$z = 1050000000000000; # may be int on systems with 64bit?
$x = Math::BigInt->new($z); ok ($x->bsstr(),'105e+13'); # not 1.03e+15?
-$z = 1e+129; # definitely a float
-$x = Math::BigInt->new($z); ok ($x->bsstr(),$z);
+if ($^O eq 'os390' || $^O eq 's390') { # non-IEEE
+ $z = 1e+75; # definitely a float
+ $x = Math::BigInt->new($z); ok ($x->bsstr(),$z);
+} else {
+ $z = 1e+129; # definitely a float
+ $x = Math::BigInt->new($z); ok ($x->bsstr(),$z);
+}
###############################################################################
# prime number tests, also test for **= and length()