Re: [boost] Optimized portable isnan, isfinite, fpclassify etc

From: Johan Råde (rade_at_[hidden])
Date: 2006-12-08 07:14:15

Boris Gubenko wrote:

> /float=ieee is necessary on AlphaVMS because on this platform, the
> default floating point mode is G_FLOAT: one of so called VAX FP modes.

The VAX FP modes do not support denormals, infinity and NaN, right?

If that is the case, then we can implement fpclassify as follows:

   return x ? FP_NORMAL : FP_ZERO;

We just need to able to detect the VAX FP modes at compile time.

--Johan