Descriptor Cache: Difference between revisions

The cache for each segment selector (CS, SS, DS, ES, FS, GS) contains all of the bits and fields you would also find in the [[GDT]]. These include descriptor type, access rights, base and limit. In [[Protected Mode|protected mode]] these fields are filled from the GDT or LDT whenever there is data written to a segment selector (both implicitly and explicitly). In real mode, the processor generates entries internally as there is no GDT involved in this mode. Interestingly, not all fields are updated in real mode. Most notably that includes the segment limit.