【正文】 JJ2 MOV 42H, 0AH 。次高位不亮，次次高位也不亮JJ2: MOV 43H, R0 POP B POP PSW POP ACC RET※※※※※※2字節(jié)無符號數(shù)乘法程序※※※※※※R7R6R5R4≦R3R2R1R0MUL2BY2: CLR A MOV R7,A MOV R6,A MOV R5,A MOV R4,A MOV 46H,10HMULLOOP1: CLR C MOV A,R4 RLC A MOV R4,A MOV A,R5 RLC A MOV R5,A MOV A,R6 RLC A MOV R6,A MOV A,R7 RLC A MOV R7,A MOV A,R0 RLC A MOV R0,A MOV A,R1 RLC A MOV R1,A JNC MULLOOP2 MOV A,R4 ADD A,R2 MOV R4,A MOV A,R5 ADDC A,R3 MOV R5,A MOV A,R6 ADDC A,00H MOV R6,A MOV A,R7 ADDC A,00H MOV R7,AMULLOOP2: DJNZ 46H,MULLOOP1 RET ※※※※※※4字節(jié)/2字節(jié)無符號數(shù)除法程序※※※※※※；R7R6R5R4/R3R2=R7R6R5R4(商)…R1R0(余數(shù))DIV4BY2: MOV 46H,20H MOV R0,00H MOV R1,00HDIVLOOP1: MOV A,R4 RLC A MOV R4,A MOV A,R5 RLC A MOV R5,A MOV A,R6 RLC A MOV R6,A MOV A,R7 RLC A MOV R7,A MOV A,R0 RLC R0 MOV R0,A MOV A,R1 RLC A MOV R1,A CLR C MOV A,R0 SUBB A,R2 MOV B,A MOV A,R1 SUBB A,R3 JC DIVLOOP2 MOV R0,B MOV R1,ADIVLOOP2: CPL C DJNZ 46H,DIVLOOP1 MOV A,R4 RLC A MOV R4,A MOV A,R5 RLC A MOV R5,A MOV A,R6 RLC A MOV R6,A MOV A,R7 RLC A MOV R7,A RET END 。