blackfin平台下RGB2YUV422的汇编代码，如果是纯C代码在blackfin下运行，将耗费非常多的系统资源，汇编能大大缩短系统的转换时间-blackfin platform RGB2YUV422 assembly code, if it is pure C code running in the blackfin, will cost a lot of system resources, can greatly shorten the compilation time of conve