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[FAST486]

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The current "fast" method used in MOVS gives incorrect results. It has been temporarily
replaced with a slow method that works correctly.
The string functions do nothing when CX is 0 on entry, fix CMPS and SCAS.


svn path=/branches/ntvdm/; revision=61203
This commit is contained in:
Aleksandar Andrejevic 2013-12-03 00:12:55 +00:00
parent 84662d3de9
commit e7a6deb93f
1 changed files with 81 additions and 145 deletions
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226
lib/fast486/opcodes.c
View file

@ -5363,176 +5363,90 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeMovs)
Segment = State->SegmentOverride;
}
if (State->PrefixFlags & FAST486_PREFIX_REP)
{
if ((AddressSize && (State->GeneralRegs[FAST486_REG_ECX].Long == 0))
|| (!AddressSize && (State->GeneralRegs[FAST486_REG_ECX].LowWord == 0)))
{
/* Do nothing */
return TRUE;
}
}
/* Calculate the size */
if (Opcode == 0xA4) DataSize = sizeof(UCHAR);
else DataSize = OperandSize ? sizeof(ULONG) : sizeof(USHORT);
if (State->PrefixFlags & FAST486_PREFIX_REP)
/* Read from the source operand */
if (!Fast486ReadMemory(State,
Segment,
AddressSize ? State->GeneralRegs[FAST486_REG_ESI].Long
: State->GeneralRegs[FAST486_REG_ESI].LowWord,
FALSE,
&Data,
DataSize))
{
UCHAR Block[STRING_BLOCK_SIZE];
ULONG Count = AddressSize ? State->GeneralRegs[FAST486_REG_ECX].Long
: State->GeneralRegs[FAST486_REG_ECX].LowWord;
/* Exception occurred */
return FALSE;
}
/* Clear the memory block */
RtlZeroMemory(Block, sizeof(Block));
/* Write to the destination operand */
if (!Fast486WriteMemory(State,
FAST486_REG_ES,
AddressSize ? State->GeneralRegs[FAST486_REG_EDI].Long
: State->GeneralRegs[FAST486_REG_EDI].LowWord,
&Data,
DataSize))
{
/* Exception occurred */
return FALSE;
}
/* Transfer until finished */
while (Count)
/* Increment/decrement ESI and EDI */
if (AddressSize)
{
if (!State->Flags.Df)
{
ULONG Processed = min(Count, STRING_BLOCK_SIZE / DataSize);
/* Simulate the 16-bit wrap-around of SI and DI in 16-bit address mode */
if (!AddressSize)
{
ULONG MaxBytesSrc = State->Flags.Df
? (ULONG)State->GeneralRegs[FAST486_REG_ESI].LowWord
: (0x10000 - (ULONG)State->GeneralRegs[FAST486_REG_ESI].LowWord);
ULONG MaxBytesDest = State->Flags.Df
? (ULONG)State->GeneralRegs[FAST486_REG_EDI].LowWord
: (0x10000 - (ULONG)State->GeneralRegs[FAST486_REG_EDI].LowWord);
Processed = min(Processed, min(MaxBytesSrc, MaxBytesDest) / DataSize);
if (Processed == 0) Processed = 1;
}
if (State->Flags.Df)
{
/* Move ESI and EDI to the start of the block */
if (AddressSize)
{
State->GeneralRegs[FAST486_REG_ESI].Long -= (Processed - 1) * DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long -= (Processed - 1) * DataSize;
}
else
{
State->GeneralRegs[FAST486_REG_ESI].LowWord -= (Processed - 1) * DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord -= (Processed - 1) * DataSize;
}
}
/* Read from memory */
if (!Fast486ReadMemory(State,
Segment,
AddressSize ? State->GeneralRegs[FAST486_REG_ESI].Long
: State->GeneralRegs[FAST486_REG_ESI].LowWord,
FALSE,
Block,
Processed * DataSize))
{
/* Set ECX */
if (AddressSize) State->GeneralRegs[FAST486_REG_ECX].Long = Count;
else State->GeneralRegs[FAST486_REG_ECX].LowWord = LOWORD(Count);
/* Exception occurred */
return FALSE;
}
/* Write to memory */
if (!Fast486WriteMemory(State,
FAST486_REG_ES,
AddressSize ? State->GeneralRegs[FAST486_REG_EDI].Long
: State->GeneralRegs[FAST486_REG_EDI].LowWord,
Block,
Processed * DataSize))
{
/* Set ECX */
if (AddressSize) State->GeneralRegs[FAST486_REG_ECX].Long = Count;
else State->GeneralRegs[FAST486_REG_ECX].LowWord = LOWORD(Count);
/* Exception occurred */
return FALSE;
}
if (!State->Flags.Df)
{
/* Increase ESI and EDI by the number of bytes transfered */
