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paging problems
Posted: Sun Jun 20, 2004 8:42 pm
by northfuse
okay, paging is up and working. Invaild page addresses trigger a pagefault, but i'm unable to access mapped memory! I map a virtual address to a physical address, mark it as rw and present, and write to it. But, when I read it, it says that it equals '-1' no matter what. please help!
Re:paging problems
Posted: Mon Jun 21, 2004 12:19 am
by Brendan
Hi,
northfuse wrote:
okay, paging is up and working. Invaild page addresses trigger a pagefault, but i'm unable to access mapped memory! I map a virtual address to a physical address, mark it as rw and present, and write to it. But, when I read it, it says that it equals '-1' no matter what. please help!
This sounds like you've put the wrong physical addresses into the page table entries. For e.g. if you tell the CPU to read from physical address 0xC0000000 and there isn't that much memory present it can read 0xFFFFFFFF (especially under Bochs, real computer can be more complex).
Cheers,
Brendan
Re:paging problems
Posted: Mon Jun 21, 2004 4:30 am
by Pype.Clicker
might you have shifted your physical address once too much ?