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[FAST486]

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Whether stack operations use ESP or SP depends on the size of the stack segment.


svn path=/trunk/; revision=67320
This commit is contained in:
Aleksandar Andrejevic 2015-04-20 00:36:46 +00:00
parent 43ee605045
commit 08077d0820
1 changed files with 27 additions and 6 deletions
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33
reactos/lib/fast486/common.inl
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@ -301,6 +301,7 @@ Fast486StackPush(PFAST486_STATE State,
ULONG Value)
{
BOOLEAN Size = State->SegmentRegs[FAST486_REG_CS].Size;
ULONG StackPointer = State->GeneralRegs[FAST486_REG_ESP].Long;
/* The OPSIZE prefix toggles the size */
TOGGLE_OPSIZE(Size);
@ -320,7 +321,9 @@ Fast486StackPush(PFAST486_STATE State,
/* Store the value in SS:[ESP - 4] */
if (!Fast486WriteMemory(State,
FAST486_REG_SS,
State->GeneralRegs[FAST486_REG_ESP].Long - sizeof(ULONG),
State->SegmentRegs[FAST486_REG_SS].Size
? StackPointer - sizeof(ULONG)
: LOWORD(StackPointer - sizeof(ULONG)),
&Value,
sizeof(ULONG)))
{
@ -328,8 +331,16 @@ Fast486StackPush(PFAST486_STATE State,
return FALSE;
}
/* Subtract ESP by 4 */
State->GeneralRegs[FAST486_REG_ESP].Long -= sizeof(ULONG);
if (State->SegmentRegs[FAST486_REG_SS].Size)
{
/* Subtract ESP by 4 */
State->GeneralRegs[FAST486_REG_ESP].Long -= sizeof(ULONG);
}
else
{
/* Subtract SP by 4 */
State->GeneralRegs[FAST486_REG_ESP].LowWord -= sizeof(ULONG);
}
}
else
{
@ -346,7 +357,9 @@ Fast486StackPush(PFAST486_STATE State,
/* Store the value in SS:[SP - 2] */
if (!Fast486WriteMemory(State,
FAST486_REG_SS,
LOWORD(State->GeneralRegs[FAST486_REG_ESP].LowWord - sizeof(USHORT)),
State->SegmentRegs[FAST486_REG_SS].Size
? StackPointer - sizeof(USHORT)
: LOWORD(StackPointer - sizeof(USHORT)),
&ShortValue,
sizeof(USHORT)))
{
@ -354,8 +367,16 @@ Fast486StackPush(PFAST486_STATE State,
return FALSE;
}
/* Subtract SP by 2 */
State->GeneralRegs[FAST486_REG_ESP].LowWord -= sizeof(USHORT);
if (State->SegmentRegs[FAST486_REG_SS].Size)
{
/* Subtract ESP by 2 */
State->GeneralRegs[FAST486_REG_ESP].Long -= sizeof(USHORT);
}
else
{
/* Subtract SP by 2 */
State->GeneralRegs[FAST486_REG_ESP].LowWord -= sizeof(USHORT);
}
}
return TRUE;