Daniel Kochmański daniel at turtleware.eu
Fri Sep 4 18:14:21 UTC 2015

Raymond Toy writes:

>>>>>> "Daniel" == Daniel Kochma <Daniel> writes:
>     Daniel> Also, we'll have to define such infinity for each architecture
>     Daniel> separately, depending on the endianess?
>     >> 
>     >> Yes, probably. But you only need to set up MSB/LSB to get the right
>     >> thing. I think.  At least that's how fdlibm works and how cmucl
>     >> produces it's infinities (in C code).  Of course in Lisp, cmucl has
>     >> special builtins to create floats from bits appropriately.  Perhaps
>     >> ecl can do something similar. (But there are separate implementations
>     >> for each architecture.)
>     Daniel> I'd rather avoid that. ECL runs now on number of architectures I have no
>     Daniel> access too.
> I suspect every arch you care about has 32 (or 64) bit words, and all
> floats are IEEE.
> So, perhaps it would be easier to create them as you mentioned
> earlier via 1/0 and 0/0 or related expressions.
> This requires that you be able to turn off exceptions in C, but ecl
> can probably already do that.

I'll fallback to it, if C99 extension isn't present, that is:

#ifndef INFINITY
#define INFINITY (1.0 / 0.0)

#ifndef NAN
#define NAN (0.0 / 0.0)

Thanks for help.

Best regards,

Daniel Kochmański | Poznań, Poland
;; aka jackdaniel

"Be the change that you wish to see in the world." - Mahatma Gandhi

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