all computations to be done in extended precision?



Hello,
 Is there a declaration at the beginning of a program to have all 
calculations done in extended precision?

It's a little cumbersome to do, e.g.
%i39) fpprec: 50;
Evaluation took 0.00 seconds (0.00 elapsed) using 0 bytes.
(%o39)                                50
(%i40) f(x,y):= bfloat(x)^2 + bfloat(y)^2;
Evaluation took 0.00 seconds (0.00 elapsed) using 0 bytes.
                                       2            2
(%o40)                f(x, y) := bfloat (x) + bfloat (y)
(%i41) f(2.1,3.2);
Evaluation took 0.00 seconds (0.00 elapsed) using 0 bytes.
(%o41)       1.4650000000000001509903313490212934419184329654106b1

TIA,
 -sen