I/O:Unit1

编程，从键盘读入学生成绩(0~100分)，共15名学生，计算并显示总分、平均成绩、单的学生成绩

 ;                       sum: avg:
 DATA1    SEGMENT
         STU     DB  ,,,,,,,,,,,,,,
         SUM     DW
         BUF     DB  ,,,
         AVG     DB
         COUNT   EQU
         TIMES   EQU
         BASE    DB
 DATA1    ENDS

 CODE SEGMENT
 MAIN PROC FAR
         ASSUME CS:CODE,DS:DATA1

 START:
         MOV AX,DATA1
         MOV DS,AX

         MOV CX,COUNT
         MOV BX,OFFSET STU
         MOV DL,
 LOOP1:  MOV DH,
         MOV AH,         ;读入数据
         INT 21H
         SUB AL,
         MUL [BASE]
         ADD DH,AL
         MOV AH,
         INT 21H
         SUB AL,
         ADD DH,AL
         MOV [BX],DH
         MOV AH,
         INT 21H
         INC BX
         LOOP LOOP1 

         MOV DL,0DH      ;换行
         MOV AH,
         INT 21H
         MOV DL,0AH
         MOV AH,
         INT 21H

         MOV CX,COUNT
         MOV BX,OFFSET STU
         MOV AL,
         MOV AH,
         CLC
 LOOP2:  ADD AL,[BX]
         ADC AH,
         INC BX
         LOOP LOOP2

         MOV SUM,AX;
         MOV CL,COUNT
         DIV CL
         MOV AVG,AL       

         MOV CX,COUNT        ;输出分数
         MOV BX,OFFSET STU
 LOOP3:  MOV AH,
         MOV AL,[BX]
         DIV [BASE]
         MOV DL,AL
         MOV DH,AH
         ADD DL,
         MOV AH,      ;会影响AL中的数据
         INT 21H
         MOV DL,DH
         ADD DL,
         MOV AH,
         INT 21H
         MOV DL,
         MOV AH,
         INT 21H
         INC BX
         LOOP LOOP3

         MOV DL,0DH      ;换行
         MOV AH,
         INT 21H
         MOV DL,0AH
         MOV AH,
         INT 21H 

         MOV CX,TIMES    ;获取总数逐位
         MOV BX,OFFSET BUF
         MOV AX,[SUM]
 LOOP4:  DIV [BASE]
         MOV [BX],AH
         INC BX
         MOV AH,
         LOOP LOOP4

         MOV DL,  ;显示sum
         MOV AH,
         INT 21H
         MOV DL,
         MOV AH,
         INT 21H
         MOV DL,
         MOV AH,
         INT 21H

         MOV CX,TIMES    ;显示总数
 NEXT1:  DEC BX          ;去前导0
         DEC CX
         MOV DL,[BX]
         CMP DL,
         JE NEXT1

         INC BX
         INC CX

 LOOP5:  DEC BX
         MOV DL,[BX]
         ADD DL,
         MOV AH,
         INT 21H
         LOOP LOOP5

         MOV DL,0DH      ;换行
         MOV AH,
         INT 21H
         MOV DL,0AH
         MOV AH,
         INT 21H 

         MOV DL,
         MOV AH,
         INT 21H
         MOV DL,
         MOV AH,
         INT 21H
         MOV DL,
         MOV AH,
         INT 21H

         MOV AH,
         MOV AL,[AVG]    ;显示平均数
         DIV [BASE]
         MOV DL,AL
         MOV DH,AH
         ADD DL,
         MOV AH,
         INT 21H

         MOV DL,DH
         ADD DL,
         MOV AH,
         INT 21H

 MAIN    ENDP
 CODE    ENDS
         END START