COMPAR:
CLR C ;进位标志清零
MOV A,50H ;50H值送A
CJNE A,51H,COMP ;比较A与51H值大小
COMP: JC COMP1 ;如果50H<51H转COMP1
JB ACC.7,COMP01 ;判50H的正负
MOV A,51H ;50H为正
JB ACC.7,COMP02 ;判51H正负
MOV 60H,50H ;50H，51H均为正，50H大送60H
GOTO OKS ;
COMP01: MOV 60H,51H ;50H为负，但50H>51H，所以51H无论正负均大
GOTO OKS
COMP02:MOV 60H,51H ;50H，51H均负，值小为大
GOTO OKS
COMP1: JB ACC.7,COMP10 ;判50H正负
MOV A,51H ;50H为正
JB ACC.7,COMP11 ;判51H正负
MOV 60H,51H ;均正，51H大
GOTO OKS
COMP10:MOV 60H,50H ;50H负，值小为大
GOTO OKS
COMP11:MOV 60H,50H ;均负，值下为大
OKS:RET
