Introduction - If you have any usage issues, please Google them yourself
Necessary to optimize the level of s, other optimization levels will not lead to compile-time error, but it will result in run-time error. Reasons relating to the allocation of local variables, stack processing in different ways, that is, OS_CPU_A.c that the transplanted parts of the file. There are other optimization related to the interruption of the number of registers saved automatically have access to.