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.
What is a conditional branch?
Only jumps if a condition has been fulfilled, raises a flag for the condition and executes accordingly
What is an assembly language?
Assembly languages translate from high-level languages to machine code.
What is MARIE?
Machine architecture and assembly language, 16 bit accumulator architecture
