+long double:
+ drop ld128 support? and move ldshape union to arch/
+ (at least rename ieeel2 union and use the same union in all *l.c)
+volatile fix:
+ -ffloat-store or -fexcess-precision=standard probably fixes most volatile issues (and strict_assign)
+ volatile const may need different treatment
+rounding functions:
+ floor, ceil.. probably can be improved
+math.h:
+ nan 0/0 raises invalid
+ signbit >>63 or !!
+exceptions:
+ uniform inexact/invalid exception raising:
+ (int)x == 0 and huge+x > 0 are used
+ (unreachable code is not commented and hard to follow)
+log2:
+ dekker vs long double arithmetics