reactos/lib/soft386/common.inl
Aleksandar Andrejevic 17a32f3b2a [SOFT386]
Change the license of Soft386 to GPLv2. The previous license was also
GPLv2, but it had a runtime linking exception. The new license is the
original GPLv2 with no exceptions.


svn path=/branches/ntvdm/; revision=60485
2013-09-30 22:01:38 +00:00

971 lines
27 KiB
C++

/*
* Soft386 386/486 CPU Emulation Library
* common.inl
*
* Copyright (C) 2013 Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/* PUBLIC FUNCTIONS ***********************************************************/
FORCEINLINE
VOID
Soft386Exception(PSOFT386_STATE State,
SOFT386_EXCEPTIONS ExceptionCode)
{
/* Call the internal function */
Soft386ExceptionWithErrorCode(State, ExceptionCode, 0);
}
FORCEINLINE
BOOLEAN
Soft386StackPush(PSOFT386_STATE State,
ULONG Value)
{
BOOLEAN Size = State->SegmentRegs[SOFT386_REG_SS].Size;
/* The OPSIZE prefix toggles the size */
if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE) Size = !Size;
if (Size)
{
/* 32-bit size */
/* Check if ESP is between 1 and 3 */
if (State->GeneralRegs[SOFT386_REG_ESP].Long >= 1
&& State->GeneralRegs[SOFT386_REG_ESP].Long <= 3)
{
Soft386Exception(State, SOFT386_EXCEPTION_SS);
return FALSE;
}
/* Subtract ESP by 4 */
State->GeneralRegs[SOFT386_REG_ESP].Long -= 4;
/* Store the value in SS:ESP */
return Soft386WriteMemory(State,
SOFT386_REG_SS,
State->GeneralRegs[SOFT386_REG_ESP].Long,
&Value,
sizeof(ULONG));
}
else
{
/* 16-bit size */
USHORT ShortValue = LOWORD(Value);
/* Check if SP is 1 */
if (State->GeneralRegs[SOFT386_REG_ESP].Long == 1)
{
Soft386Exception(State, SOFT386_EXCEPTION_SS);
return FALSE;
}
/* Subtract SP by 2 */
State->GeneralRegs[SOFT386_REG_ESP].LowWord -= 2;
/* Store the value in SS:SP */
return Soft386WriteMemory(State,
SOFT386_REG_SS,
State->GeneralRegs[SOFT386_REG_ESP].LowWord,
&ShortValue,
sizeof(USHORT));
}
}
FORCEINLINE
BOOLEAN
Soft386StackPop(PSOFT386_STATE State,
PULONG Value)
{
ULONG LongValue;
USHORT ShortValue;
BOOLEAN Size = State->SegmentRegs[SOFT386_REG_SS].Size;
/* The OPSIZE prefix toggles the size */
if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE) Size = !Size;
if (Size)
{
/* 32-bit size */
/* Check if ESP is 0xFFFFFFFF */
if (State->GeneralRegs[SOFT386_REG_ESP].Long == 0xFFFFFFFF)
{
Soft386Exception(State, SOFT386_EXCEPTION_SS);
return FALSE;
}
/* Read the value from SS:ESP */
if (!Soft386ReadMemory(State,
SOFT386_REG_SS,
State->GeneralRegs[SOFT386_REG_ESP].Long,
FALSE,
&LongValue,
sizeof(LongValue)))
{
/* An exception occurred */
return FALSE;
}
/* Increment ESP by 4 */
State->GeneralRegs[SOFT386_REG_ESP].Long += 4;
/* Store the value in the result */
*Value = LongValue;
}
else
{
/* 16-bit size */
/* Check if SP is 0xFFFF */
if (State->GeneralRegs[SOFT386_REG_ESP].LowWord == 0xFFFF)
{
Soft386Exception(State, SOFT386_EXCEPTION_SS);
return FALSE;
}
/* Read the value from SS:SP */
if (!Soft386ReadMemory(State,
SOFT386_REG_SS,
State->GeneralRegs[SOFT386_REG_ESP].LowWord,
FALSE,
&ShortValue,
sizeof(ShortValue)))
{
/* An exception occurred */
return FALSE;
}
/* Increment SP by 2 */
