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[SOFT386]

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Halfplement the IRET instruction (everything except task switching).


svn path=/branches/ntvdm/; revision=60392
This commit is contained in:
Aleksandar Andrejevic 2013-09-27 21:18:09 +00:00
parent e05e583e56
commit 78e8653765
3 changed files with 217 additions and 4 deletions
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2
lib/soft386/common.h
View file

@ -18,6 +18,8 @@
#define SIGN_FLAG_BYTE 0x80
#define SIGN_FLAG_WORD 0x8000
#define SIGN_FLAG_LONG 0x80000000
#define REAL_MODE_FLAGS_MASK 0x17FD5
#define PROT_MODE_FLAGS_MASK 0x10DD5
#define GET_SEGMENT_RPL(s) ((s) & 3)
#define GET_SEGMENT_INDEX(s) ((s) & 0xFFF8)

2
lib/soft386/common.inl
View file

@ -162,7 +162,7 @@ Soft386LoadSegment(PSOFT386_STATE State,
CachedDescriptor = &State->SegmentRegs[Segment];
/* Check for protected mode */
if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
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))

217
lib/soft386/opcodes.c
View file

@ -4690,10 +4690,221 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeInt)
SOFT386_OPCODE_HANDLER(Soft386OpcodeIret)
{
// TODO: NOT IMPLEMENTED
UNIMPLEMENTED;
INT i;
ULONG InstPtr, CodeSel, StackPtr, StackSel;
SOFT386_FLAGS_REG NewFlags;
BOOLEAN Size = State->SegmentRegs[SOFT386_REG_CS].Size;
return FALSE;
/* Make sure this is the right instruction */
ASSERT(Opcode == 0xCF);
if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
{
/* Invalid prefix */
Soft386Exception(State, SOFT386_EXCEPTION_UD);
return FALSE;
}
if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
{
/* The OPSIZE prefix toggles the size */
Size = !Size;
}
/* Pop EIP */
if (!Soft386StackPop(State, &InstPtr))
{
/* Exception occurred */
return FALSE;
}
/* Pop CS */
if (!Soft386StackPop(State, &CodeSel))
{
/* Exception occurred */
return FALSE;
}
/* Pop EFLAGS */
if (!Soft386StackPop(State, &NewFlags.Long))
{
/* Exception occurred */
return FALSE;
}
/* Check for protected mode */
if (State->ControlRegisters[SOFT386_REG_CR0] & SOFT386_CR0_PE)
{
INT Cpl = Soft386GetCurrentPrivLevel(State);
if (State->Flags.Vm)
{
/* Return from VM86 mode */
/* Check the IOPL */
if (State->Flags.Iopl == 3)
{
/* Set new EIP */
State->InstPtr.Long = LOWORD(InstPtr);
/* Load new CS */
if (!Soft386LoadSegment(State, SOFT386_REG_CS, CodeSel))
{
/* Exception occurred */
return FALSE;
}
/* Set the new flags */
if (Size) State->Flags.Long = NewFlags.Long & REAL_MODE_FLAGS_MASK;
else State->Flags.LowWord = NewFlags.LowWord & REAL_MODE_FLAGS_MASK;
State->Flags.AlwaysSet = State->Flags.Vm = TRUE;
State->Flags.Iopl = 3;
}
else
{
/* Call the VM86 monitor */
Soft386ExceptionWithErrorCode(State, SOFT386_EXCEPTION_GP, 0);
return FALSE;
}
return TRUE;
}
if (State->Flags.Nt)
{
/* Nested task return */
UNIMPLEMENTED;
return FALSE;
}
if (NewFlags.Vm)
{
/* Return to VM86 mode */
ULONG Es, Ds, Fs, Gs;
/* Pop ESP, SS, ES, FS, GS */
if (!Soft386StackPop(State, &StackPtr)) return FALSE;
