"wobble" in Floating Point (LONG) (was Re: comp_t)

Chris Torek torek at elf.ee.lbl.gov
Sat May 25 13:52:11 AEST 1991


In article <9105180923.aa03879 at art-sy.detroit.mi.us>
chap at art-sy.detroit.mi.us (j chapman flack) writes:
>Of course, the AT&T folks just traded off wobble for storage size and
>dynamic range. ... Now if they put all of that thought into the DESIGN,
>why couldn't they have put some of it into the COMMENTS ??

The comp_t stuff appears in 32V Unix (the original VAX port, swapping-
only) and hence must date back to pre-V7 times.  (32V apparently split
off just slightly before the V7 release.)

What this means is that the `AT&T folks' referred to above were really
the original Bell Labs folks, and they were not known for verbosity.
The comment in 32V reads:

	/* "floating pt": 3 bits base 8 exp, 13 bits fraction */

which is sufficient to tip off whoever might work on the file that
there was something more to it; whoever was doing said work would then
be expected to figure this out for himself, or ask....
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 415 486 5427)
Berkeley, CA		Domain:	torek at ee.lbl.gov



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