Graphics Reference
In-Depth Information
// half-float Infs will be converted to a single-
// precision Inf
exp = FLOAT_MAX_BIASED_EXP;
if (mantissa)
mantissa = (1 << 23) − 1; // set all bits to
// indicate a NaN
}
else if (exp == 0x0)
{
// convert half-float zero/denorm to single-precision
// value
if (mantissa)
{
mantissa <<= 1;
exp = HALF_FLOAT_MIN_BIASED_EXP_AS_SINGLE_FP_EXP;
// check for leading 1 in denorm mantissa
while ((mantissa & (1 << 10)) == 0)
{
// for every leading 0, decrement single-
// precision exponent by 1
// and shift half-float mantissa value to the
// left mantissa <<= 1;
exp −= (1 << 23);
}
// clamp the mantissa to 10 bits
mantissa &= ((I << 10) − 1);
// shift left to generate single-precision mantissa
// of 23-bits mantissa <<= 13;
}
}
else
{
// shift left to generate single-precision mantissa of
// 23-bits mantissa <<= 13;
// generate single-precision biased exponent value
exp = (exp << 13) +
HALF_FLOAT_MIN_BIASED_EXP_AS_SINGLE_FP_EXP;
}
f = (sign << 31) | exp | mantissa;
return *((float *)&f);
}
