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#define _IO_ADDRESS(r) ((r)+0xf0000000) unsigned int READREG(unsigned int r) { volatile unsigned int * reg; reg = (volatile unsigned int*) _IO_ADDRESS(r); return *reg; } void WRITEREG(unsigned int r, unsigned int val) { volatile unsigned int *reg; reg = (volatile unsigned int*) _IO_ADDRESS(r); *reg = val; return; } 中是针对MX1关于LCD的一段代码，其中的#define _IO_ADDRESS(r) ((r)+0xf0000000) 为什么要加0XF0000000不加的话才对啊！