Registers

 

Register	Type	Function	Notes / Usage
AX / A, B, C, D, E, H, L	General-Purpose	Store temporary data, results of arithmetic/logic	AX often used as accumulator, CX as counter, BX as base, DX for I/O
PC (Program Counter)	Special-Purpose	Holds address of next instruction to fetch	Increments automatically; controls instruction sequence
IR (Instruction Register)	Special-Purpose	Holds current instruction being executed	Decoded by control unit for execution
MAR (Memory Address Register)	Special-Purpose	Holds memory address to read/write	Works with memory during fetch/store cycles
MBR / MDR (Memory Buffer/Data Register)	Special-Purpose	Holds data read from or to be written to memory	Acts as buffer between CPU and memory
SP (Stack Pointer)	Special-Purpose	Points to top of stack	Used for push/pop, subroutine calls, interrupts
FLAGS / Status Register	Special-Purpose	Stores condition codes (Zero, Carry, Sign, Parity, Overflow)	Updated after arithmetic/logical operations; guides conditional branching