ready-made Mac FP emulators?

[Mike Meissner]

| 
| I translated one from Motorola assembler to Sun assembler ten years ago
| to support the Sun-3; then we decided not to use it, and it probably wasn't
| freeware to begin with.    What does GCC use for software floating point
| on 68k systems?

The 68k port provides a set of tailored fp routines for use with
-msoft-float, when configured for an embedded 68k system or with
VxWorks.

There is also the file floatlib.c that is in the GCC releases that
provides basic floating point emulation from which the 68k floating
point was taken from.  Here is the header of that file.

/*
** libgcc support for software floating point.
** Copyright (C) 1991 by Pipeline Associates, Inc.  All rights reserved.
** Permission is granted to do *anything* you want with this file,
** commercial or otherwise, provided this message remains intact.  So there!
** I would appreciate receiving any updates/patches/changes that anyone
** makes, and am willing to be the repository for said changes (am I
** making a big mistake?).

Warning! Only single-precision is actually implemented.  This file
won't really be much use until double-precision is supported.

However, once that is done, this file might eventually become a
replacement for libgcc1.c.  It might also make possible
cross-compilation for an IEEE target machine from a non-IEEE
host such as a VAX.

If you'd like to work on completing this, please talk to rmsagnu.ai.mit.edu.


**
** Pat Wood
** Pipeline Associates, Inc.
** pipeline!phwamotown.com or
** sun!pipeline!phw or
** uunet!motown!pipeline!phw
**
** 05/01/91 -- V1.0 -- first release to gcc mailing lists
** 05/04/91 -- V1.1 -- added float and double prototypes and return values
**                  -- fixed problems with adding and subtracting zero
**                  -- fixed rounding in truncdfsf2
**                  -- fixed SWAP define and tested on 386
*/

/*
** The following are routines that replace the libgcc soft floating point
** routines that are called automatically when -msoft-float is selected.
** The support single and double precision IEEE format, with provisions
** for byte-swapped machines (tested on 386).  Some of the double-precision
** routines work at full precision, but most of the hard ones simply punt
** and call the single precision routines, producing a loss of accuracy.
** long long support is not assumed or included.
** Overall accuracy is close to IEEE (actually 68882) for single-precision
** arithmetic.  I think there may still be a 1 in 1000 chance of a bit
** being rounded the wrong way during a multiply.  I'm not fussy enough to
** bother with it, but if anyone is, knock yourself out.
**
** Efficiency has only been addressed where it was obvious that something
** would make a big difference.  Anyone who wants to do this right for
** best speed should go in and rewrite in assembler.
**
** I have tested this only on a 68030 workstation and 386/ix integrated
** in with -msoft-float.
*/

-- 
Michael Meissner
Cygnus Support (East Coast), 48 Grove Street, Somerville, MA 02144, USA
meissneracygnus.com,	617-629-3016 (office),	617-629-3010 (fax)