crashpad::CPUContextX86 Struct Reference

A context structure carrying 32-bit x86 CPU state. More...

#include "snapshot/cpu_context.h"

Classes
struct	Fsave
struct	Fxsave
union	X87OrMMXRegister

Public Types
using	X87Register = uint8_t[10]
using	XMMRegister = uint8_t[16]

Static Public Member Functions
static void	FxsaveToFsave (const Fxsave &fxsave, Fsave *fsave)
	Converts an fxsave area to an fsave area. More...
static void	FsaveToFxsave (const Fsave &fsave, Fxsave *fxsave)
	Converts an fsave area to an fxsave area. More...
static uint16_t	FxsaveToFsaveTagWord (uint16_t fsw, uint8_t fxsave_tag, const X87OrMMXRegister st_mm[8])
	Converts x87 floating-point tag words from fxsave (abridged, 8-bit) to fsave (full, 16-bit) form. More...
static uint8_t	FsaveToFxsaveTagWord (uint16_t fsave_tag)
	Converts x87 floating-point tag words from fsave (full, 16-bit) to fxsave (abridged, 8-bit) form. More...

Public Attributes
uint32_t	eax
uint32_t	ebx
uint32_t	ecx
uint32_t	edx
uint32_t	edi
uint32_t	esi
uint32_t	ebp
uint32_t	esp
uint32_t	eip
uint32_t	eflags
uint16_t	cs
uint16_t	ds
uint16_t	es
uint16_t	fs
uint16_t	gs
uint16_t	ss
Fxsave	fxsave
uint32_t	dr0
uint32_t	dr1
uint32_t	dr2
uint32_t	dr3
uint32_t	dr4
uint32_t	dr5
uint32_t	dr6
uint32_t	dr7

Detailed Description

A context structure carrying 32-bit x86 CPU state.

Member Function Documentation

FsaveToFxsave()

void crashpad::CPUContextX86::FsaveToFxsave ( const Fsave &  fsave, Fxsave *  fxsave  )

static

Converts an fsave area to an fxsave area.

fsave state is restricted to the x87 FPU, while fxsave state includes state related to the x87 FPU as well as state specific to SSE.

As the fsave format is a subset of the fxsave format, this operation cannot fully populate the fxsave area. Fields in fxsave that have no equivalent in fsave are set to 0, including Fxsave::mxcsr, Fxsave::mxcsr_mask, Fxsave::xmm, and Fxsave::available. FsaveToFxsaveTagWord() is used to derive Fxsave::ftw from the full 16-bit form used by fsave. Reserved fields in fxsave are set to 0.

Parameters

[in]	fsave	The fsave area to convert.
[out]	fxsave	The fxsave area to populate.

See also

FxsaveToFsave()

FsaveToFxsaveTagWord()

uint8_t crashpad::CPUContextX86::FsaveToFxsaveTagWord ( uint16_t  fsave_tag )

static

Converts x87 floating-point tag words from fsave (full, 16-bit) to fxsave (abridged, 8-bit) form.

This function performs the inverse operation of FxsaveToFsaveTagWord().

Parameters

[in]

fsave_tag

The full FPU tag word.

Returns

The abridged FPU tag word.

FxsaveToFsave()

void crashpad::CPUContextX86::FxsaveToFsave ( const Fxsave &  fxsave, Fsave *  fsave  )

static

Converts an fxsave area to an fsave area.

fsave state is restricted to the x87 FPU, while fxsave state includes state related to the x87 FPU as well as state specific to SSE.

As the fxsave format is a superset of the fsave format, this operation fully populates the fsave area. fsave uses the full 16-bit form for the x87 floating-point tag word, so FxsaveToFsaveTagWord() is used to derive Fsave::ftw from the abridged 8-bit form used by fxsave. Reserved fields in fsave are set to 0.

Parameters

[in]	fxsave	The fxsave area to convert.
[out]	fsave	The fsave area to populate.

See also

FsaveToFxsave()

FxsaveToFsaveTagWord()

uint16_t crashpad::CPUContextX86::FxsaveToFsaveTagWord ( uint16_t  fsw, uint8_t  fxsave_tag, const X87OrMMXRegister  st_mm[8]  )

static

Converts x87 floating-point tag words from fxsave (abridged, 8-bit) to fsave (full, 16-bit) form.

fxsave stores the x87 floating-point tag word in abridged 8-bit form, and fsave stores it in full 16-bit form. Some users, notably CPUContextX86::Fsave::ftw, require the full 16-bit form, where most other contemporary code uses fxsave and thus the abridged 8-bit form found in CPUContextX86::Fxsave::ftw.

This function converts an abridged tag word to the full version by using the abridged tag word and the contents of the registers it describes. See Intel Software Developer’s Manual, Volume 2A: Instruction Set Reference A-M (253666-052), 3.2 “FXSAVE”, specifically, the notes on the abridged FTW and recreating the FSAVE format, and AMD Architecture Programmer’s Manual, Volume 2: System Programming (24593-3.24), “FXSAVE Format for x87 Tag Word”.

See also

FsaveToFxsaveTagWord()

Parameters

[in]	fsw	The FPU status word, used to map logical st_mm registers to their physical counterparts. This can be taken from CPUContextX86::Fxsave::fsw.
[in]	fxsave_tag	The abridged FPU tag word. This can be taken from CPUContextX86::Fxsave::ftw.
[in]	st_mm	The floating-point registers in logical order. This can be taken from CPUContextX86::Fxsave::st_mm.

Returns

The full FPU tag word.

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The documentation for this struct was generated from the following files:

• snapshot/cpu_context.h
• snapshot/cpu_context.cc