TInt RealToRatio(SRatio& aRatio, const TRealX& aReal)
{
aRatio.iSpare1 = 0;
aRatio.iSpare2 = 0;
if (aReal.iSign || aReal.IsZero() || aReal.IsNaN())
{
aRatio.iM = 0;
aRatio.iX = 0;
return (aReal.IsZero()) ? KErrNone : KErrNotSupported;
}
TRealX rx(aReal);
TRealX rr(rx);
rr.iExp -= 32;
rr.iMantLo = 0;
rr.iMantHi = 0x80000000u;
rx += rr; // rounding
TInt exp = rx.iExp - 32767 - 31;
if (exp < -32768)
{
aRatio.iM = 0;
aRatio.iX = 0;
return KErrUnderflow;
}
if (exp > 32767)
{
aRatio.iM = 0xffffffffu;
aRatio.iX = 32767;
return KErrOverflow;
}
aRatio.iM = rx.iMantHi;
aRatio.iX = (TInt16)exp;
return KErrNone;
}
TInt RatioMult(const SRatio& aRatio, TUint32& aInt32)
{
TRealX rx;
TInt r = RatioToReal(rx, aRatio);
if (r != KErrNone)
return r;
r = rx.MultEq(TRealX((TUint)aInt32));
if (r != KErrNone)
return r;
if (rx.IsZero())
{
aInt32 = 0;
return KErrNone;
}
rx.AddEq(TRealX(0.5));
if (rx<TRealX(1))
{
aInt32 = 0;
return KErrUnderflow;
}
if (rx.iExp > 32767+31)
{
aInt32 = ~0u;
return KErrOverflow;
}
aInt32 = rx.operator TUint();
return KErrNone;
}
EXPORT_C TInt Math::Sqrt(TReal& aTrg,const TReal &aSrc)
/**
Calculates the square root of a number.
@param aTrg A reference containing the result.
@param aSrc The number whose square-root is required.
@return KErrNone if successful, otherwise another of
the system-wide error codes.
*/
//
// Fast sqrt routine. See Software manual by W.J.Cody & W.Waite Chapter 4.
//
{
const TRealX& KConstA=*(const TRealX*)KConstAdata;
const TRealX& KConstB=*(const TRealX*)KConstBdata;
const TRealX& Sqr2Inv=*(const TRealX*)Sqr2Invdata;
TRealX x;
TInt r=x.Set(aSrc);
if (x.IsZero())
{
aTrg=aSrc;
return(KErrNone);
}
if (r==KErrArgument || x.iSign&1)
{
SetNaN(aTrg);
return(KErrArgument);
}
if (r==KErrOverflow) // positive infinity
{
aTrg=aSrc;
return(r);
}
TInt n=x.iExp-0x7FFE;
x.iExp=0x7FFE;
TRealX y=KConstB*x+KConstA;
y=y+(x/y);
y.iExp--;
y=y+(x/y);
y.iExp--;
y=y+(x/y);
y.iExp--;
if (n&1)
{
y*=Sqr2Inv;
n++;
}
y.iExp=TUint16(TInt(y.iExp)+(n>>1));
return y.GetTReal(aTrg);
}
