MCS-51单片机应用子程序：2.2.2多字节无符号数减法

MOV R0, #30H MOV R1, #10H MOV R7,#3 CLR C LOOP: MOV A, @R0 SUBB A, @R1 MOV @R1, A INC R0 INC R1 DJNZ R7, LOOP RET