帮忙改一下代码错误，有四个错误

1．测试练习打字速度

要求:

（1）屏幕提示字符,键盘输入字符,回车结束.

（2）用日时钟中断,55 ms定时.

DATA SEGMENT

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