;A8-2.asm
;綜合程序設計實驗－碼制轉換實驗

.386
STACK1  SEGMENT STACK   USE16 
	DB	64	DUP(?)
STACK1  ENDS

DATA	SEGMENT	USE16
MES0    DB   'This is tangdu speaking!$'
MES1	DB	 'Show this sentence as hex:$'
BUF     DB   65    DUP(?)
DATA	ENDS

CODE	SEGMENT	USE16
	ASSUME	CS:CODE,DS:DATA
	
START: MOV 	AX,DATA
	   MOV	DS,AX

	   MOV	DX,OFFSET MES0	       ;Show "This is tangdu speaking!"
	   MOV	AH,09H
	   INT 	21H
	   CALL	KENTER			
	   MOV	DX,OFFSET MES1	       ;Show Sentence as hex
	   MOV	AH,09H
	   INT 	21H
	   CALL	KENTER	
	   CALL	SAHEX
	   MOV	DX,OFFSET BUF
	   MOV	AH,09H
	   INT 	21H
	   CALL	KENTER	

	   MOV	AH,4CH
	   INT	21H

SAHEX	PROC	NEAR
CBYTE   =24
	   PUSHAD				      ;將所有32位寄存器壓棧
	   MOV	DI,OFFSET MES0
	   MOVZX EDI,DI			      ;零擴展指令
	   MOV	AX,DATA
	   MOV	GS,AX			      ;使用GS段
	   MOV	SI,OFFSET BUF
	   MOVZX ESI,SI
	   MOV	ECX,CBYTE
C1:	   MOV	AL,DS:[EDI]
	   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	GS:[ESI],AL
	   MOV	AL,DS:[EDI]
	   AND	AL,0FH			      ;取低4位
	   CMP	AL,0AH
	   JB	C3
	   ADD 	AL,07H
C3:	   ADD	AL,30H
	   MOV	GS:[ESI+1],AL
	   MOV	BYTE PTR GS:[ESI+2],20H	;在每個字符間加入空格
	   ADD	ESI,3
	   INC	EDI
	   LOOP	C1
	   MOV	BYTE PTR GS:[ESI],24H	;在串尾加上$符
	   POPAD				      ;彈出所有寄存器值
	   RET
SAHEX	ENDP

KENTER	PROC	NEAR
	   MOV	DL,0AH
	   MOV	AH,02H
	   INT	21H
	   MOV	DL,0DH
	   MOV	AH,02H
	   INT	21H
	   RET
KENTER	ENDP
CODE  ENDS
	   END	START