CPU and memory

• register - small permanent storage location within CPU, data is temporary, size of register are always in byte or bit
• use of register - to handle data, to hold data, to store intermediate values (temporary data)
• CPU (central processing unit) - the brain of the computer, it is responsible for carrying out instructions and managing the flow of data
• components in CPU - ALU (arithmetical logical unit), CU (control unit), RU (register unit, memory unit)
• CU (control unit) - read instructions from memory, ensure the synchronization of data flow and program instruction throughout the computer
• ALU (arithmetical logical unit) - use to perform all arithmetic operation and logical operation
• types of register - GPR/UVR (general purpose register/user visible register), SPR/UIR (special purpose register/user invisible register)
• GPR - AX (accumulator register), BX (base register), CX (counter register), DX (data register), BP (base pointer register), SP (stack pointer register), SI (source index), DI (destination index)
• AX (accumulator register/arithmetic register) - handle addition and subtraction
• BX (base register) - handle base values
• DX (data register) -handle data, perform multiplication and division
• CX (counter register) - count all repeated values
• SPR - IR (instruction register), PSR (program counter register), MAR (memory address register), MDR (memory data register), PSW (program status word/flag register/control register)
• IR (instruction register) - handle current instruction
• PCR (program counter register) - handle address of next instruction
• MAR (memory address register) - handle all memory address
• MDR (memory data register) - handle all memory data
• PSW (program status word/flag register/control register) - indicate the status of CPU
• computer bus - group of electric conductors carries electrical signal from one component to another
• conductor - line/circuit
• type of buses - point to point, multi-point or multi-drop
• RGBY line in CPU - Red (data bus), Green (address bus), Blue (control bus), Yellow (power)
• CPU instruction cycle - fetch (store data and instruction in MDR), decode (divide code into machine understandable format), execute (pass decode instruction as a set of control signals to appropriate components)
• CPU instruction cycle - fetch (store data and instruction in MDR), decode (divide code into machine understandable format), execute (pass decode instruction as a set of control signals to appropriate components)