#pragma once

#ifdef __cplusplus
extern "C"
{
#endif

FORCEINLINE
PKGDTENTRY
KiGetGdtEntry(
    _In_ PVOID pGdt,
    _In_ USHORT Selector)
{
    return (PKGDTENTRY)((ULONG_PTR)pGdt + (Selector & ~RPL_MASK));
}

FORCEINLINE
VOID
KiSetGdtDescriptorBase(
    _Inout_ PKGDTENTRY Entry,
    _In_ ULONG32 Base)
{
    Entry->BaseLow = (USHORT)(Base & 0xffff);
    Entry->HighWord.Bytes.BaseMid = (UCHAR)((Base >> 16) & 0xff);
    Entry->HighWord.Bytes.BaseHi  = (UCHAR)((Base >> 24) & 0xff);
    // Entry->BaseUpper = (ULONG)(Base >> 32);
}

FORCEINLINE
VOID
KiSetGdtDescriptorLimit(
    _Inout_ PKGDTENTRY Entry,
    _In_ ULONG Limit)
{
    if (Limit < 0x100000)
    {
        Entry->HighWord.Bits.Granularity = 0;
    }
    else
    {
        Limit >>= 12;
        Entry->HighWord.Bits.Granularity = 1;
    }
    Entry->LimitLow = (USHORT)(Limit & 0xffff);
    Entry->HighWord.Bits.LimitHi = ((Limit >> 16) & 0x0f);
}

FORCEINLINE
VOID
KiSetGdtEntryEx(
    _Inout_ PKGDTENTRY Entry,
    _In_ ULONG32 Base,
    _In_ ULONG Limit,
    _In_ UCHAR Type,
    _In_ UCHAR Dpl,
    _In_ BOOLEAN Granularity,
    _In_ UCHAR SegMode) // 0: 16-bit, 1: 32-bit, 2: 64-bit
{
    KiSetGdtDescriptorBase(Entry, Base);
    KiSetGdtDescriptorLimit(Entry, Limit);
    Entry->HighWord.Bits.Type = (Type & 0x1f);
    Entry->HighWord.Bits.Dpl  = (Dpl & 0x3);
    Entry->HighWord.Bits.Pres = (Type != 0); // Present, must be 1 when the GDT entry is valid.
    Entry->HighWord.Bits.Sys  = 0;           // System
    Entry->HighWord.Bits.Reserved_0  = 0;    // LongMode = !!(SegMode & 1);
    Entry->HighWord.Bits.Default_Big = !!(SegMode & 2);
    Entry->HighWord.Bits.Granularity |= !!Granularity; // The flag may have been already set by KiSetGdtDescriptorLimit().
    // Entry->MustBeZero = 0;
}

FORCEINLINE
VOID
KiSetGdtEntry(
    _Inout_ PKGDTENTRY Entry,
    _In_ ULONG32 Base,
    _In_ ULONG Limit,
    _In_ UCHAR Type,
    _In_ UCHAR Dpl,
    _In_ UCHAR SegMode) // 0: 16-bit, 1: 32-bit, 2: 64-bit
{
    KiSetGdtEntryEx(Entry, Base, Limit, Type, Dpl, FALSE, SegMode);
}

#if defined(__GNUC__)

FORCEINLINE
VOID
__lgdt(_Out_ PVOID Descriptor)
{
    PVOID* desc = (PVOID*)Descriptor;
    __asm__ __volatile__(
        "lgdt %0"
            : "=m" (*desc)
            : /* no input */
            : "memory");
}

FORCEINLINE
VOID
__sgdt(_Out_ PVOID Descriptor)
{
    PVOID* desc = (PVOID*)Descriptor;
    __asm__ __volatile__(
        "sgdt %0"
            : "=m" (*desc)
            : /* no input */
            : "memory");
}

FORCEINLINE
VOID
Ke386FxStore(IN PFX_SAVE_AREA SaveArea)
{
    asm volatile ("fxrstor (%0)" : : "r"(SaveArea));
}

