从键盘输入一个十进制数，二进制显示.asm

汇编程序中的数制转换与DOS调用功能的结合

DATA SEGMENT              ；从键盘输入一个十进制数（<=65535)，转换为十六进制后，
ECH01 DB "INPUT DECIMAL:$"  ；用二进制在屏幕上显示出来
ECH02 DB "HEX RESULT IS:$"
ECH03 DB "TOO BIG!$"
DATA ENDS
CRLF MACRO
        MOV AH,2
        MOV DL,0AH
	INT 21H
	MOV AH,2
	MOV DL,0DH
 	MOV AH,2
	MOV DL,0DH
	INT 21H
	ENDM
CODE SEGMENT
ASSUME CS:CODE
START:  MOV AX,DATA
	MOV DS,AX
REPEAT:	MOV AH,9
	MOV DX,OFFSET ECH01
	INT 21H
	CALL DECBIN
	CRLF
	MOV AH,9
	MOV DX,OFFSET ECH02
	INT 21H
	CALL BINHEX
	CRLF
	JMP REPEAT

DECBIN: MOV BX,0        ；输入与转换
NEW:	MOV AH,1
	INT 21H
	SUB AL,30H
	JB EXIT
	CMP AL,9
	JA EXIT
	CBW
	XCHG AX,BX
	MOV CX,0AH
	MUL CX
	JC error

	XCHG AX,BX
	ADD BX,AX
	JC error
	JMP NEW
EXIT:	RET

error:	mov ah,9
	mov dx,offset ech03
	int 21h
	mov ah,4ch
	int 21h

BINHEX: MOV CH,16     ；输出子句      
	MOV CL,1
REAP:   ROL BX,CL
	MOV DL,BL
        AND DL,1
	CMP DL,0
	JG  PRINT
	
	CMP CH,1      ;假如输入0，输出0
	JNG PRINT

	DEC CH
        JNZ REAP
        JMP OK

RREETT: ROL BX,CL
	MOV DL,BL
	AND DL,1
	
PRINT:  ADD DL,30H
	MOV AH,2
	INT 21H
	DEC CH
	JNZ RREETT
	
OK:	RET

CODE ENDS
END START