原创 IAR中const 处理

以下结论是实测得出的：
如果定义在函数内部，则占用RAM空间:0x200005f4
如果定义为全局变量则占rom空间。0x80064e4
帮助中“IAR C/C++ Development Guide”
描述如下：
DECLARING OBJECTS CONST
The const type qualifier is used for indicating that a data object, accessed directly or
via a pointer, is non-writable. A pointer to const declared data can point to both
constant and non-constant objects. It is good programming practice to use const
declared pointers whenever possible because this improves the compiler’s possibilities
to optimize the generated code and reduces the risk of application failure due to
erroneously modified data.
Static and global objects declared const are allocated in ROM.
In C++, objects that require runtime initialization cannot be placed in ROM.
也就是说如果定义在函数内部的话，需要加上static