指向特定固定地址的指针 [英] Pointer to a specific fixed address

问题描述

如何为指针分配特定的内存地址?

How do you assign a specific memory address to a pointer?

AVR m128 等微控制器中的特殊功能寄存器有固定地址，AVR GCC 在 io.h 头文件中定义了 SFR，但我想自己处理.

The Special Function Registers in a microcontroller such AVR m128 has fixed addresses, the AVR GCC defines the SFR in the io.h header file, but I want to handle it myself.

推荐答案

好的，没问题.你可以直接将它分配给一个变量:

Sure, no problem. You can just assign it directly to a variable:

volatile unsigned int *myPointer = (volatile unsigned int *)0x12345678;

我通常做的是声明一个内存映射 I/O 宏:

What I usually do is declare a memory-mapped I/O macro:

#define mmio32(x)   (*(volatile unsigned long *)(x))

然后在头文件中定义我的寄存器:

And then define my registers in a header file:

#define SFR_BASE    (0xCF800000)
#define SFR_1       (SFR_BASE + 0x0004)
#define SFR_2       (SFR_BASE + 0x0010)

然后使用它们:

unsigned long registerValue = mmio32(SFR_1); // read
mmio32(SFR2) = 0x85748312;                   // write

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