if (AddressSize)
{
State->GeneralRegs[FAST486_REG_ESI].Long += Processed * DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long += Processed * DataSize;
}
else
{
State->GeneralRegs[FAST486_REG_ESI].LowWord += Processed * DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord += Processed * DataSize;
}
}
else
{
/* Reduce ESI and EDI */
if (AddressSize)
{
State->GeneralRegs[FAST486_REG_ESI].Long -= DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long -= DataSize;
}
else
{
State->GeneralRegs[FAST486_REG_ESI].LowWord -= DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord -= DataSize;
}
}
/* Reduce the total count by the number processed in this run */
Count -= Processed;
State->GeneralRegs[FAST486_REG_ESI].Long += DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long += DataSize;
}
else
{
State->GeneralRegs[FAST486_REG_ESI].Long -= DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long -= DataSize;
}
/* Clear ECX */
if (AddressSize) State->GeneralRegs[FAST486_REG_ECX].Long = 0;
else State->GeneralRegs[FAST486_REG_ECX].LowWord = 0;
}
else
{
/* Read from the source operand */
if (!Fast486ReadMemory(State,
FAST486_REG_DS,
AddressSize ? State->GeneralRegs[FAST486_REG_ESI].Long
: State->GeneralRegs[FAST486_REG_ESI].LowWord,
FALSE,
&Data,
DataSize))
if (!State->Flags.Df)
{
/* Exception occurred */
return FALSE;
State->GeneralRegs[FAST486_REG_ESI].LowWord += DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord += DataSize;
}
/* Write to the destination operand */
if (!Fast486WriteMemory(State,
FAST486_REG_ES,
AddressSize ? State->GeneralRegs[FAST486_REG_EDI].Long
: State->GeneralRegs[FAST486_REG_EDI].LowWord,
&Data,
DataSize))
else
{
/* Exception occurred */
return FALSE;
State->GeneralRegs[FAST486_REG_ESI].LowWord -= DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord -= DataSize;
}
}
/* Increment/decrement ESI and EDI */
// FIXME: This method is slow!
if (State->PrefixFlags & FAST486_PREFIX_REP)
{
if (AddressSize)
{
if (!State->Flags.Df)
if (--State->GeneralRegs[FAST486_REG_ECX].Long)
{
State->GeneralRegs[FAST486_REG_ESI].Long += DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long += DataSize;
}
else
{
State->GeneralRegs[FAST486_REG_ESI].Long -= DataSize;
State->GeneralRegs[FAST486_REG_EDI].Long -= DataSize;
/* Repeat the instruction */
State->InstPtr = State->SavedInstPtr;
}
}
else
{
if (!State->Flags.Df)
if (--State->GeneralRegs[FAST486_REG_ECX].LowWord)
{
State->GeneralRegs[FAST486_REG_ESI].LowWord += DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord += DataSize;
}
else
{
State->GeneralRegs[FAST486_REG_ESI].LowWord -= DataSize;
State->GeneralRegs[FAST486_REG_EDI].LowWord -= DataSize;
/* Repeat the instruction */
State->InstPtr = State->SavedInstPtr;
}
}
}
@ -5562,6 +5476,17 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeCmps)
Segment = State->SegmentOverride;
}
if ((State->PrefixFlags & FAST486_PREFIX_REP)
|| (State->PrefixFlags & FAST486_PREFIX_REPNZ))
{
if ((AddressSize && (State->GeneralRegs[FAST486_REG_ECX].Long == 0))
|| (!AddressSize && (State->GeneralRegs[FAST486_REG_ECX].LowWord == 0)))
{
/* Do nothing */
return TRUE;
}
}
/* Calculate the size */
if (Opcode == 0xA6) DataSize = sizeof(UCHAR);
else DataSize = OperandSize ? sizeof(ULONG) : sizeof(USHORT);
@ -5909,6 +5834,17 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeScas)
TOGGLE_OPSIZE(OperandSize);
TOGGLE_ADSIZE(AddressSize);
if ((State->PrefixFlags & FAST486_PREFIX_REP)
|| (State->PrefixFlags & FAST486_PREFIX_REPNZ))
{
if ((AddressSize && (State->GeneralRegs[FAST486_REG_ECX].Long == 0))
|| (!AddressSize && (State->GeneralRegs[FAST486_REG_ECX].LowWord == 0)))
{
/* Do nothing */
return TRUE;
}
}
/* Calculate the size */
if (Opcode == 0xAE) DataSize = sizeof(UCHAR);
else DataSize = OperandSize ? sizeof(ULONG) : sizeof(USHORT);