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From: Frank LoPinto <flopinto@aisvt.bfg.com>
Subject: Re: Floating point emulation
Date: 1997/03/17
Message-ID: <332D6A4A.1B46@aisvt.bfg.com>#1/1
X-Deja-AN: 226200416
References: <3326F958.35AC@aisvt.bfg.com> <5g9a75$6nn@top.mitre.org>
Organization: BFGoodrich Aerospace
Newsgroups: comp.lang.ada
Date: 1997-03-17T00:00:00+00:00
List-Id: <comp.lang.ada>


Michael F Brenner wrote:

Frank LoPinto wrote:
>>I am using a DDC-I Ada 83 compiler that is hosted on a SunOS platform.
>>The compiler cross-compiles to an 80X86 target.

>>Where can I get a 80x87 math co-processor emulation package that I can
>>link into my application?
> 
> Is this an arbitrary restriction by an ivory tower? Or have you
> costed out the cost of upgrading the chip to have a floating point
> unit versus the cost of emulating floating point in software?

No this is not an Ivory Tower restriction, in fact it is very much a
"real world" restriction. 

I am using and embedded version of the 80186, formally the 80186EB. The
system in which this processor resides will be placed on a helicopter.
We do not have an FPU beacuse of weight and power consumption
restrictions placed on the total system. There is no room. What is more,
the hardware is done. I have no choices with regards to harware.

Formerly, I was using the old DOS based Janus Ada compiler with the
embedded toolkit, for the pre-production and development versions of the
flight software. It had a floating point emulator such that if I told
the linker that I did not have an FPU, it would simply link in the FPU
emulator. This compiler, however, can no longer be used because I now
have a table that is over 4k in size and this compiler can not handle
it.

Now I could go and buy a new compiler that has everything I need, but
our company already has a license for the DDC-I that I can use. But as I
said, this compiler does not have FPU emulation.

Now there are a number of things I COULD do, but all options cost time
or money. I would rather spend neither, or at least reduce them to a
minimum. Hence the question.

--Frank

Frank LoPinto
BFGoodrich Aerospace
Aircraft Integrated Systems
Vergennes, VT
flopinto@aisvt.bfg.com