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From: bcw@rti.UUCP (Bruce Wright)
Newsgroups: comp.arch,comp.misc,comp.lang.misc,comp.protocols.misc
Subject: Re: "big endian" and "little endian" - first usage for computer
Summary: Another view on number formats
Message-ID: <2695@rti.UUCP>
Date: 6 Jan 89 06:38:04 GMT
References: <2766@cbnews.ATT.COM> <10147@well.UUCP> <13045@cup.portal.com> <20264@ames.arc.nasa.gov>
Organization: Research Triangle Institute, RTP, NC
Lines: 33

In article <20264@ames.arc.nasa.gov>, lamaster@ames.arc.nasa.gov (Hugh LaMaster) writes:
> In article <13045@cup.portal.com> bcase@cup.portal.com (Brian bcase Case) writes:
> 
> >Since it forces inefficiency, little-endian is for CISCs.  :-) :-)
> 
> All this was covered about 2 years ago on this group: the conclusion then
> was that little-endian had a small advantage on tiny machines (e.g. 8008
> class and slower) needing to do BCD arithmetic, big endian machines have
> the "advantage" that it is easier to read dumps, and there are no other
> significant differences.  VAXes, of course, are not consistent little-
> endian or big-endian, but then, we are not supposed to have to read dumps
> anymore anyway, remember ?  :-)
> 
My immediate thought on seeing the VAX instruction set when it first came
out was that by making the byte order "little endian" it allowed something
like a Fortran compiler to take a statement like:

	call sub (1)

and pass a number to it (a longword - 4 bytes) which would be interpreted
correctly whether the receiving formal parameter was a byte, a word (2 bytes),
or a longword (4 bytes).  This is not possible in a "big endian" machine -
you have to know how many bytes of high order 0's to write before you get to
the low order byte.  Considering that the Fortran of the day had no way to
declare the formal parameters for subroutines, and the importance of
Fortran in the early days of the VAX (and the fact that the VAX was built
with a great deal of input from the software guys), could this be the REAL
motivation for "little endian"?

Of course the fact I even thought of the possibility of such a trick
probably shows I'm just an old Fortrash hacker ...

						Bruce C. Wright