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java.lang.Objectnachos.machine.SegmentDescriptor
public final class SegmentDescriptor
This class defines an entry in a segment table. Each entry contains base and size registers, which define a mapping from a range of virtual addresses to a range of physical addresses. In addition, there are some extra bits for access control (valid and read-only). A certain number of the most-significant bits of the virtual address are used as the segment selector, depending on the configured size of the segment table (which must be a power of two). The remaining bits are used as the offset within the selected segment.
Field Summary | |
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long |
base
The base address of the segment in physical memory. |
boolean |
readOnly
If this bit is set, the user program is not allowed to modify the contents of the segment. |
long |
size
The size of the segment in bytes. |
boolean |
valid
If this bit is not set, the segment is ignored. |
Constructor Summary | |
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SegmentDescriptor()
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Method Summary |
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Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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public long base
public long size
public boolean valid
public boolean readOnly
Constructor Detail |
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public SegmentDescriptor()
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