Abnormal normalizations?

[John R Levine]

|I am told that there are actual computers like this.  Thus, some bits can be
|"scraped off" when a quantity represented in a register passes through a
|memory "knothole", and naturally the skinny value may not compare equal to
|the original wider value.

No kidding -- I'm typing this on one of them, a 486.

This is not quite as capriciously brain damaged as it seems.  The '87
has 80 bit registers and only one FP format in a register, extended.
When you store something to memory, you can store it as float,
double, or extended, and the shorter formats are widened to extended
when you load them.  So even if you are doing arithmetic on floats,
the '87 does you a favor and internally does the work on extendeds,
turning them back to floats only when you save them.

I am not enough of a numerical analyst to say whether this is a good idea
or not, but a few years back I listened to a most interesting talk given
by one of the guys who designed the 8087, and it was clear that this
deecisions was not made arbitrarily.
-- 
Regards,
John Levine, johnlaiecc.com, {spdcc|ima|world}!iecc!johnl