State->GeneralRegs[SOFT386_REG_ESP].Long += 2;
/* Store the value in the result */
*Value = ShortValue;
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386LoadSegment(PSOFT386_STATE State,
INT Segment,
USHORT Selector)
{
PSOFT386_SEG_REG CachedDescriptor;
SOFT386_GDT_ENTRY GdtEntry;
ASSERT(Segment < SOFT386_NUM_SEG_REGS);
/* Get the cached descriptor */
CachedDescriptor = &State->SegmentRegs[Segment];
/* Check for protected mode */
if ((State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE) && !State->Flags.Vm)
{
/* Make sure the GDT contains the entry */
if (GET_SEGMENT_INDEX(Selector) >= (State->Gdtr.Size + 1))
{
Soft386Exception(State, SOFT386_EXCEPTION_GP);
return FALSE;
}
/* Read the GDT */
// FIXME: This code is only correct when paging is disabled!!!
if (State->MemReadCallback)
{
State->MemReadCallback(State,
State->Gdtr.Address
+ GET_SEGMENT_INDEX(Selector),
&GdtEntry,
sizeof(GdtEntry));
}
else
{
RtlMoveMemory(&GdtEntry,
(PVOID)(State->Gdtr.Address
+ GET_SEGMENT_INDEX(Selector)),
sizeof(GdtEntry));
}
/* Check if we are loading SS */
if (Segment == SOFT386_REG_SS)
{
if (GET_SEGMENT_INDEX(Selector) == 0)
{
Soft386Exception(State, SOFT386_EXCEPTION_GP);
return FALSE;
}
if (GdtEntry.Executable || !GdtEntry.ReadWrite)
{
Soft386Exception(State, SOFT386_EXCEPTION_GP);
return FALSE;
}
if ((GET_SEGMENT_RPL(Selector) != Soft386GetCurrentPrivLevel(State))
|| (GET_SEGMENT_RPL(Selector) != GdtEntry.Dpl))
{
Soft386Exception(State, SOFT386_EXCEPTION_GP);
return FALSE;
}
if (!GdtEntry.Present)
{
Soft386Exception(State, SOFT386_EXCEPTION_SS);
return FALSE;
}
}
else
{
if ((GET_SEGMENT_RPL(Selector) > GdtEntry.Dpl)
&& (Soft386GetCurrentPrivLevel(State) > GdtEntry.Dpl))
{
Soft386Exception(State, SOFT386_EXCEPTION_GP);
return FALSE;
}
if (!GdtEntry.Present)
{
Soft386Exception(State, SOFT386_EXCEPTION_NP);
return FALSE;
}
}
/* Update the cache entry */
CachedDescriptor->Selector = Selector;
CachedDescriptor->Base = GdtEntry.Base | (GdtEntry.BaseHigh << 24);
CachedDescriptor->Limit = GdtEntry.Limit | (GdtEntry.LimitHigh << 16);
CachedDescriptor->Accessed = GdtEntry.Accessed;
CachedDescriptor->ReadWrite = GdtEntry.ReadWrite;
CachedDescriptor->DirConf = GdtEntry.DirConf;
CachedDescriptor->Executable = GdtEntry.Executable;
CachedDescriptor->SystemType = GdtEntry.SystemType;
CachedDescriptor->Dpl = GdtEntry.Dpl;
CachedDescriptor->Present = GdtEntry.Present;
CachedDescriptor->Size = GdtEntry.Size;
/* Check for page granularity */
if (GdtEntry.Granularity) CachedDescriptor->Limit <<= 12;
}
else
{
/* Update the selector and base */
CachedDescriptor->Selector = Selector;
CachedDescriptor->Base = Selector << 4;
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386FetchByte(PSOFT386_STATE State,
PUCHAR Data)
{
PSOFT386_SEG_REG CachedDescriptor;
/* Get the cached descriptor of CS */
CachedDescriptor = &State->SegmentRegs[SOFT386_REG_CS];
/* Read from memory */
if (!Soft386ReadMemory(State,
SOFT386_REG_CS,
(CachedDescriptor->Size) ? State->InstPtr.Long
: State->InstPtr.LowWord,
TRUE,
Data,
sizeof(UCHAR)))
{
