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[FAST486]
Halfplement floating point division. Halfplement opcode 0xD9. svn path=/trunk/; revision=65945
This commit is contained in:
Aleksandar Andrejevic
parent
af8ae44bc4
commit
d8f89bc80c
3 changed files with 253 additions and 18 deletions
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@ -1528,12 +1528,17 @@ Fast486FpuNormalize(PFAST486_STATE State,
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}
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else
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{
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/* Make it denormalized */
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Data->Mantissa <<= Data->Exponent - 1;
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Data->Exponent = 1;
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/* Underflow */
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State->FpuStatus.Ue = TRUE;
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if (State->FpuControl.Um)
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{
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/* Make it denormalized */
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Data->Mantissa <<= Data->Exponent - 1;
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Data->Exponent = 1;
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}
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else
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{
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/* Raise the underflow exception */
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State->FpuStatus.Ue = TRUE;
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}
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}
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}
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@ -1560,7 +1565,7 @@ Fast486FpuPush(PFAST486_STATE State,
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FPU_ST(0) = *Data;
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FPU_SET_TAG(0, Fast486GetValueTag(Data));
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}
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else State->FpuStatus.Ie = TRUE;
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else State->FpuStatus.Sf = TRUE;
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}
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FORCEINLINE
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@ -1573,7 +1578,7 @@ Fast486FpuPop(PFAST486_STATE State)
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FPU_SET_TAG(0, FPU_TAG_EMPTY);
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State->FpuStatus.Top++;
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}
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else State->FpuStatus.Ie = TRUE;
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else State->FpuStatus.Sf = TRUE;
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}
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#endif
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@ -66,6 +66,77 @@ UnsignedMult128(ULONGLONG Multiplicand,
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return LowProduct;
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}
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static ULONGLONG
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UnsignedDivMod128(ULONGLONG DividendLow,
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ULONGLONG DividendHigh,
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ULONGLONG Divisor,
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PULONGLONG QuotientLow,
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PULONGLONG QuotientHigh)
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{
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ULONGLONG ValueLow = DividendLow;
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ULONGLONG ValueHigh = DividendHigh;
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ULONGLONG CurrentLow = 0ULL;
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ULONGLONG CurrentHigh = Divisor;
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ULONG Bits;
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ASSERT(Divisor != 0ULL);
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/* Initialize the quotient */
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*QuotientLow = *QuotientHigh = 0ULL;
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/* Normalize the current divisor */
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Bits = CountLeadingZeros64(CurrentHigh);
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CurrentHigh <<= Bits;
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/* Loop while the value is higher than or equal to the original divisor */
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while ((ValueHigh > 0ULL) || (ValueLow >= Divisor))
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{
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/* Shift the quotient left by one bit */
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*QuotientHigh <<= 1;
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*QuotientHigh |= *QuotientLow >> 63;
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*QuotientLow <<= 1;
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/* Check if the value is higher than or equal to the current divisor */
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if ((ValueHigh > CurrentHigh)
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|| ((ValueHigh == CurrentHigh) && (ValueLow >= CurrentLow)))
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{
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BOOLEAN Carry = ValueLow < CurrentLow;
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/* Subtract the current divisor from the value */
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ValueHigh -= CurrentHigh;
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ValueLow -= CurrentLow;
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if (Carry) ValueHigh--;
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/* Set the lowest bit of the quotient */
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*QuotientLow |= 1;
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}
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/* Shift the current divisor right by one bit */
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CurrentLow >>= 1;
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CurrentLow |= (CurrentHigh & 1) << 63;
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CurrentHigh >>= 1;
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}
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/*
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* Calculate the number of significant bits the current
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* divisor has more than the original divisor
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*/
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Bits = CountLeadingZeros64(Divisor) + 64;
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Bits -= (CurrentHigh > 0ULL) ? CountLeadingZeros64(CurrentHigh) : 64;
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Bits -= (CurrentLow > 0ULL) ? CountLeadingZeros64(CurrentLow) : 64;
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if (Bits)
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{
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/* Shift the quotient left by that amount */
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*QuotientHigh <<= Bits;
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*QuotientHigh |= *QuotientLow >> (64 - Bits);
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*QuotientLow <<= Bits;
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}
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/* Return the remainder */
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return ValueLow;
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}
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static inline VOID FASTCALL
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Fast486FpuFromInteger(PFAST486_STATE State,
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LONGLONG Value,
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@ -557,8 +628,31 @@ Fast486FpuDivide(PFAST486_STATE State,
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PFAST486_FPU_DATA_REG Result)
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{
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FAST486_FPU_DATA_REG TempResult;
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ULONGLONG QuotientLow, QuotientHigh, Remainder;
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LONG Exponent;
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if (FPU_IS_ZERO(SecondOperand))
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if (FPU_IS_INDEFINITE(FirstOperand)
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|| FPU_IS_INDEFINITE(SecondOperand)
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|| (FPU_IS_INFINITY(FirstOperand) && FPU_IS_INFINITY(SecondOperand))
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|| (FPU_IS_ZERO(FirstOperand) && FPU_IS_ZERO(SecondOperand)))
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{
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if (State->FpuControl.Im)
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{
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/* Return the indefinite NaN */
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Result->Sign = TRUE;
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Result->Exponent = FPU_MAX_EXPONENT + 1;
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Result->Mantissa = FPU_INDEFINITE_MANTISSA;
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}
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else
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{
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/* Raise the invalid operation exception */
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State->FpuStatus.Ie = TRUE;
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}
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return;
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}
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if (FPU_IS_ZERO(SecondOperand) || FPU_IS_INFINITY(FirstOperand))
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{
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if (State->FpuControl.Zm)
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{
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@ -571,16 +665,75 @@ Fast486FpuDivide(PFAST486_STATE State,