if (!Soft386StackPop(State, &StackSel)) return FALSE;
if (!Soft386StackPop(State, &Es)) return FALSE;
if (!Soft386StackPop(State, &Ds)) return FALSE;
if (!Soft386StackPop(State, &Fs)) return FALSE;
if (!Soft386StackPop(State, &Gs)) return FALSE;
/* Load the new segments */
if (!Soft386LoadSegment(State, SOFT386_REG_CS, CodeSel)) return FALSE;
if (!Soft386LoadSegment(State, SOFT386_REG_SS, StackSel)) return FALSE;
if (!Soft386LoadSegment(State, SOFT386_REG_ES, Es)) return FALSE;
if (!Soft386LoadSegment(State, SOFT386_REG_DS, Ds)) return FALSE;
if (!Soft386LoadSegment(State, SOFT386_REG_FS, Fs)) return FALSE;
if (!Soft386LoadSegment(State, SOFT386_REG_GS, Gs)) return FALSE;
/* Set the new IP */
State->InstPtr.Long = LOWORD(InstPtr);
/* Set the new flags */
if (Size) State->Flags.Long = NewFlags.Long & REAL_MODE_FLAGS_MASK;
else State->Flags.LowWord = NewFlags.LowWord & REAL_MODE_FLAGS_MASK;
State->Flags.AlwaysSet = State->Flags.Vm = TRUE;
return TRUE;
}
/* Load the new CS */
if (!Soft386LoadSegment(State, SOFT386_REG_CS, CodeSel))
{
/* Exception occurred */
return FALSE;
}
/* Set EIP */
if (Size) State->InstPtr.Long = InstPtr;
else State->InstPtr.LowWord = LOWORD(InstPtr);
if (GET_SEGMENT_RPL(CodeSel) > Cpl)
{
/* Pop ESP */
if (!Soft386StackPop(State, &StackPtr))
{
/* Exception */
return FALSE;
}
/* Pop SS */
if (!Soft386StackPop(State, &StackSel))
{
/* Exception */
return FALSE;
}
/* Load new SS */
if (!Soft386LoadSegment(State, SOFT386_REG_SS, StackSel))
{
/* Exception */
return FALSE;
}
/* Set ESP */
if (Size) State->GeneralRegs[SOFT386_REG_ESP].Long = StackPtr;
else State->GeneralRegs[SOFT386_REG_ESP].LowWord = LOWORD(StackPtr);
}
/* Set the new flags */
if (Size) State->Flags.Long = NewFlags.Long & PROT_MODE_FLAGS_MASK;
else State->Flags.LowWord = NewFlags.LowWord & PROT_MODE_FLAGS_MASK;
State->Flags.AlwaysSet = TRUE;
/* Set additional flags */
if (Cpl <= State->Flags.Iopl) State->Flags.If = NewFlags.If;
if (Cpl == 0) State->Flags.Iopl = NewFlags.Iopl;
if (GET_SEGMENT_RPL(CodeSel) > Cpl)
{
/* Update the CPL */
Cpl = Soft386GetCurrentPrivLevel(State);
/* Check segment security */
for (i = 0; i <= SOFT386_NUM_SEG_REGS; i++)
{
/* Don't check CS or SS */
if ((i == SOFT386_REG_CS) || (i == SOFT386_REG_SS)) continue;
if ((Cpl > State->SegmentRegs[i].Dpl)
&& (!State->SegmentRegs[i].Executable
|| !State->SegmentRegs[i].DirConf))
{
/* Load the NULL descriptor in the segment */
if (!Soft386LoadSegment(State, i, 0)) return FALSE;
}
}
}
}
else
{
if (Size && (InstPtr & 0xFFFF0000))
{
/* Invalid */
Soft386ExceptionWithErrorCode(State, SOFT386_EXCEPTION_GP, 0);
return FALSE;
}
/* Set new EIP */
State->InstPtr.Long = InstPtr;
/* Load new CS */
if (!Soft386LoadSegment(State, SOFT386_REG_CS, CodeSel))
{
/* Exception occurred */
return FALSE;
}
/* Set the new flags */
if (Size) State->Flags.Long = NewFlags.Long & REAL_MODE_FLAGS_MASK;
else State->Flags.LowWord = NewFlags.LowWord & REAL_MODE_FLAGS_MASK;
State->Flags.AlwaysSet = TRUE;
}
return TRUE;
}
SOFT386_OPCODE_HANDLER(Soft386OpcodeAam)