Re: integer representation in pari

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Fri, May 28, 2010 at 11:13:11AM -0400, Sam Steingold wrote:
> Hi,
> 
> On 5/27/10, Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr> wrote:
> >
> >  You can also check whether the C macro PARI_KERNEL_GMP is defined,
> >  but usually it is better to use int_W() to acces the mantissa.
> 
> thanks!
> can I also use int_W to access the mantissa of a t_REAL?
> (it never explicitly says that, but ...)

No you cannot. t_REAL mantissa is always in HIGH bytes first,
so this would not work with the GMP kernel. Note that
t_REAL mantissa is normalized (i.e. first bit is one).

Cheers,
Bill.