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[FAST486]

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Fix UnsignedDivMod128 (again).
Fix Fast486FpuAdd to handle numbers whose difference of exponents is greater than
the number of bits in the mantissa.


svn path=/trunk/; revision=67827
This commit is contained in:
Aleksandar Andrejevic 2015-05-19 02:37:17 +00:00
parent 3bdb6b6e45
commit 94d8c8c4b2
1 changed files with 30 additions and 5 deletions
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35
reactos/lib/fast486/fpu.c
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@ -204,9 +204,16 @@ UnsignedDivMod128(ULONGLONG DividendLow,
* divisor has more than the original divisor * divisor has more than the original divisor
*/ */
Bits = CountLeadingZeros64(Divisor); Bits = CountLeadingZeros64(Divisor);
if (CurrentHigh > 0ULL) Bits -= CountLeadingZeros64(CurrentHigh); if (CurrentHigh > 0ULL) Bits += 64 - CountLeadingZeros64(CurrentHigh);
else Bits -= CountLeadingZeros64(CurrentLow); else Bits -= CountLeadingZeros64(CurrentLow);
if (Bits >= 64)
{
*QuotientHigh = *QuotientLow;
*QuotientLow = 0ULL;
Bits -= 64;
}
if (Bits) if (Bits)
{ {
/* Shift the quotient left by that amount */ /* Shift the quotient left by that amount */
@ -635,15 +642,33 @@ Fast486FpuAdd(PFAST486_STATE State,
/* Adjust the first operand to it... */ /* Adjust the first operand to it... */
if (FirstAdjusted.Exponent < TempResult.Exponent) if (FirstAdjusted.Exponent < TempResult.Exponent)
{ {
FirstAdjusted.Mantissa >>= (TempResult.Exponent - FirstAdjusted.Exponent); if ((TempResult.Exponent - FirstAdjusted.Exponent) < 64)
FirstAdjusted.Exponent = TempResult.Exponent; {
FirstAdjusted.Mantissa >>= (TempResult.Exponent - FirstAdjusted.Exponent);
FirstAdjusted.Exponent = TempResult.Exponent;
}
else
{
/* The second operand is the result */
*Result = *SecondOperand;
return TRUE;
}
} }
/* ... and the second one too */ /* ... and the second one too */
if (SecondAdjusted.Exponent < TempResult.Exponent) if (SecondAdjusted.Exponent < TempResult.Exponent)
{ {
SecondAdjusted.Mantissa >>= (TempResult.Exponent - SecondAdjusted.Exponent); if ((TempResult.Exponent - FirstAdjusted.Exponent) < 64)
SecondAdjusted.Exponent = TempResult.Exponent; {
SecondAdjusted.Mantissa >>= (TempResult.Exponent - SecondAdjusted.Exponent);
SecondAdjusted.Exponent = TempResult.Exponent;
}
else
{
/* The first operand is the result */
*Result = *FirstOperand;
return TRUE;
}
} }
if (FirstAdjusted.Sign == SecondAdjusted.Sign) if (FirstAdjusted.Sign == SecondAdjusted.Sign)