/* Exception occurred during instruction fetch */
return FALSE;
}
/* Advance the instruction pointer */
if (CachedDescriptor->Size) State->InstPtr.Long++;
else State->InstPtr.LowWord++;
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386FetchWord(PSOFT386_STATE State,
PUSHORT Data)
{
PSOFT386_SEG_REG CachedDescriptor;
/* Get the cached descriptor of CS */
CachedDescriptor = &State->SegmentRegs[SOFT386_REG_CS];
/* Read from memory */
// FIXME: Fix byte order on big-endian machines
if (!Soft386ReadMemory(State,
SOFT386_REG_CS,
(CachedDescriptor->Size) ? State->InstPtr.Long
: State->InstPtr.LowWord,
TRUE,
Data,
sizeof(USHORT)))
{
/* Exception occurred during instruction fetch */
return FALSE;
}
/* Advance the instruction pointer */
if (CachedDescriptor->Size) State->InstPtr.Long += sizeof(USHORT);
else State->InstPtr.LowWord += sizeof(USHORT);
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386FetchDword(PSOFT386_STATE State,
PULONG Data)
{
PSOFT386_SEG_REG CachedDescriptor;
/* Get the cached descriptor of CS */
CachedDescriptor = &State->SegmentRegs[SOFT386_REG_CS];
/* Read from memory */
// FIXME: Fix byte order on big-endian machines
if (!Soft386ReadMemory(State,
SOFT386_REG_CS,
(CachedDescriptor->Size) ? State->InstPtr.Long
: State->InstPtr.LowWord,
TRUE,
Data,
sizeof(ULONG)))
{
/* Exception occurred during instruction fetch */
return FALSE;
}
/* Advance the instruction pointer */
if (CachedDescriptor->Size) State->InstPtr.Long += sizeof(ULONG);
else State->InstPtr.LowWord += sizeof(ULONG);
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386GetIntVector(PSOFT386_STATE State,
UCHAR Number,
PSOFT386_IDT_ENTRY IdtEntry)
{
ULONG FarPointer;
/* Check for protected mode */
if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
{
/* Read from the IDT */
// FIXME: This code is only correct when paging is disabled!!!
if (State->MemReadCallback)
{
State->MemReadCallback(State,
State->Idtr.Address
+ Number * sizeof(*IdtEntry),
IdtEntry,
sizeof(*IdtEntry));
}
else
{
RtlMoveMemory(IdtEntry,
(PVOID)(State->Idtr.Address
+ Number * sizeof(*IdtEntry)),
sizeof(*IdtEntry));
}
}
else
{
/* Read from the real-mode IVT */
/* Paging is always disabled in real mode */
if (State->MemReadCallback)
{
State->MemReadCallback(State,
State->Idtr.Address
+ Number * sizeof(FarPointer),
&FarPointer,
sizeof(FarPointer));
}
else
{
RtlMoveMemory(IdtEntry,
(PVOID)(State->Idtr.Address
+ Number * sizeof(FarPointer)),
sizeof(FarPointer));
}
/* Fill a fake IDT entry */
IdtEntry->Offset = LOWORD(FarPointer);
IdtEntry->Selector = HIWORD(FarPointer);
IdtEntry->Zero = 0;
IdtEntry->Type = SOFT386_IDT_INT_GATE;
IdtEntry->Storage = FALSE;
IdtEntry->Dpl = 0;
IdtEntry->Present = TRUE;
IdtEntry->OffsetHigh = 0;
}
/*
* Once paging support is implemented this function
* will not always return true
*/
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386CalculateParity(UCHAR Number)
{
Number ^= Number >> 1;
Number ^= Number >> 2;
Number ^= Number >> 4;
return !(Number & 1);
}
FORCEINLINE
BOOLEAN
Soft386ParseModRegRm(PSOFT386_STATE State,
BOOLEAN AddressSize,
