IA32: printing FP register variables

[Joern Rennecke]

> I would suggest that we may use a "negative" ST value.  The debugger can
> always know the depth of the stack from reading the status registers, so
> saying that something was in ST(7) could be interpreted as the top-most
> stack item, ST(6) as one below that, and so on.  As long as the relative
> position of items on the stack didn't change (this var is always 2 from the
> top), this should be OK.

I think you get more stable position designations by considering the
position relative to the bottom of the stack.