU (instruction register).
How does the CPU decode the programs?
decode - The IR passes the data to a decoder where it turns the data into a physical interaction
How does the CPU execute a program?
The physical interaction is sent to registers where it is executed depending on what it needs (store, load, arithmetic)
What is the control unit?
A machine for execution management, made up of digital logic and driven by a clock
What does the ALU do?
integer operations, Logic operations, Shift operations
What does the PC and the IR do?
Program counter - stores the address of the current instruction
Instruction register - stores the current instruction being executed
What is an instruction made up of?
Opcode, operand
How many different instruction addresses can a 12 bit operand hold?
2^12 addresses
What is an unconditional branch?
Jump to Z, Z = address of next instruction, write Z to program counter
When do we use unconditional branches?
It is used in Vonn Neuman architecture to jump over data in the memory.
Can be used to make an infinite loop.