PSOFT386_MOD_REG_RM ModRegRm)
{
UCHAR ModRmByte, Mode, RegMem;
/* Fetch the MOD REG R/M byte */
if (!Soft386FetchByte(State, &ModRmByte))
{
/* Exception occurred */
return FALSE;
}
/* Unpack the mode and R/M */
Mode = ModRmByte >> 6;
RegMem = ModRmByte & 0x07;
/* Set the register operand */
ModRegRm->Register = (ModRmByte >> 3) & 0x07;
/* Check the mode */
if ((ModRmByte >> 6) == 3)
{
/* The second operand is also a register */
ModRegRm->Memory = FALSE;
ModRegRm->SecondRegister = RegMem;
/* Done parsing */
return TRUE;
}
/* The second operand is memory */
ModRegRm->Memory = TRUE;
if (AddressSize)
{
if (RegMem == SOFT386_REG_ESP)
{
UCHAR SibByte;
ULONG Scale, Index, Base;
/* Fetch the SIB byte */
if (!Soft386FetchByte(State, &SibByte))
{
/* Exception occurred */
return FALSE;
}
/* Unpack the scale, index and base */
Scale = 1 << (SibByte >> 6);
Index = (SibByte >> 3) & 0x07;
if (Index != SOFT386_REG_ESP) Index = State->GeneralRegs[Index].Long;
else Index = 0;
Base = State->GeneralRegs[SibByte & 0x07].Long;
/* Calculate the address */
ModRegRm->MemoryAddress = Base + Index * Scale;
}
else if (RegMem == SOFT386_REG_EBP)
{
if (Mode) ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBP].Long;
else ModRegRm->MemoryAddress = 0;
}
else
{
/* Get the base from the register */
ModRegRm->MemoryAddress = State->GeneralRegs[RegMem].Long;
}
/* Check if there is no segment override */
if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
{
/* Check if the default segment should be SS */
if ((RegMem == SOFT386_REG_EBP) && Mode)
{
/* Add a SS: prefix */
State->PrefixFlags |= SOFT386_PREFIX_SEG;
State->SegmentOverride = SOFT386_REG_SS;
}
}
if (Mode == 1)
{
CHAR Offset;
/* Fetch the byte */
if (!Soft386FetchByte(State, (PUCHAR)&Offset))
{
/* Exception occurred */
return FALSE;
}
/* Add the signed offset to the address */
ModRegRm->MemoryAddress += (LONG)Offset;
}
else if ((Mode == 2) || ((Mode == 0) && (RegMem == SOFT386_REG_EBP)))
{
LONG Offset;
/* Fetch the dword */
if (!Soft386FetchDword(State, (PULONG)&Offset))
{
/* Exception occurred */
return FALSE;
}
/* Add the signed offset to the address */
ModRegRm->MemoryAddress += Offset;
}
}
else
{
/* Check the operand */
switch (RegMem)
{
case 0:
case 2:
{
/* (SS:)[BX + SI] */
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBX].LowWord
+ State->GeneralRegs[SOFT386_REG_ESI].LowWord;
break;
}
case 1:
case 3:
{
/* (SS:)[BX + DI] */
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBX].LowWord
+ State->GeneralRegs[SOFT386_REG_EDI].LowWord;
break;
}
case 4:
{
/* [SI] */
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_ESI].LowWord;
break;
}
case 5:
{
/* [DI] */
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EDI].LowWord;
break;
}
case 6:
{
if (Mode)
{
/* [BP] */
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBP].LowWord;
}
else
{
/* [constant] (added later) */
ModRegRm->MemoryAddress = 0;
}
break;
}
case 7:
{
/* [BX] */
ModRegRm->MemoryAddress = State->GeneralRegs[SOFT386_REG_EBX].LowWord;
break;
}
}
/* Check if there is no segment override */
if (!(State->PrefixFlags & SOFT386_PREFIX_SEG))
