8051运算类子程序，包括双字节乘法子程序、多字节数乘10子程序、多字节无符号数出除法子程序、多字节ＢＣＤ码减法子程序、多字节ＢＣＤ码取补子程序、多字节ＢＣＤ码左移十进制一位（乘十）子程序。-8051 subroutine computing category, including double-byte multiplication subroutine, multi-byte count by 10 subroutines, multi-byte unsigned number of the