Re: [Chicken-users] 32 bit integers?

[John Cowan]

Dan Muresan scripsit:

> Actually, I haven't found the 31-bit format documented anywhere (maybe I 
> missed it). I thought that at least normal C int's would always fit in a 
> fixnum. It was an unpleasant surprise to see an expression like (logior 
> flags ...) fail, when "flags" was promoted to a flonum.

As a format, it's documented at
http://galinha.ucpel.tche.br:8080/Data%20representation .  The reason
for reserving one bit is so that fixnums need not be allocated in full
words ("boxed"), but can be mixed with pointers, characters, #t, #f,
(), and (void).  This is typical of Lisp systems.

I have added a warning at
http://galinha.ucpel.tche.br:8080//Deviations%20from%20the%20standard .

> I don't see a way to hack these using flonums. Bignums would solve the 
> problem but they're slow.

You pays your money and you takes your choice.

One thing I found irritating is that the FFI does not support the
types of the numbers egg.  In interfacing Chicken and Q, both of
which use GMP, I found that the only reliable way to pass a
bignum from one system to the other was as a string.

-- 
In politics, obedience and support      John Cowan <address@hidden>
are the same thing.  --Hannah Arendt    http://www.ccil.org/~cowan