Compute Literal Address from Segmented Address

Question

For example, say I have something like:

    0x33:0x10

and I want to get an address in the form:

    0x????????

from it. What is the easiest way to go about doing this? This is on Linux x86.

Answer 1

The selector in the segment register is decoded to give a descriptor table specifier and a descriptor table index. The base given in the table and index is added to the offset in order to give a final address within process space. In order to convert process memory to physical memory, the page tables must be read and decoded.