Single/double precision equality question

[Daniel J Sebald]

Should the following equality behavior be explained in "help =="?

> > format bit
> > single(0.1)
ans = 0011111110111001100110011001100110100000000000000000000000000000
> > double(0.1)
ans = 0011111110111001100110011001100110011001100110011001100110011010
> > single(0.1) == double(0.1)
ans = 0011111111110000000000000000000000000000000000000000000000000000

I guess I'm OK with it.  The test demotes the double to a single.  Try:

> > double(single(0.1)) == double(0.1)
ans = 0000000000000000000000000000000000000000000000000000000000000000

However, the demoting rule doesn't hold true for all classes.  Try:

> > format
> > v1 = pi;
> > v2 = int8(v1);
> > v1 == v2
ans = 0

Whatever the case, it probably would be good to have this documented for 
the user.  Perhaps it is, but I don't know where to look beyond "help ." 
and "help ==".

Dan