Very Computer

Is there any way to access memory directly?
I have to control a isa interface card which is memory mapped. Its
physical address is D0000h. I want to use GCC but I could not find any
proper function for this. Plese give me some comments.

--
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          ????1? ? ?t1

http://dfs.iis.u-tokyo.ac.jp/

   Institute of Industrial Science
        University of Tokyo
Hashimoto Lab. PhD Student Lee, Jooho

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--
Paul

|>

|>
|> > Is there any way to access memory directly?
|> > I have to control a isa interface card which is memory mapped. Its
|> > physical address is D0000h. I want to use GCC but I could not find any
|> > proper function for this. Plese give me some comments.
|>
|> Write a device driver.

And years later the driver works ;-) For this simple application, you can use the
mmap()-call to re-map physical memory into user-memory. You have to be root for
that, but shouldn't matter. An example:

void *map_mem(int phys_start)           /* call with 0xd0000 */
{
int fd;
void* log_start;

        fd = open("/dev/mem", O_RDWR);                /* maybe check error code... */
        log_start=mmap((caddr_t)0, 4096*2,      /* map 16K*/
                           PROT_READ|PROT_WRITE,
                           MAP_SHARED, fd,
                           (off_t)phys_start);
        close(fd);
        return log_start;

Quote:}

Please folks, just because you _can_ hit the hardware in Linux doesn't
make it a good idea.

--
     --Keith

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