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Segmentation: Difference between revisions
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==Protected Mode==
:''Read more about [[Global Descriptor Table]] or [[GDT for dummies]].''
In [[Protected Mode]] you use a logical address in the form A:B to address memory. As in [[Real Mode]], A is the segment part and B is the offset within that segment. The registers in protected mode are limited to 32 bits. 32 bits can represent any integer between 0 and 4Gb.
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Now for the difference.
In protected mode A is not an absolute value for the segment. In protected mode A is a selector. A selector represents an offset into a system table called the [[Global Descriptor Table]] (GDT). The GDT contains a list of descriptors. Each of these descriptors contains information that describes the characteristics of a segment.
Each segment descriptor contains the following information:
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In protected mode CS can also be changed via the TSS or a gate.
==Notes Regarding C==
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