1 临时变量或非直接页内存的全局变量经常不起作用，赋值赋不进,换成zero_ram区的全局变量就OK了； 2 临时变量或非直接页内存的全局变量容易引起程序出错,换成zero_ram区的全局变量就OK了； 3 有浮点运算时出错率大增； 4 有中断函数时出错率增加；   如： 程序写法一：（会出错，Table_test算出的常是完全不对的值;或者每次算出的值不一样，会有微小跳动） void Cal_Test(float *Table_test)                                                                    
{                                                                                       
        unsigned char i=0;          for(i=0;i<100;i++)         {                  Table_test+=0.0045*i+123.456;         }                                                                      
}                                                                               
程序写法二：（会出错，Table_test算出的常是完全不对的值;或者每次算出的值不一样，会有微小跳动） #pragma DATA_SEG DEFAULT volatile unsigned char i=0;  void Cal_Test(float *Table_test)                                                                    
{                                                                                       
        for(i=0;i<100;i++)         {                  Table_test+=0.0045*i+123.456;         }                                                                      
}  程序写法三：（能得到正确结果） #pragma DATA_SEG __SHORT_SEG MY_ZEROPAGE     //开始 0 页数据定义
volatile unsigned char i=0;  void Cal_Test(float *Table_test)                                                                    
{                                                                                       
        for(i=0;i<100;i++)         {                  Table_test+=0.0045*i+123.456;         }                                                                      
}                                                                                
单片机：mc9s08qe4/8 编译环境：freescale codewarrior v6.2 试用版(破解版) 不知各位有没出现类似情况，这是MCU就这水平，还是编译器设置问题，还是编译器有问题？ 1 此帖出自小平头技术问答