Saturday, October 30, 2010

Virtual Memory

So we were asked to devise a way to figure out which page a particular physical address was in, as well as it's offset.

Turns out this is a really simple problem, in this case each page is 4kb, which really means 4096 bytes, so simply take the address, divide by that 4096 bytes, and that tells you which page it's in. From there you subtract the number of bytes of the previous pages (4096 * n)  from the address and you get the offset.

So the nice thing about virtual memory, is that you basically always know your address will reside within a 4096 byte address. This can make more static stuff easier to handle, rather then trying to guess which physical address you are, then figure out some kind of offset.

Here is the program I wrote in action.

Well I hope you enjoyed, I know it was a bit short, but the problem was really easy to see a solution, if you're having problems understanding how to find a page and offset, please let me know and I'll do my best to help!