Explain an accumulator based central processing unit organization with block diagram.

ALU (Arithmetic Logic Unit):
- Performs arithmetic, shift, and logical operations.
- Handles tasks like addition, subtraction, AND, OR, etc.
Program Counter (PC):
- Keeps track of the memory address of the next instruction to be fetched.
- Guides the CPU to fetch instructions sequentially.
General Purpose Registers (R1, R2, R3):
- Used for storing data temporarily during calculations.
- Inputs are loaded into these registers from memory.
- Results of operations are stored here temporarily before moving them to memory.
Accumulator (ACC):
- Acts as the primary storage register for arithmetic operations.
- It’s where most mathematical operations take place.
Instruction Register (IR) and Decoder:
- IR holds the current instruction fetched from memory.
- The decoder interprets the instruction, determining what operation needs to be performed.
Stack Pointer (SP):
- Manages memory stack transfers during program execution.
- Points to the top of the stack.
Timing and Control Unit:
- Coordinates the timing and sequencing of operations within the CPU.
- Ensures efficient operation and minimizes errors.
Flags:
- Special registers or bits that indicate specific conditions after an operation.
- Examples include the Sign flag (for the sign of the result), Carry flag (for carries in addition or borrows in subtraction), etc.
Bus Sub-system:
- Handles data transfer between memory and CPU registers.
- Facilitates instruction fetches, data transfers, etc.