FORCEINLINE
VOID
Ke386FxSave(IN PFX_SAVE_AREA SaveArea)
{
    asm volatile ("fxsave (%0)" : : "r"(SaveArea));
}

FORCEINLINE
VOID
Ke386FnSave(IN PFLOATING_SAVE_AREA SaveArea)
{
    asm volatile ("fnsave (%0); wait" : : "r"(SaveArea));
}

FORCEINLINE
VOID
Ke386SaveFpuState(IN PFX_SAVE_AREA SaveArea)
{
    extern ULONG KeI386FxsrPresent;
    if (KeI386FxsrPresent)
    {
        __asm__ __volatile__ ("fxsave %0\n" : : "m"(*SaveArea));
    }
    else
    {
        __asm__ __volatile__ ("fnsave %0\n wait\n" : : "m"(*SaveArea));
    }
}

FORCEINLINE
VOID
Ke386RestoreFpuState(_In_ PFX_SAVE_AREA SaveArea)
{
    extern ULONG KeI386FxsrPresent;
    if (KeI386FxsrPresent)
    {
        __asm__ __volatile__ ("fxrstor %0\n" : : "m"(*SaveArea));
    }
    else
    {
        __asm__ __volatile__ ("frstor %0\n\t" : "=m" (*SaveArea));
    }
}

FORCEINLINE
VOID
Ke386ClearFpExceptions(VOID)
{
    __asm__ __volatile__ ("fnclex");
}

FORCEINLINE
VOID
__sldt(PVOID Descriptor)
{
    __asm__ __volatile__(
        "sldt %0"
            : "=m" (*((short*)Descriptor))
            : /* no input */
            : "memory");
}

#define Ke386SetLocalDescriptorTable(X) \
    __asm__("lldt %w0\n\t" \
    : /* no outputs */ \
    : "q" (X));

#define Ke386SetTr(X)                   __asm__ __volatile__("ltr %%ax" : :"a" (X));

FORCEINLINE
USHORT
Ke386GetTr(VOID)
{
    USHORT Tr;
    __asm__("str %0\n\t"
    : "=m" (Tr));
    return Tr;
}

#define _Ke386GetSeg(N)           ({ \
                                     unsigned int __d; \
                                     __asm__("movl %%" #N ",%0\n\t" :"=r" (__d)); \
                                     __d; \
                                  })

#define _Ke386SetSeg(N,X)         __asm__ __volatile__("movl %0,%%" #N : :"r" (X));

#define Ke386FnInit()               __asm__("fninit\n\t");
#define Ke386ClearDirectionFlag()   __asm__ __volatile__ ("cld")


//
// CR Macros
//
#define Ke386SetCr2(X)              __asm__ __volatile__("movl %0,%%cr2" : :"r" (X));

//
// Segment Macros
//
#define Ke386GetSs()                _Ke386GetSeg(ss)
#define Ke386GetFs()                _Ke386GetSeg(fs)
#define Ke386GetDs()                _Ke386GetSeg(ds)
#define Ke386GetEs()                _Ke386GetSeg(es)
#define Ke386GetGs()                _Ke386GetSeg(gs)
#define Ke386SetFs(X)               _Ke386SetSeg(fs, X)
#define Ke386SetDs(X)               _Ke386SetSeg(ds, X)
#define Ke386SetEs(X)               _Ke386SetSeg(es, X)
#define Ke386SetSs(X)               _Ke386SetSeg(ss, X)
#define Ke386SetGs(X)               _Ke386SetSeg(gs, X)

#elif defined(_MSC_VER)

FORCEINLINE
VOID
Ke386FnInit(VOID)
{
    __asm fninit;
}

FORCEINLINE
VOID
__sgdt(OUT PVOID Descriptor)
{
    __asm
    {
        mov eax, Descriptor
        sgdt [eax]
    }
}

FORCEINLINE
VOID
__fxsave(OUT PFX_SAVE_AREA SaveArea)
{
    __asm mov eax, SaveArea
    __asm fxsave [eax]
}

