paging problems

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northfuse

paging problems

Post 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!
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Brendan
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Re:paging problems

Post 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
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Pype.Clicker
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Re:paging problems

Post by Pype.Clicker »

might you have shifted your physical address once too much ?
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