{
/* Check if the default segment should be SS */
if ((RegMem == 2) || (RegMem == 3) || ((RegMem == 6) && Mode))
{
/* Add a SS: prefix */
State->PrefixFlags |= SOFT386_PREFIX_SEG;
State->SegmentOverride = SOFT386_REG_SS;
}
}
if (Mode == 1)
{
CHAR Offset;
/* Fetch the byte */
if (!Soft386FetchByte(State, (PUCHAR)&Offset))
{
/* Exception occurred */
return FALSE;
}
/* Add the signed offset to the address */
ModRegRm->MemoryAddress += (LONG)Offset;
}
else if ((Mode == 2) || ((Mode == 0) && (RegMem == 6)))
{
SHORT Offset;
/* Fetch the word */
if (!Soft386FetchWord(State, (PUSHORT)&Offset))
{
/* Exception occurred */
return FALSE;
}
/* Add the signed offset to the address */
ModRegRm->MemoryAddress += (LONG)Offset;
}
/* Clear the top 16 bits */
ModRegRm->MemoryAddress &= 0x0000FFFF;
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386ReadModrmByteOperands(PSOFT386_STATE State,
PSOFT386_MOD_REG_RM ModRegRm,
PUCHAR RegValue,
PUCHAR RmValue)
{
SOFT386_SEG_REGS Segment = SOFT386_REG_DS;
/* Get the register value */
if (ModRegRm->Register & 0x04)
{
/* AH, CH, DH, BH */
*RegValue = State->GeneralRegs[ModRegRm->Register & 0x03].HighByte;
}
else
{
/* AL, CL, DL, BL */
*RegValue = State->GeneralRegs[ModRegRm->Register & 0x03].LowByte;
}
if (!ModRegRm->Memory)
{
/* Get the second register value */
if (ModRegRm->SecondRegister & 0x04)
{
/* AH, CH, DH, BH */
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister & 0x03].HighByte;
}
else
{
/* AL, CL, DL, BL */
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister & 0x03].LowByte;
}
}
else
{
/* Check for the segment override */
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
{
/* Use the override segment instead */
Segment = State->SegmentOverride;
}
/* Read memory */
if (!Soft386ReadMemory(State,
Segment,
ModRegRm->MemoryAddress,
FALSE,
RmValue,
sizeof(UCHAR)))
{
/* Exception occurred */
return FALSE;
}
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386ReadModrmWordOperands(PSOFT386_STATE State,
PSOFT386_MOD_REG_RM ModRegRm,
PUSHORT RegValue,
PUSHORT RmValue)
{
SOFT386_SEG_REGS Segment = SOFT386_REG_DS;
/* Get the register value */
*RegValue = State->GeneralRegs[ModRegRm->Register].LowWord;
if (!ModRegRm->Memory)
{
/* Get the second register value */
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister].LowWord;
}
else
{
/* Check for the segment override */
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
{
/* Use the override segment instead */
Segment = State->SegmentOverride;
}
/* Read memory */
if (!Soft386ReadMemory(State,
Segment,
ModRegRm->MemoryAddress,
FALSE,
RmValue,
sizeof(USHORT)))
{
/* Exception occurred */
return FALSE;
}
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386ReadModrmDwordOperands(PSOFT386_STATE State,
PSOFT386_MOD_REG_RM ModRegRm,
PULONG RegValue,
PULONG RmValue)
{
SOFT386_SEG_REGS Segment = SOFT386_REG_DS;
/* Get the register value */
*RegValue = State->GeneralRegs[ModRegRm->Register].Long;
if (!ModRegRm->Memory)
{
/* Get the second register value */
*RmValue = State->GeneralRegs[ModRegRm->SecondRegister].Long;
