RAX(64bit) -> EAX(32bit) -> AX(16bit) -> AH(8bit - high) - AL(8bit - low) Accumulator for operands and results data 주로 곱셈, 나눗셈에 사용되며, 함수의 반환값을 저장(리턴값) RBX(64bit) -> EBX(32bit) -> BX(16bit) -> BH(8bit - high) - BL(8bit - low) Pointer to data in the DS segment ESI, EDI 와 결합해 인덱스에 사용됨. RCX(64bit) -> ECX(32bit) -> CX(16bit) -> CH(8bit - high) - CL(8bit - low) Counter for string and loop operations 반..