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{
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/* Raise the division by zero exception */
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State->FpuStatus.Ze = TRUE;
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return;
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}
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return;
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}
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TempResult.Exponent = FirstOperand->Exponent - SecondOperand->Exponent;
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/* Calculate the sign of the result */
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TempResult.Sign = FirstOperand->Sign ^ SecondOperand->Sign;
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// TODO: NOT IMPLEMENTED
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UNREFERENCED_PARAMETER(TempResult);
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UNIMPLEMENTED;
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if (FPU_IS_ZERO(FirstOperand) || FPU_IS_INFINITY(SecondOperand))
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{
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/* Return zero */
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Result->Sign = TempResult.Sign;
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Result->Mantissa = 0ULL;
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Result->Exponent = 0;
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return;
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}
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/* Calculate the exponent of the result */
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Exponent = (LONG)FirstOperand->Exponent - (LONG)SecondOperand->Exponent - 64;
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/* Divide the two mantissas */
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Remainder = UnsignedDivMod128(0ULL,
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/* Notice the 64 above - this is the high part */
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FirstOperand->Mantissa,
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SecondOperand->Mantissa,
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&QuotientLow,
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&QuotientHigh);
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UNREFERENCED_PARAMETER(Remainder); // TODO: Rounding
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TempResult.Mantissa = QuotientLow;
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if (QuotientHigh > 0ULL)
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{
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ULONG BitsToShift = 64 - CountLeadingZeros64(QuotientHigh);
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if (!State->FpuControl.Pm)
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{
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/* Raise the precision expection */
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State->FpuStatus.Pe = TRUE;
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return;
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}
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TempResult.Mantissa >>= BitsToShift;
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TempResult.Mantissa |= QuotientHigh << (64 - BitsToShift);
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Exponent += BitsToShift;
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// TODO: Rounding
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}
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if (Exponent < -FPU_REAL10_BIAS)
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{
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TempResult.Mantissa >>= -(Exponent + FPU_REAL10_BIAS);
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Exponent = -FPU_REAL10_BIAS;
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if ((TempResult.Mantissa == 0ULL) && !State->FpuControl.Um)
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{
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/* Raise the underflow exception */
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State->FpuStatus.Ue = TRUE;
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return;
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}
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// TODO: Rounding
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}
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TempResult.Exponent = (USHORT)(Exponent + FPU_REAL10_BIAS);
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/* Normalize the result */
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Fast486FpuNormalize(State, &TempResult);
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*Result = TempResult;
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}
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static inline VOID FASTCALL
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@ -853,10 +1006,86 @@ FAST486_OPCODE_HANDLER(Fast486FpuOpcodeD9)
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FPU_CHECK();
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#ifndef FAST486_NO_FPU
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// TODO: NOT IMPLEMENTED
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UNIMPLEMENTED;
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#else
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/* Do nothing */
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if (ModRegRm.Memory)
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{
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switch (ModRegRm.Register)
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{
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/* FLD */
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case 0:
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{
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ULONG Value;
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FAST486_FPU_DATA_REG MemoryData;
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if (!Fast486ReadModrmDwordOperands(State, &ModRegRm, NULL, &Value))
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{
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/* Exception occurred */
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return;
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}
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Fast486FpuFromSingleReal(State, Value, &MemoryData);
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Fast486FpuPush(State, &MemoryData);
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break;
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}
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/* FST */
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case 2:
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/* FSTP */
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case 3:
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{
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// TODO: NOT IMPLEMENTED
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UNIMPLEMENTED;
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break;
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}
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/* FLDENV */
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case 4:
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{
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// TODO: NOT IMPLEMENTED
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UNIMPLEMENTED;
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break;
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}
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/* FLDCW */
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case 5:
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{
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Fast486ReadModrmWordOperands(State, &ModRegRm, NULL, &State->FpuControl.Value);
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break;
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}
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/* FSTENV */
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case 6:
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{
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// TODO: NOT IMPLEMENTED
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UNIMPLEMENTED;
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break;
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}
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/* FSTCW */
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case 7:
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{
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Fast486WriteModrmWordOperands(State, &ModRegRm, FALSE, State->FpuControl.Value);
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break;
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}
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/* Invalid */
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default:
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{
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Fast486Exception(State, FAST486_EXCEPTION_UD);
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return;
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}
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}
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}
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else
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{
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// TODO: NOT IMPLEMENTED
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UNIMPLEMENTED;
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}
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#endif
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}
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@ -59,6 +59,7 @@
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#define FPU_IS_INFINITY(x) (FPU_IS_NAN(x) && ((x)->Mantissa == FPU_MANTISSA_HIGH_BIT))
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#define FPU_IS_POS_INF(x) (FPU_IS_INFINITY(x) && !(x)->Sign)
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#define FPU_IS_NEG_INF(x) (FPU_IS_INFINITY(x) && (x)->Sign)
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#define FPU_IS_INDEFINITE(x) (FPU_IS_NAN(x) && !FPU_IS_INFINITY(x))
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enum
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{
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