}
else
{
/* Check for the segment override */
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
{
/* Use the override segment instead */
Segment = State->SegmentOverride;
}
/* Read memory */
if (!Soft386ReadMemory(State,
Segment,
ModRegRm->MemoryAddress,
FALSE,
RmValue,
sizeof(ULONG)))
{
/* Exception occurred */
return FALSE;
}
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386WriteModrmByteOperands(PSOFT386_STATE State,
PSOFT386_MOD_REG_RM ModRegRm,
BOOLEAN WriteRegister,
UCHAR Value)
{
SOFT386_SEG_REGS Segment = SOFT386_REG_DS;
if (WriteRegister)
{
/* Store the value in the register */
if (ModRegRm->Register & 0x04)
{
/* AH, CH, DH, BH */
State->GeneralRegs[ModRegRm->Register & 0x03].HighByte = Value;
}
else
{
/* AL, CL, DL, BL */
State->GeneralRegs[ModRegRm->Register & 0x03].LowByte = Value;
}
}
else
{
if (!ModRegRm->Memory)
{
/* Store the value in the second register */
if (ModRegRm->SecondRegister & 0x04)
{
/* AH, CH, DH, BH */
State->GeneralRegs[ModRegRm->SecondRegister & 0x03].HighByte = Value;
}
else
{
/* AL, CL, DL, BL */
State->GeneralRegs[ModRegRm->SecondRegister & 0x03].LowByte = Value;
}
}
else
{
/* Check for the segment override */
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
{
/* Use the override segment instead */
Segment = State->SegmentOverride;
}
/* Write memory */
if (!Soft386WriteMemory(State,
Segment,
ModRegRm->MemoryAddress,
&Value,
sizeof(UCHAR)))
{
/* Exception occurred */
return FALSE;
}
}
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386WriteModrmWordOperands(PSOFT386_STATE State,
PSOFT386_MOD_REG_RM ModRegRm,
BOOLEAN WriteRegister,
USHORT Value)
{
SOFT386_SEG_REGS Segment = SOFT386_REG_DS;
if (WriteRegister)
{
/* Store the value in the register */
State->GeneralRegs[ModRegRm->Register].LowWord = Value;
}
else
{
if (!ModRegRm->Memory)
{
/* Store the value in the second register */
State->GeneralRegs[ModRegRm->SecondRegister].LowWord = Value;
}
else
{
/* Check for the segment override */
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
{
/* Use the override segment instead */
Segment = State->SegmentOverride;
}
/* Write memory */
if (!Soft386WriteMemory(State,
Segment,
ModRegRm->MemoryAddress,
&Value,
sizeof(USHORT)))
{
/* Exception occurred */
return FALSE;
}
}
}
return TRUE;
}
FORCEINLINE
BOOLEAN
Soft386WriteModrmDwordOperands(PSOFT386_STATE State,
PSOFT386_MOD_REG_RM ModRegRm,
BOOLEAN WriteRegister,
ULONG Value)
{
SOFT386_SEG_REGS Segment = SOFT386_REG_DS;
if (WriteRegister)
{
/* Store the value in the register */
State->GeneralRegs[ModRegRm->Register].Long = Value;
}
else
{
if (!ModRegRm->Memory)
{
/* Store the value in the second register */
State->GeneralRegs[ModRegRm->SecondRegister].Long = Value;
}
else
{
/* Check for the segment override */
if (State->PrefixFlags & SOFT386_PREFIX_SEG)
{
/* Use the override segment instead */
Segment = State->SegmentOverride;
}
/* Write memory */
if (!Soft386WriteMemory(State,
Segment,
ModRegRm->MemoryAddress,
&Value,
sizeof(ULONG)))
{
/* Exception occurred */
return FALSE;
}
}
}
return TRUE;
}
/* EOF */