如何读取C ++中的硬编码地址的值？ [英] How to read a value of an hard coded address in C++?

问题描述

我正在寻找读取地址302H中的值。目的是从硬件（104pc堆栈的一部分）读取输入。当我运行下面的代码a得到这个错误：未处理的异常在0x004134b9在setOutput.exe：0xC0000005：访问冲突读取位置0x00000302

I am looking to read the value that is located in address 302H. The purpose is to read an input from hardware (a part of a 104pc stack). When I run the following code a get this error: Unhandled exception at 0x004134b9 in setOutput.exe: 0xC0000005: Access violation reading location 0x00000302.

#include <stdlib.h> 

#define PORTBASE 0x302
int _tmain(int argc, char *argv[])
{
    int value;
    int volatile * port = (int *) PORTBASE;
    printf("port = %d\n", port);
    value = *port;
    printf("port value = %d\n", value);
}

编辑：

我运行这下widows xp。只有文档我可以在板上找到

I am running this under widows xp. Only Documentation I can find on the board is below

编辑：

在下面的答案中，我可以看到我需要为板子编写驱动程序。

From your answers below, I can see that I need to write a driver for the board. Can someone point me to a resource on how to do so?

推荐答案

为了在Windows下直接访问物理内存，您需要开发驱动程序。我建议您阅读虚拟地址空间，了解原因。简短的故事：从用户模式进程看到的内存地址与物理内存地址无关，硬件生存的地址受操作系统保护，以防止用户模式应用程序弄乱事情。

In order to access physical memory directly under Windows, you need to develop a driver. I suggest you read up on Virtual Address Space to see why. The short story: The memory addresses you see from a usermode process has no relation to physical memory addresses, and the addresses where hardware lives are protected by the OS to prevent usermode applications from messing up things.

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