The Unabridged Pentium 4 IA32 Processor Genealogy

Code Segment Descriptor Format

The value loaded into the visible part of CS (Figure 8-1) identifies:

• the descriptor table that contains the code segment descriptor.

  - TI = 0 indicates that the entry resides in the GDT.

  - TI = 1 indicates that the entry resides in the LDT.

• the entry in the specified descriptor table. The Index field identifies one of 8192d entries in the selected table.

The processor multiplies the index by eight (eight bytes per entry) to obtain the offset in the table. A check is performed to ensure that the offset is not beyond the indicated table's limit (supplied from the GDTR or LDTR register). Otherwise, an exception results. The offset is then added to the table base address (supplied from the GDTR or LDTR register) to form ...