把将yaffs 移植到 ucos 系统， 为此lwip 中剥离出内存管理函数mem.c 以弥补ucos内存管理函数的不足。-will put yaffs CENTER transplant system, this lwip were removed from the memory management functions mem.c to cover CENTER memory management function deficiencies.

ucos系统下对mem管理的操作程序，基于C语言编程-ucos system operating procedures for mem management, based on C language programming