float eval of sin and cos integrals?

I am getting an error message when evaluating
sin and cosine integral functions
expintegral_si(x) and expintegral_ci(x)
for largish args:
---------------------------------
Maxima 5.25.1 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (a.k.a. GCL)


(%i1) [expintegral_si(100.0),expintegral_ci(100.0)];

(%o1) [3.8412020891467011E+24,3.3074885133765204E+23]

(%i2) expintegral_si(1000.0);

expintegral_e: series failed.
 -- an error. To debug this try: debugmode(true);

(%i3) expintegral_ci(1000.0);

expintegral_e: series failed.
 -- an error. To debug this try: debugmode(true);

(%i4)
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Ted Woollett