Segment selectors
The kernel maintains a table to translate selector values to segment base paragraphs.
The kernel maintains a table to translate selector values to segment base paragraphs.
A Paragraph is a 16byte quantity. This table and translation is necessary because IBM PC uses 16bit selectors in instructions but segments may reside anywhere in the linear addressing space. For example, if a segment with selector 5 resides at 0x400000, we need to have selector translation 5 -> 0x400000. For 16bit programs the selector translation table is usually empty, selector values are equal to segment base paragraphs.
Generated by