F28M35 系统初始化部分程序的理解

您好！我在学习controlsuit中F28m35的Dual system Example的Blinky的例子。在M3中有下面两句程序：

#ifdef _FLASH                         
// Copy time critical code and Flash setup code to RAM
// This includes the following functions:  InitFlash();
// The  RamfuncsLoadStart, RamfuncsLoadSize, and RamfuncsRunStart
// symbols are created by the linker. Refer to the device .cmd file.
    memcpy(&RamfuncsRunStart, &RamfuncsLoadStart, (size_t)&RamfuncsLoadSize);     
// Call Flash Initialization to setup flash waitstates
// This function must reside in RAM
    FlashInit();    

我想请教下它用来干嘛的，是否是必须的（有些例子中并未使用这两条语句）？