Registers are the internal memory locations which are used as variables. Using registers instead of memory to store values makes the process faster. Very broadly there are four types of Registers they are General purpose registers, index registers, segment registers, pointer registers, and indicator register.
General purpose registers:
EAX, EBX, ECX, EDX.
Index registers:
ESI, EDI.
Segment registers:
CS, DS, ES, FS, GS, SS.
Pointer registers:
EIP, ESP, EBP.
Indicator register:
EFLAGS.
Functions of some Registers:
Register Function
EAX Stores the return value.
EBX Base pointer for memory access.
ECX Counter for loop counter and strings.
EDX io pointer and arithmetic.
ESI source pointer for string operations
EDI Destination pointer for string operations
EIP Points to next instruction address to be executed.
ESP Stack pointer
EBP Base pointer and holds the base address of the stack.
Paruchuri Rakesh 