FORCEINLINE
VOID
__fxrstor(IN PFX_SAVE_AREA SaveArea)
{
    __asm mov eax, SaveArea
    __asm fxrstor [eax]
}

FORCEINLINE
VOID
__frstor(_In_ PFX_SAVE_AREA SaveArea)
{
    __asm mov eax, SaveArea
    __asm frstor [eax]
}

FORCEINLINE
VOID
__fnsave(OUT PFLOATING_SAVE_AREA SaveArea)
{
    __asm mov eax, SaveArea
    __asm fnsave [eax]
    __asm wait;
}

FORCEINLINE
VOID
__lgdt(IN PVOID Descriptor)
{
    __asm
    {
        mov eax, Descriptor
        lgdt [eax]
    }
}

FORCEINLINE
VOID
__sldt(PVOID Descriptor)
{
    __asm
    {
        sldt ax
        mov ecx, Descriptor
        mov [ecx], ax
    }
}

FORCEINLINE
VOID
Ke386SetLocalDescriptorTable(IN USHORT Descriptor)
{
    __asm lldt Descriptor;
}

FORCEINLINE
VOID
Ke386SetTr(IN USHORT Tr)
{
    __asm ltr Tr;
}

FORCEINLINE
USHORT
Ke386GetTr(VOID)
{
    __asm str ax;
}

//
// CR Macros
//
FORCEINLINE
VOID
Ke386SetCr2(IN ULONG Value)
{
    __asm mov eax, Value;
    __asm mov cr2, eax;
}

//
// Segment Macros
//
FORCEINLINE
USHORT
Ke386GetSs(VOID)
{
    __asm mov ax, ss;
}

FORCEINLINE
USHORT
Ke386GetFs(VOID)
{
    __asm mov ax, fs;
}

FORCEINLINE
USHORT
Ke386GetDs(VOID)
{
    __asm mov ax, ds;
}

FORCEINLINE
USHORT
Ke386GetEs(VOID)
{
    __asm mov ax, es;
}

FORCEINLINE
VOID
Ke386SetSs(IN USHORT Value)
{
    __asm mov ax, Value;
    __asm mov ss, ax;
}

FORCEINLINE
VOID
Ke386SetFs(IN USHORT Value)
{
    __asm mov ax, Value;
    __asm mov fs, ax;
}

FORCEINLINE
VOID
Ke386SetDs(IN USHORT Value)
{
    __asm mov ax, Value;
    __asm mov ds, ax;
}

FORCEINLINE
VOID
Ke386SetEs(IN USHORT Value)
{
    __asm mov ax, Value;
    __asm mov es, ax;
}

FORCEINLINE
VOID
Ke386SetGs(IN USHORT Value)
{
    __asm mov ax, Value;
    __asm mov gs, ax;
}

extern ULONG KeI386FxsrPresent;

FORCEINLINE
VOID
Ke386SaveFpuState(IN PVOID SaveArea)
{
    if (KeI386FxsrPresent)
    {
        __fxsave((PFX_SAVE_AREA)SaveArea);
    }
    else
    {
        __fnsave((PFLOATING_SAVE_AREA)SaveArea);
    }
}

FORCEINLINE
VOID
Ke386RestoreFpuState(_In_ PVOID SaveArea)
{
    if (KeI386FxsrPresent)
    {
        __fxrstor((PFX_SAVE_AREA)SaveArea);
    }
    else
    {
        __frstor((PFX_SAVE_AREA)SaveArea);
    }
}

FORCEINLINE
VOID
Ke386ClearFpExceptions(VOID)
{
    __asm fnclex;
}

#define Ke386FnSave __fnsave
#define Ke386FxSave __fxsave
// The name suggest, that the original author didn't understand what frstor means
#define Ke386FxStore __fxrstor

#else
#error Unknown compiler for inline assembler
#endif

#define Ke386GetGlobalDescriptorTable __sgdt
#define Ke386SetGlobalDescriptorTable __lgdt
#define Ke386GetLocalDescriptorTable __sldt

#ifdef __cplusplus
} // extern "C"
#endif

/* EOF */