谢谢啦

有时候要用到寄存器的时候，但是却不知用哪个，请问 AX，BX，CX，DX，与 SP，BP，SI，DI 以及 CS，DS，SS，ES这个几个应该怎样区别？

DATA SEGMENT
TABLE DW 41H,58H,42H,50H,5AH,44H,55H,42H,'$'
LEN DW 16
DATA ENDS

CODE SEGMENT
ASSUME CS:CODE, DS:DATA

MAIN PROC FAR
PUSH DS
MOV AX,0
PUSH AX
MOV AX, DATA
MOV DS, AX

CALL FAR PTR DISP
MOV DL, 0DH ;DISPLAY THE NEW LINE
MOV AH, 2
INT 21H
MOV DL, 0AH
MOV AH, 2
INT 21H

LP1: MOV BX, 1 ;SET FLAG, IF 1, NOT FINISHED
MOV CX, LEN ;TIMES OF INTERATION
DEC CX
MOV SI, OFFSET TABLE

LP2: MOV AX, [SI]
CMP AX, [SI+2]
JBE NEXT
XCHG AX, [SI+2]
MOV [SI], AX
XOR BX, BX ;IF XCHG HAPPENS, SET BX TO 0

NEXT: ADD SI, 2
LOOP LP2
DEC LEN
CMP BX, 1
JNZ LP1
JMP SHORT EXIT

DISP: MOV DX, OFFSET TABLE
MOV AH, 9
INT 21H
RET

EXIT: CALL FAR PTR DISP
MOV AX, 4C00H
INT 21H
MAIN ENDP
CODE ENDS
END MAIN
程序是把字母输出并排序，但是运行时却有错误，请问错在哪里呢？