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[FAST486]

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Duplicate prefixes don't generate #UD. Multiple segment overrides
override each other, and so do REP and REPNZ.


svn path=/trunk/; revision=67669
This commit is contained in:
Aleksandar Andrejevic 2015-05-11 18:49:10 +00:00
parent 8d53d6c2bd
commit 07a731ed1c
1 changed files with 24 additions and 83 deletions
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107
reactos/lib/fast486/opcodes.c
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@ -311,120 +311,74 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeInvalid)
FAST486_OPCODE_HANDLER(Fast486OpcodePrefix)
{
BOOLEAN Valid = FALSE;
switch (Opcode)
{
/* ES: */
case 0x26:
{
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
{
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_ES;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_ES;
break;
}
/* CS: */
case 0x2E:
{
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
{
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_CS;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_CS;
break;
}
/* SS: */
case 0x36:
{
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
{
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_SS;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_SS;
break;
}
/* DS: */
case 0x3E:
{
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
{
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_DS;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_DS;
break;
}
/* FS: */
case 0x64:
{
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
{
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_FS;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_FS;
break;
}
/* GS: */
case 0x65:
{
if (!(State->PrefixFlags & FAST486_PREFIX_SEG))
{
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_GS;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_SEG;
State->SegmentOverride = FAST486_REG_GS;
break;
}
/* OPSIZE */
case 0x66:
{
if (!(State->PrefixFlags & FAST486_PREFIX_OPSIZE))
{
State->PrefixFlags |= FAST486_PREFIX_OPSIZE;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_OPSIZE;
break;
}
/* ADSIZE */
case 0x67:
{
if (!(State->PrefixFlags & FAST486_PREFIX_ADSIZE))
{
State->PrefixFlags |= FAST486_PREFIX_ADSIZE;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_ADSIZE;
break;
}
/* LOCK */
case 0xF0:
{
if (!(State->PrefixFlags & FAST486_PREFIX_LOCK))
{
State->PrefixFlags |= FAST486_PREFIX_LOCK;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_LOCK;
break;
}
@ -432,13 +386,8 @@ FAST486_OPCODE_HANDLER(Fast486OpcodePrefix)
case 0xF2:
{
/* Mutually exclusive with REP */
if (!(State->PrefixFlags
& (FAST486_PREFIX_REPNZ | FAST486_PREFIX_REP)))
{
State->PrefixFlags |= FAST486_PREFIX_REPNZ;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_REPNZ;
State->PrefixFlags &= ~FAST486_PREFIX_REP;
break;
}
@ -446,24 +395,16 @@ FAST486_OPCODE_HANDLER(Fast486OpcodePrefix)
case 0xF3:
{
/* Mutually exclusive with REPNZ */
if (!(State->PrefixFlags
& (FAST486_PREFIX_REPNZ | FAST486_PREFIX_REP)))
{
State->PrefixFlags |= FAST486_PREFIX_REP;
Valid = TRUE;
}
State->PrefixFlags |= FAST486_PREFIX_REP;
State->PrefixFlags &= ~FAST486_PREFIX_REPNZ;
break;
}
}
if (!Valid)
{
/* Clear all prefixes */
State->PrefixFlags = 0;
/* Throw an exception */
Fast486Exception(State, FAST486_EXCEPTION_UD);
default:
{
/* Shouldn't happen */
ASSERT(FALSE);
}
}
}