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[FAST486]

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Fix a copy-paste bug. Adjust the number when subtracting in Fast486FpuAdd. Don't overflow
the mantissa in Fast486FpuToSingle/Fast486FpuToDouble without correcting the exponent.


svn path=/trunk/; revision=67838
This commit is contained in:
Aleksandar Andrejevic 2015-05-20 23:16:36 +00:00
parent fd3f43887a
commit b0aa61088d
1 changed files with 56 additions and 23 deletions
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79
reactos/lib/fast486/fpu.c
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@ -430,14 +430,14 @@ Fast486FpuToSingleReal(PFAST486_STATE State,
/* Calculate the remainder */
Remainder = Value->Mantissa & ((1ULL << 40) - 1);
/* Store the biased exponent */
*Result |= (ULONG)(UnbiasedExp + FPU_REAL4_BIAS) << 23;
/* Perform rounding */
Result64 = (ULONGLONG)*Result;
Fast486FpuRound(State, &Result64, Value->Sign, Remainder, 39);
*Result = (ULONG)Result64;
/* Store the biased exponent */
*Result |= (ULONG)(UnbiasedExp + FPU_REAL4_BIAS) << 23;
SetSign:
if (Value->Sign) *Result |= 0x80000000;
@ -529,12 +529,12 @@ Fast486FpuToDoubleReal(PFAST486_STATE State,
/* Calculate the remainder */
Remainder = Value->Mantissa & ((1 << 11) - 1);
/* Perform rounding */
Fast486FpuRound(State, Result, Value->Sign, Remainder, 10);
/* Store the biased exponent */
*Result |= (ULONGLONG)(UnbiasedExp + FPU_REAL8_BIAS) << 52;
/* Perform rounding */
Fast486FpuRound(State, Result, Value->Sign, Remainder, 10);
SetSign:
if (Value->Sign) *Result |= 1ULL << 63;
@ -658,7 +658,7 @@ Fast486FpuAdd(PFAST486_STATE State,
/* ... and the second one too */
if (SecondAdjusted.Exponent < TempResult.Exponent)
{
if ((TempResult.Exponent - FirstAdjusted.Exponent) < 64)
if ((TempResult.Exponent - SecondAdjusted.Exponent) < 64)
{
SecondAdjusted.Mantissa >>= (TempResult.Exponent - SecondAdjusted.Exponent);
SecondAdjusted.Exponent = TempResult.Exponent;
@ -693,31 +693,64 @@ Fast486FpuAdd(PFAST486_STATE State,
}
/* Did it overflow? */
if (FPU_IS_NORMALIZED(&FirstAdjusted) && FPU_IS_NORMALIZED(&SecondAdjusted))
if (FirstAdjusted.Sign == SecondAdjusted.Sign)
{
if (TempResult.Exponent == FPU_MAX_EXPONENT)
if (TempResult.Mantissa < FirstAdjusted.Mantissa
|| TempResult.Mantissa < SecondAdjusted.Mantissa)
{
/* Raise the overflow exception */
State->FpuStatus.Oe = TRUE;
if (State->FpuControl.Om)
if (TempResult.Exponent == FPU_MAX_EXPONENT)
{
/* Total overflow, return infinity */
TempResult.Mantissa = FPU_MANTISSA_HIGH_BIT;
TempResult.Exponent = FPU_MAX_EXPONENT + 1;
/* Raise the overflow exception */
State->FpuStatus.Oe = TRUE;
if (State->FpuControl.Om)
{
/* Total overflow, return infinity */
TempResult.Mantissa = FPU_MANTISSA_HIGH_BIT;
TempResult.Exponent = FPU_MAX_EXPONENT + 1;
}
else
{
Fast486FpuException(State);
return FALSE;
}
}
else
{
Fast486FpuException(State);
return FALSE;
/* Lose the LSB in favor of the carry */
TempResult.Mantissa >>= 1;
TempResult.Mantissa |= FPU_MANTISSA_HIGH_BIT;
TempResult.Exponent++;
}
}
else
}
else
{
if (TempResult.Mantissa >= FirstAdjusted.Mantissa
&& TempResult.Mantissa >= SecondAdjusted.Mantissa)
{
/* Lose the LSB in favor of the carry */
TempResult.Mantissa >>= 1;
TempResult.Mantissa |= FPU_MANTISSA_HIGH_BIT;
TempResult.Exponent++;
if (TempResult.Exponent == 0)
{
/* Raise the underflow exception */
State->FpuStatus.Ue = TRUE;
if (State->FpuControl.Um)
{
/* Total overflow, return zero */
TempResult.Mantissa = 0ULL;
}
else
{
Fast486FpuException(State);
return FALSE;
}
}
else
{
/* Lose the MSB */
TempResult.Mantissa <<= 1;
TempResult.Exponent--;
}
}
}