帮忙看看这段代码有什么问题！是打字练习的代码：

DATA SEGMENT INTSEG DW ? INTOFF DW ? Mes1 DB 'Please input a character : $' Mes2 db 'Input character numbers: $' Mes3 db ' Times: $' Mes4 db 0ah,0dh,'$' ICOUNT DB 0 Count db 0 DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX CLI MOV AX,351CH ;调用21H中断的35H子功能保存 INT 21H ;原中断向量 MOV INTSEG,ES MOV INTOFF,BX PUSH DS ;调用21H中断的25H子功能 MOV AX,SEG INTPROC ;设置中断向量表内容 MOV DS,AX MOV DX,OFFSET INTPROC MOV AX,251CH INT 21H POP DS STI MOV DX, OFFSET MES1 CALL DISP SCAN: MOV AH,1 INT 21H INC COUNT CMP AL, 0DH JNZ SCAN CLI MOV DX,INTOFF ;恢复1CH中断向量 MOV AX,INTSEG MOV DS,AX MOV AX,251CH INT 21H MOV DX, OFFSET MES2 CALL DISP MOV AL, COUNT CALL DISPP MOV DX, OFFSET MES4 CALL DISP MOV DX, OFFSET MES3 CALL DISP MOV AL, ICOUNT CALL DISPP STI MOV AH,4CH ;返回DOS INT 21H INTPROC PROC PUSH AX PUSH DS STI MOV AX,DATA MOV DS,AX INC ICOUNT ;中断计数 EXIT: CLI POP DS POP AX IRET INTPROC ENDP DISP PROC MOV AH, 9 INT 21H RET DISP ENDP DISPP PROC PUSH AX MOV CL, 4 SHR AL, CL AND AL, 0FH ADD AL, 30H MOV BL, AL POP AX AND AL,0FH ADD AL, 30H PUSH AX MOV DL , BL MOV AH, 2 INT 21H POP AX MOV DL, AL MOV AH, 2 INT 21H RET DISPP ENDP CODE ENDS END START