In message <20011210133529.EYKY11472.femail13.sdc1.sfba.home.com@there>
Bryan C. Warnock <[EMAIL PROTECTED]> wrote:
> On Monday 10 December 2001 03:06 am, Tom Hughes wrote:
> > In message <20011210011601$[EMAIL PROTECTED]>
> >
> > Actually VAXes have perfectly ordinary endianness - it was PDPs that
> > had the middle endian layout.
>
> Who's got the 16 bittish little endian layout ("21436587")? (Perhaps it's
> wrong to categorize that as endianness.)
I always believed it to be one or more of the PDP machines - most unix
systems call it PDP endian in their header files. That said the jargon
file lists the PDP 10 as big endian and the PDP 11 as little endian,
and has this to say about the third form:
middle-endian adj.
Not big-endian or little-endian. Used of perverse byte orders such
as 3-4-1-2 or 2-1-4-3, occasionally found in the packed-decimal
formats of minicomputer manufacturers who shall remain nameless.
Certainly the VAX is a perfectly ordinary little endian system.
> > Presumably that's G_Floating that you're converting to/from for
> > the VAX rather than D_Floating?
>
> Yes. Is that going to be a problem? (The sum of programs I've written on
> a VAX can be represented with 1 digit. In base 2.)
Well VAXC defaults to using D_Floating for doubles but can be made
to use G_Floating instead with a switch to the compiler. I'm not sure
whether that makes it a problem or not.
> I've paper code for converting to and from D_Floating (for general data
> migration), but it's range is too restrictive for my liking for floating
> point constants inside of bytecode. If this is bumpkis, someone clue me
> in, por favor.
As you say the exponent is more restricted (it has the same size as
in F_Floating which is the single precision format) but the trade off
is that the mantissa is larger so you get greater precision at the
expense of less range.
Tom
--
Tom Hughes ([EMAIL PROTECTED])
http://www.compton.nu
