void ieee_floatt::align()
{
// NaN?
if(NaN_flag)
{
fraction=0;
exponent=0;
sign_flag=false;
return;
}
// do sign
if(fraction<0)
{
sign_flag=!sign_flag;
fraction=-fraction;
}
// zero?
if(fraction==0)
{
exponent=0;
return;
}
// 'usual case'
mp_integer f_power=power(2, spec.f);
mp_integer f_power_next=power(2, spec.f+1);
std::size_t lowPower2=fraction.floorPow2();
mp_integer exponent_offset=0;
if(lowPower2<spec.f) // too small
{
exponent_offset-=(spec.f-lowPower2);
assert(fraction*power(2, (spec.f-lowPower2))>=f_power);
assert(fraction*power(2, (spec.f-lowPower2))<f_power_next);
}
else if(lowPower2>spec.f) // too large
{
exponent_offset+=(lowPower2-spec.f);
assert(fraction/power(2, (lowPower2-spec.f))>=f_power);
assert(fraction/power(2, (lowPower2-spec.f))<f_power_next);
}
mp_integer biased_exponent=exponent+exponent_offset+spec.bias();
// exponent too large (infinity)?
if(biased_exponent>=spec.max_exponent())
{
// we need to consider the rounding mode here
switch(rounding_mode)
{
case UNKNOWN:
case NONDETERMINISTIC:
case ROUND_TO_EVEN:
infinity_flag=true;
break;
case ROUND_TO_MINUS_INF:
// the result of the rounding is never larger than the argument
if(sign_flag)
infinity_flag=true;
else
make_fltmax();
break;
case ROUND_TO_PLUS_INF:
// the result of the rounding is never smaller than the argument
if(sign_flag)
{
make_fltmax();
sign_flag=true; // restore sign
}
else
infinity_flag=true;
break;
case ROUND_TO_ZERO:
if(sign_flag)
{
make_fltmax();
sign_flag=true; // restore sign
}
else
make_fltmax(); // positive
break;
}
return; // done
}
else if(biased_exponent<=0) // exponent too small?
{
// produce a denormal (or zero)
mp_integer new_exponent=mp_integer(1)-spec.bias();
exponent_offset=new_exponent-exponent;
}
exponent+=exponent_offset;
if(exponent_offset>0)
{
divide_and_round(fraction, power(2, exponent_offset));
// rounding might make the fraction too big!
if(fraction==f_power_next)
{
fraction=f_power;
++exponent;
}
}
else if(exponent_offset<0)
fraction*=power(2, -exponent_offset);
if(fraction==0)
exponent=0;
}
void ieee_floatt::align()
{
// NaN?
if(NaN)
{
fraction=0;
exponent=0;
sign=false;
return;
}
// do sign
if(fraction<0)
{
sign=!sign;
fraction=-fraction;
}
// zero?
if(fraction==0)
{
exponent=0;
return;
}
// 'usual case'
mp_integer f_power=power(2, spec.f);
mp_integer f_power_next=power(2, spec.f+1);
mp_integer exponent_offset=0;
if(fraction<f_power) // too small?
{
mp_integer tmp_fraction=fraction;
while(tmp_fraction<f_power)
{
tmp_fraction*=2;
--exponent_offset;
}
}
else if(fraction>=f_power_next) // too big?
{
mp_integer tmp_fraction=fraction;
while(tmp_fraction>=f_power_next)
{
tmp_fraction/=2;
++exponent_offset;
}
}
mp_integer biased_exponent=exponent+exponent_offset+spec.bias();
// exponent too large (infinity)?
if(biased_exponent>=spec.max_exponent())
infinity=true;
else if(biased_exponent<=0) // exponent too small?
{
// produce a denormal (or zero)
mp_integer new_exponent=mp_integer(1)-spec.bias();
exponent_offset=new_exponent-exponent;
}
exponent+=exponent_offset;
if(exponent_offset>0)
{
divide_and_round(fraction, power(2, exponent_offset));
// rounding might make the fraction too big!
if(fraction==f_power_next)
{
fraction=f_power;
++exponent;
}
}
else if(exponent_offset<0)
fraction*=power(2, -exponent_offset);
if(fraction==0)
exponent=0;
}
