Making Math Programs That Run on All Macs
 
Microbytes Daily News Service
Copyright (c) 1989, McGraw-Hill, Inc.
A small West German software company has developed a program that
emulates Motorola 68020 and 68881 instructions on a Macintosh SE,
Plus, or Portable, systems that use the 68000 CPU. Called Xmath,
the package allows programs that are optimized to run on the Mac
II to also run without modification on the lower-end Macintoshes.
This can be done despite the fact that the low-end Macs use the
Motorola 68000 processor and do not have the 68881 math
coprocessor. The company, called d'ART Computer, is licensing the
program only to software developers and not to end users.
 
According to d'ART Computer president Wilfried Beeck, the major
benefit of Xmath is that it allows Mac software developers to
compile one single version of their products that will run on all
Mac computers. Without Xmath, according to Beeck, programs that
make direct calls to the 68881 math coprocessor will not run on
the lower-end Macs. To run on the 68000-based machines, separate
versions of the program must be compiled that use the Standard
Apple Numerics Environment (SANE), which emulates the 68881 but
does not allow the use of direct 68881 calls.
 
d'ART Computer claims that Xmath performs floating-point
operations on the low-end Macintoshes up to 10 times faster than
using equivalent SANE operations. It also allows developers to
optimize their software for the Mac II without having to worry
about compatibility with the other end of the Mac product line.
According to Beeck, many CAD and spreadsheet developers offer
separate versions of their software for the low- and high-end
Macs (Wingz, Mathematica, VersaCad are examples). With Xmath, a
single version optimized for the 68881 will work on all machines.
Beeck says that the software works just as well on the 68882 and
68030 processors used on the Mac IIx and IIcx, since the
instruction sets are compatible. However, Xmath does not emulate
the built-in paged memory management unit (PMMU) of the 68030.
This is not an issue with the current version of the Mac
operating system, which does not take advantage of the PMMU.
 
Several "major software vendors" have licensed Xmath and will
integrate it into future versions of their software, Beeck said.
Beeck claims that over 50 percent of the numeric-intensive
applications shown at the next MacWorld Expo will be using Xmath.
The only competition comes from Radius SANE and Bravo's SPAMM,
which both try to optimize SANE operations, but do not support
direct 68881 calls, he said.
 
Contact: d'ART Computer, Fleethoern 23, 2300 Kiel 1, West
Germany; phone (49) 431/970066 or 431/92323; fax (49)
431/94423.
 
                              --- BYTEWeek Staff
 
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