;A3-3.asm
;將十六進制的ASCII碼轉換為十進制數

STACK1  SEGMENT STACK
         DW 256 DUP(?)
STACK1  ENDS

DDATA	SEGMENT
MES1	DB	'The ascii code of hex are:$'
BUF	    DB	0CH,00H
	    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 	DX,[SI]
	   MOV	BX,SI
	   ADD	BX,2
	   ADD	SI,7
A1:	   DEC 	SI
	   MOV 	AX,DX
	   MOV 	DX,0000H
	   MOV 	CX,000AH
	   DIV 	CX
	   XCHG AX,DX
	   ADD 	AL,30H
	   MOV 	[SI],AL
	   CMP 	DX,0000H
	   JNE 	A1
A2:	   CMP 	SI,BX
	   JZ 	A3
	   DEC 	SI
	   MOV 	AL,30H
	   MOV 	[SI],AL
       JMP 	A2
A3:	   MOV	CX,5
	   MOV	SI,OFFSET BUF
	   ADD	SI,2
	
	   MOV	DX,OFFSET MES1
	   MOV	AH,09H
	   INT	21H
	
A4:	   CALL SHOW
	   MOV	DL,20H
	   MOV	AH,02H
	   INT	21H
	   INC	SI	
	   LOOP	A4

	   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以上的數
	   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