2.1.3双字节有符号数加法.txt

本人保存经典的51程序

DADD:
MOV	A,R3			
MOV	C,ACC.7
MOV    	SR0,C
XRL    	A,R6
MOV    	C,ACC.7
MOV    	A,R3
CLR    	ACC.7
MOV    	R3,A
MOV    	A,R6
CLR    	ACC.7
MOV    	R6,A
JC     	DAB2
LCALL  	NADD
MOV    	A,R3
JB     	ACC.7,DABE
DAB1:
MOV    	C,SR0
MOV    	ACC.7,C
MOV    	R3,A
CLR    	OV
RET
DABE:
SETB   	OV
MOV    	A,R3
JNB   	 ACC.7,DAB1
CMPT:
MOV	A,R4							
CPL 		A
ADD		A,#01H
MOV	R4,A
MOV	A,R3
CPL		A
ADDC	A,#00H
MOV	R3,A							
CPL		SR0
SJMP	DAB1
RET