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[FAST486]

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Fix the 3-byte IMUL instruction. If the operand size is 16-bit, the
result should be written in 16-bit too.


svn path=/branches/ntvdm/; revision=60963
This commit is contained in:
Aleksandar Andrejevic 2013-11-12 18:21:30 +00:00
parent cf559336a1
commit 0aed89f779
1 changed files with 21 additions and 11 deletions
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32
lib/fast486/opcodes.c
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@ -3595,7 +3595,6 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeImulModrmImm)
BOOLEAN OperandSize, AddressSize; BOOLEAN OperandSize, AddressSize;
FAST486_MOD_REG_RM ModRegRm; FAST486_MOD_REG_RM ModRegRm;
LONG Multiplier; LONG Multiplier;
LONGLONG Product;
/* Make sure this is the right instruction */ /* Make sure this is the right instruction */
ASSERT((Opcode & 0xFD) == 0x69); ASSERT((Opcode & 0xFD) == 0x69);
@ -3658,6 +3657,7 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeImulModrmImm)
if (OperandSize) if (OperandSize)
{ {
LONG RegValue, Multiplicand; LONG RegValue, Multiplicand;
LONGLONG Product;
/* Read the operands */ /* Read the operands */
if (!Fast486ReadModrmDwordOperands(State, if (!Fast486ReadModrmDwordOperands(State,
@ -3671,10 +3671,20 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeImulModrmImm)
/* Multiply */ /* Multiply */
Product = (LONGLONG)Multiplicand * (LONGLONG)Multiplier; Product = (LONGLONG)Multiplicand * (LONGLONG)Multiplier;
/* Check for carry/overflow */
State->Flags.Cf = State->Flags.Of = ((Product < MINLONG) || (Product > MAXLONG));
/* Write-back the result */
return Fast486WriteModrmDwordOperands(State,
&ModRegRm,
TRUE,
(ULONG)((LONG)Product));
} }
else else
{ {
SHORT RegValue, Multiplicand; SHORT RegValue, Multiplicand;
LONG Product;
/* Read the operands */ /* Read the operands */
if (!Fast486ReadModrmWordOperands(State, if (!Fast486ReadModrmWordOperands(State,
@ -3687,17 +3697,17 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeImulModrmImm)
} }
/* Multiply */ /* Multiply */
Product = (LONGLONG)Multiplicand * (LONGLONG)Multiplier; Product = (LONG)Multiplicand * (LONG)Multiplier;
/* Check for carry/overflow */
State->Flags.Cf = State->Flags.Of = ((Product < MINSHORT) || (Product > MAXSHORT));
/* Write-back the result */
return Fast486WriteModrmWordOperands(State,
&ModRegRm,
TRUE,
(USHORT)((SHORT)Product));
} }
/* Check for carry/overflow */
State->Flags.Cf = State->Flags.Of = ((Product < MINLONG) || (Product > MAXLONG));
/* Write-back the result */
return Fast486WriteModrmDwordOperands(State,
&ModRegRm,
TRUE,
(ULONG)((LONG)Product));
} }
FAST486_OPCODE_HANDLER(Fast486OpcodePushByteImm) FAST486_OPCODE_HANDLER(Fast486OpcodePushByteImm)