a3-1.asm

A1.asm 显示程序实验 STACK1 SEGMENT STACK DW 256 DUP(?) STACK1 ENDS DATA SEGMENT USE16 MES1 DB

;A3-1.asm
;将ASCII码十进制数转换为二进制数

STACK1  SEGMENT STACK
         DW 256 DUP(?)
STACK1  ENDS

DDATA	SEGMENT
MES1    DB    'The ascii code of decimal code are:$'
BUF     DB    30H,30H,30H,31H,32H
        DB    10H DUP(0)
DDATA	ENDS

CODE SEGMENT
	ASSUME CS:CODE,DS:DDATA
	
START:  MOV  AX,DDATA
        MOV  DS,AX

        MOV  SI,OFFSET BUF
        MOV  BX,000AH
        MOV  CX,0004H
        MOV  AH,00H
        MOV  AL,[SI]
        SUB  AL,30H
A1:	    IMUL BX
        ADD  AL,[SI+01]
        SUB  AL,30H
        INC  SI
        LOOP A1
        MOV  [SI],AX
        MOV  DX,OFFSET MES1
        MOV  AH,09H
        INT  21H
        INC  SI                      ;显示高字节
        CALL SHOW
        DEC  SI                      ;显示低字节
        CALL SHOW

        MOV  AX,4C00H
        INT  21H
	
SHOW    PROC NEAR
        MOV  AL,DS:[SI]
        AND  AL,0F0H                 ;取高4位
        SHR  AL,4
        CMP  AL,0AH                  ;是否是A以上的数
        JB   C2       
        ADD  AL,07H   
C2:     ADD  AL,30H   
        MOV  DL,AL                   ;show character 
        MOV  AH,02H
        INT  21H
        MOV  AL,DS:[SI]
        AND  AL,0FH                  ;取低4位
        CMP  AL,0AH
        JB   C3
        ADD  AL,07H
C3:     ADD  AL,30H
        MOV  DL,AL                   ;show character 
        MOV  AH,02H
        INT  21H
	    RET
        ENDP
CODE ENDS
     END START