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[FAST486]

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The top half of EIP is cleared after a 16-bit jump.


svn path=/branches/ntvdm/; revision=61058
This commit is contained in:
Aleksandar Andrejevic 2013-11-20 14:21:47 +00:00
parent 459e3a6f48
commit f90a1db2b7
2 changed files with 32 additions and 4 deletions
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28
lib/fast486/opcodes.c
View file

@ -606,10 +606,13 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeShortConditionalJmp)
{ {
BOOLEAN Jump = FALSE; BOOLEAN Jump = FALSE;
CHAR Offset = 0; CHAR Offset = 0;
BOOLEAN Size = State->SegmentRegs[FAST486_REG_CS].Size;
/* Make sure this is the right instruction */ /* Make sure this is the right instruction */
ASSERT((Opcode & 0xF0) == 0x70); ASSERT((Opcode & 0xF0) == 0x70);
TOGGLE_OPSIZE(Size);
/* Fetch the offset */ /* Fetch the offset */
if (!Fast486FetchByte(State, (PUCHAR)&Offset)) if (!Fast486FetchByte(State, (PUCHAR)&Offset))
{ {
@ -686,6 +689,12 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeShortConditionalJmp)
{ {
/* Move the instruction pointer */ /* Move the instruction pointer */
State->InstPtr.Long += Offset; State->InstPtr.Long += Offset;
if (!Size)
{
/* Clear the top half of EIP */
State->InstPtr.Long &= 0xFFFF;
}
} }
/* Return success */ /* Return success */
@ -1058,6 +1067,9 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeOut)
FAST486_OPCODE_HANDLER(Fast486OpcodeShortJump) FAST486_OPCODE_HANDLER(Fast486OpcodeShortJump)
{ {
CHAR Offset = 0; CHAR Offset = 0;
BOOLEAN Size = State->SegmentRegs[FAST486_REG_CS].Size;
TOGGLE_OPSIZE(Size);
/* Make sure this is the right instruction */ /* Make sure this is the right instruction */
ASSERT(Opcode == 0xEB); ASSERT(Opcode == 0xEB);
@ -1072,6 +1084,12 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeShortJump)
/* Move the instruction pointer */ /* Move the instruction pointer */
State->InstPtr.Long += Offset; State->InstPtr.Long += Offset;
if (!Size)
{
/* Clear the top half of EIP */
State->InstPtr.Long &= 0xFFFF;
}
return TRUE; return TRUE;
} }
@ -5087,7 +5105,10 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeJmp)
} }
/* Move the instruction pointer */ /* Move the instruction pointer */
State->InstPtr.LowWord += Offset; State->InstPtr.Long += Offset;
/* Clear the top half of EIP */
State->InstPtr.Long &= 0xFFFF;
} }
return TRUE; return TRUE;
@ -5137,9 +5158,8 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeJmpAbs)
return FALSE; return FALSE;
} }
/* Load new (E)IP */ /* Load new EIP */
if (Size) State->InstPtr.Long = Offset; State->InstPtr.Long = Offset;
else State->InstPtr.LowWord = LOWORD(Offset);
return TRUE; return TRUE;
} }

8
lib/fast486/opgroups.c
View file

@ -1539,6 +1539,9 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeGroupFF)
/* Set the IP to the address */ /* Set the IP to the address */
State->InstPtr.LowWord = Value; State->InstPtr.LowWord = Value;
/* Clear the top half of EIP */
State->InstPtr.Long &= 0xFFFF;
} }
else if (ModRegRm.Register == 3) else if (ModRegRm.Register == 3)
{ {
@ -1588,6 +1591,8 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeGroupFF)
/* Set the IP to the address */ /* Set the IP to the address */
State->InstPtr.LowWord = Value; State->InstPtr.LowWord = Value;
/* Clear the top half of EIP */
State->InstPtr.Long &= 0xFFFF;
} }
else if (ModRegRm.Register == 4) else if (ModRegRm.Register == 4)
{ {
@ -1627,6 +1632,9 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeGroupFF)
/* Set the IP to the address */ /* Set the IP to the address */
State->InstPtr.LowWord = Value; State->InstPtr.LowWord = Value;
/* Clear the top half of EIP */
State->InstPtr.Long &= 0xFFFF;
} }
else if (ModRegRm.Register == 6) else if (ModRegRm.Register == 6)
{ {