CAS: log of large integers?

[Thomas_Sch]

(05-22-2015 07:01 PM)parisse Wrote:  It's in usual.cc, line 497

Code:


  ...
    gen a,b;
    if (abs_calc_mode(contextptr)==38 && has_evalf(e,a,1,contextptr))
      return log10(a,contextptr);
    if (is_algebraic_program(e,a,b))
      return symbolic(at_program,gen(makevecteur(a,0,log10(b,contextptr)),_SEQ__VECT));
  ...

calc_mode returns 38 inside the hp39gii and -38 inside a Prime (and 1 inside geogebra). You can check inside Xcas, by running calc_mode(38) or calc_mode(-38) instead of calc_mode(0). calc_mode is not available on the Prime.

I don't understand this above,
calc_mode does something return - but calc_mode is not available ?

And how does this help Joe's question ?