Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!amdcad!sun!pitstop!sundc!seismo!uunet!mcvax!ukc!reading!minster!john
From: john@minster.york.ac.uk
Newsgroups: comp.os.minix
Subject: Floating point for Minix cc(1)
Message-ID: <595768844.26413@minster.york.ac.uk>
Date: 17 Nov 88 11:20:44 GMT
Organization: Department of Computer Science, University of York, England
Lines: 33

Will the Minix cc(1) ever fully implement floating point types? For
those of you who havn't tried compiling a program containing types
float and/or double, one gets the compiler message (PC Minix 1.2):

	warning: dummy floating point constant(s)

An inspection of the code produced shows that all-zero bit constants
are output, but that plausible-looking C library subroutine calls are
produced for floating point operations. An examination of the C library
code shows that routine stubs are present.

This is not news to many Minix enthusiasts out there, I know. Is
there a good reason *not* to add floating point support? (I know only
of Dr. Tanenbaum's "I havn't used a number bigger than 32767 in years"
argument - which, I feel, misses the point, somewhat).

I believe that there is little point in adding all-software floating point
support (for the PC, at least), when all it would take is for the
owners of the cc(1) code generator to alter it to produce 80X87 (IEEE
standard) constants, and for someone to flesh out the C library routines
to use 80X87 operations. There wouldn't even be the need to alter asld(1)
to incorporate 80X87 operation mnemonics (need they be used anywhere
other than in the library routines?) - as `.byte' directives would do.
Naturally, the library would have to check (once) for the presence of the
floating point hardware.

-------------------------------------------------------------------------------
John A. Murdie                     "The End of our Foundation is the knowledge
Dept. of Comp. Sci.                 of Causes, and secret motions of things;
University of York                  and the enlarging of the bounds of
England                             Human Empire, to the effecting of all
                                    things possible"
ukc!minster!john                    Francis Bacon, "The New Atlantis", 1627