21.asm

微机原理实验 包括 口令识别 数制转换 计算三角函数 贪食蛇 扬声器控制

DATA SEGMENT
;	SOUND	DB	350,393,441,467,525,589,661
	SOUND	DW	3409,3036,2706,2555,2273,2026,1805
DATA ENDS

STACK SEGMENT STACK
DB 100 DUP(?)
STACK ENDS

CODE SEGMENT
  ASSUME CS:CODE,DS:DATA,SS:STACK
  START:
	MOV AX, DATA
	MOV DS, AX

	MOV DX,2706
	CALL STARTS
	MOV AH,01H	;键盘输入
	INT 21H
	CALL STOPS


EXIT:	MOV AH,4CH
	INT 21H

STARTS	PROC	 ;DX中储存计数初值
	PUSH AX
	IN  AL,61H	;设置控制字
	OR  AL,03H
	OUT 61H,AL
	MOV AX,DX	;设置计数初值
	OUT 42H,AL
	MOV AL,AH	
	OUT 42H,AL
	POP AX
	RET
STARTS	ENDP

STOPS	PROC	;停止发声
	PUSH AX
	IN  AL,61H	
	AND AL,0FCH
	OUT 61H,AL
	POP AX
	RET
STOPS	ENDP

DELY	PROC			;延时子程序， 延时AX*CX
	PUSH	CX
	PUSH	AX
	MOV	AX,0FFFH
X1:	MOV	CX,0FFFFH
X2:	DEC	CX
	JNE	X2
	DEC	AX
	JNE	X1
	POP	AX
	POP	CX
	RET
DELY	ENDP

CODE ENDS
END START