[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [avr-libc-dev] 64-bit doubles

From: Dave N6NZ
Subject: Re: [avr-libc-dev] 64-bit doubles
Date: Sat, 20 Dec 2008 22:27:02 -0800
User-agent: Thunderbird 1.5 (X11/20051201)

Ron Kreymborg wrote:
Isn't there some compiler infrastructure that would have to
happen also?
Yes, we need to have both the library support, as well as the compiler
support. The compiler work might be easier than the library work, but
this is just conjecture.


For the moment I am thinking of implementing fp doubles as the typedef
"longfp" in long longs.

Well, I learned something. I've never wanted long long's in my AVR code, so I never went looking for them :) So now I know they are there.

As Preston has mentioned, this would be outside the
compiler. They would have the IEEE format, ie 52-bit mantissa and 11-bit
exponent. Obviously not the most efficient but very testable.

Testable? Well.... yes and no :)

Yes, in that since you are choosing the IEEE format many machines will give you most of the expected results that you need, modulo a small amount of errata.

No, in that the test space is enormous. Even if you can get expected results easily, it still takes a lot of careful test design to select the stimulus effectively.



reply via email to

[Prev in Thread] Current Thread [Next in Thread]