16-7-4-2.asm

51单片机开发与应用技术详解(珍藏版)PPT及源码

		ORG		0000H
		JMP		START
		ORG		1000H
START:	MOV		20H,#0FFH 		;赋RAM的20H单元为0xFF
		JB		20H.0,FUN1		;若bit=1，则跳转
FF1:		MOV		21H,#00H			;赋值
		JNB		21H.0,FUN2		;若bit=0，则跳转
FF2:		MOV		22H,#80H			;赋值
		JBC		22H.7,FUN3		;跳转

FUN1:	MOV		30H,#0ABH		;片内RAM的30H单元赋值
		JMP		FF1
FUN2:	MOV		31H,#0CDH		;片内RAM的31H单元赋值
		JMP		FF2
FUN3:	MOV		32H,#0EFH		;片内RAM的32H单元赋值

		RET
		END
		ORG		0000H
		JMP		START
		ORG		1000H
START:	MOV		PSW,#80H 		;赋CY=1
		JC		FUN1			;若CY=1，则跳转
FF1:		MOV		PSW,#00H		;赋CY=0
		JNC		FUN2			;若CY=0，则跳转

FUN1:	MOV		20H,#0ABH		;片内RAM的20H单元赋值
		JMP		FF1
FUN2:	MOV		21H,#0CDH		;片内RAM的21H单元赋值

		RET
		END