New Software Lets Low-End Macs Run Mac II Programs
 
Microbytes Daily News Service
Copyright (c) 1989, McGraw-Hill, Inc.
New software from a West German company emulates Motorola 68020
and 68881 instructions on a Macintosh SE, Plus, or Portable, thus
bringing Mac II programs to those machines. Called Xmath, the
package allows programs designed to run only on the Mac II to
also run without modification on the lower-end Macs, which are
based on the Motorola 68000 processor and do not have the 68881
math coprocessor. The company, called d'ART Computer, is
distributing the program only to software developers and not to
end users.
 
The major benefit of Xmath, according to d'ART president Wilfried
Beeck, 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 coprocessor will not run on the low-end
Macs. To run on the 68000-based Macs, 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 claims that Xmath performs floating-point operations on the
low-end Macs 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 lower end of the Mac product line, the company says.
 
Many CAD and spreadsheet developers offer separate versions of
their software for the low- and high-end Macs (Wingz,
Mathematica, VersaCad are examples), Beeck says. 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, according to
Beeck. He claims that over 50% of the numeric-intensive
applications shown at the next MacWorld 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, Beeck says.
 
Xmath is available only on a licensed or royalty basis from
d'ART.
 
Contact: d'ART Computer, Fleethoern 23, 2300 Kiel 1, West
Germany; phone (49) 431/970066 or 431/92323; fax (49)431/94423.
 
                              --- Nick Baran
 
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