Zygoma::ia32::Descriptor Class Reference

#include <descriptor.h>

List of all members.

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Detailed Description

A segment descriptor is a data structure in a GDT or LDT that provides the processor with the size, location, type, and access control, and status of a memory segment.

Public Types
enum	Type {   kTYPE_RESERVED_0 = 0,   kTYPE_TSS_AVAILABLE = 1,   kTYPE_LDT = 2,   kTYPE_TSS_BUSY = 3,   kTYPE_CALL_GATE = 4,   kTYPE_TASK_GATE = 5,   kTYPE_INT_GATE = 6,   kTYPE_TRAP_GATE = 7 }
	The types defined for a system descriptor. More...
enum	Granularity {   kGRANULARITY_BYTE = 0,   kGRANULARITY_4K = 1 }
	Values indicating the granularity of the descriptor. More...
enum	OperationSize {   kOP_SIZE_16 = 0,   kOP_SIZE_32 = 1 }
	Values indicating the operation size of the descriptor. More...
Public Member Functions
Type	type () const
	Gets the type of the descriptor using a crude form of RTTI.
bool	isSystemDescriptor () const
	Returns true if this is a system descriptor, false if it's a memory (code or data) descriptor.
int	privilegeLevel () const
	Returns the privilege level (an integer ranging from 0 to 3) required to execute any code in this descriptor.
u32	base () const
	Gets the segment base address.
u32	limit () const
	Gets the segment size.
Granularity	granularity () const
	Gets the granularity.
OperationSize	operationSize () const
	Gets the default operation size of the desciptor.
bool	isPresent () const
	Indicates presence of the segment.
int	limit () const
Protected Attributes
u16	m_limit00_15
u16	m_base00_15
u08	m_base16_23
TypeUnion	m_flags1
u08	m_segmentLimit:4
u08	m_useMe:1
u08	m_reserved:1
u08	m_operationSize:1
u08	m_granularity:1
u08	m_base24_31
Classes
struct	CodeSegment
struct	DataSegment
struct	SystemSegment
union	TypeUnion

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Member Enumeration Documentation

enum Zygoma::ia32::Descriptor::Granularity

Values indicating the granularity of the descriptor. Enumeration values: kGRANULARITY_BYTE  Descriptor addresses 1 byte chunks. kGRANULARITY_4K  Descriptor addresses 4k chunks.

enum Zygoma::ia32::Descriptor::OperationSize

Values indicating the operation size of the descriptor. Enumeration values: kOP_SIZE_16  kOP_SIZE_32

enum Zygoma::ia32::Descriptor::Type

The types defined for a system descriptor. Enumeration values: kTYPE_RESERVED_0  kTYPE_TSS_AVAILABLE  kTYPE_LDT  kTYPE_TSS_BUSY  kTYPE_CALL_GATE  kTYPE_TASK_GATE  kTYPE_INT_GATE  kTYPE_TRAP_GATE

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Member Function Documentation

u32 Zygoma::ia32::Descriptor::base (   )  const [inline]

Gets the segment base address. The segment base address is the location of byte 0 in the memory segment described by this descriptor. The segment base address should be aligned on a 16-byte boundary. Returns: the logical base address of the segment.

Granularity Zygoma::ia32::Descriptor::granularity (   )  const [inline]

Gets the granularity. Granularity is either 1 byte or 0x1000 byte chunks.

bool Zygoma::ia32::Descriptor::isPresent (   )  const [inline]

Indicates presence of the segment. Returns: true of this segment is present, false otherwise.

bool Zygoma::ia32::Descriptor::isSystemDescriptor (   )  const [inline]

Returns true if this is a system descriptor, false if it's a memory (code or data) descriptor.

int Zygoma::ia32::Descriptor::limit (   )  const [inline]

u32 Zygoma::ia32::Descriptor::limit (   )  const [inline]

Gets the segment size. If the granularity flag is true, this value indicates 4 kilobyte increments and the segment can address up to 4 GB, otherwise it measures in byte increments and the segment can address up to 1 MB. Returns: the segment size in chunks (the size of a chunk depends on the granularity setting of te descriptor).

OperationSize Zygoma::ia32::Descriptor::operationSize (   )  const [inline]

Gets the default operation size of the desciptor. Returns: the default operation size (16-bit or 32-bit).

int Zygoma::ia32::Descriptor::privilegeLevel (   )  const [inline]

Returns the privilege level (an integer ranging from 0 to 3) required to execute any code in this descriptor.

Type Zygoma::ia32::Descriptor::type (   )  const [inline]

Gets the type of the descriptor using a crude form of RTTI. Returns: the Type of the descriptor.

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Member Data Documentation

u16 Zygoma::ia32::Descriptor::m_base00_15 [protected]

u08 Zygoma::ia32::Descriptor::m_base16_23 [protected]

u08 Zygoma::ia32::Descriptor::m_base24_31 [protected]

TypeUnion Zygoma::ia32::Descriptor::m_flags1 [protected]

u08 Zygoma::ia32::Descriptor::m_granularity [protected]

u16 Zygoma::ia32::Descriptor::m_limit00_15 [protected]

u08 Zygoma::ia32::Descriptor::m_operationSize [protected]

u08 Zygoma::ia32::Descriptor::m_reserved [protected]

u08 Zygoma::ia32::Descriptor::m_segmentLimit [protected]

u08 Zygoma::ia32::Descriptor::m_useMe [protected]

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The documentation for this class was generated from the following file:

• descriptor.h

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