[avr-libc-dev] Re: Request for cbrt() and strdup to be added to libc

[Andy H]

Here are some generic version that can be used as starter.
I'm sure someone can trim them up a bit - or even convert to asm.

Best version depends on how we built existing maths  functions.

double cbrt(const double x)

{
return pow(x,1.0/3.0);
}

double cbrt(const double xx)
{
   double x= xx;
   if  (x==0.0) /* log will fail, but answer is easy */
      return 0.0;
   else if  (x>0.0)
       return(exp(log(x)/3.0));
   else
   x= -x;
      return(exp(log(x)/3.0));
  
}



char *  strdup( const char *str)
{
       unsigned int len;
       char *copy;
       len = strlen(str) + 1;
       copy = malloc(len);
       if (!copy)
               return (copy);
       memcpy(copy, str, len);
       return (copy);
}
Andy

Weddington, Eric wrote:
> I don't see any problem with adding these to avr-libc, other than a lack
> of an implementation. ;-)
>
> In general, we try to do as much hand-coded assembly as possible, except
> for very large functions (e.g. printf and friends) where it would be
> difficult to do so.
>
> Eric 
>
>   
> > -----Original Message-----
> > From: Andy H [mailto:address@hidden 
> > Sent: Sunday, June 22, 2008 10:35 AM
> > To: Weddington, Eric; Joerg Wunsch; Dmitry K.
> > Subject: Request for cbrt() and strdup to be added to libc
> >
> > It seems gcc testsuite assumes presence of widely available 
> > strdup() and 
> > cbrt() functions.
> >
> > strdup is a derivative of malloc
> > cbrt is cubic root x^(1/3)
> >
> > I dont think it would be any hardship to add these to avr library.
> >
> > Can this be done?
> >
> > best regards
> >
> >
> >
> >
> >