[comp.sys.atari.st] CO-Processors

so01@dmarum8.BITNET (Thomas Neser) (01/03/90)

Hello netters,
does anyone know something about the use of coprocessors with PC-emu-
lators? a) The co-processors in use with the atari 68000er b) The co-
processors in use with a ibm (8087,80387SX). My second questions is if
the procesors of atari are used by special atari-programs, for instance
statistical ones and which of the offered processors are any good. The
second is if these can be used with pc-emulators as ibm-coprocessors or
the same thing arround if ibm-processors can be used as well with the
atari. The last thing for today is if the blitterchip of the mega can be
built in a 1040er and if it makes emulation faster too or if there is
software arround which speeds up operation in work with atari and ibm-
emulation as well as co-processors and blitter-chip can. Think this is
enough for today and wish all of you a nice 1990. If you know something
of interest please email to so01@dmarum8.bitnet.
Thanks in advance
Thomas Neser

apratt@atari.UUCP (Allan Pratt) (01/12/90)

kar7481@cuphub.cup.edu (Dan Karbowsky;AtariEliteOfPghPa bbs412-384-5609) writes:
>I was VERY INTERESTED in attempting to tack a mc68881 co-processor onto
>my 1040.....I talked to ATARI-US and ATARI-UK: They couldn't tell me 
>ANYTHING and ATARI-US denied the '881s existance.

I can't imagine why they did that.

Atari has a product, the SFP004, which is a 68881 peripheral for a Mega.
It only works with Megas, not 1040s, which may have been the source
of the confusion.  It comes with a library (and source!) for linking
Alcyon C programs which use floating point so they use the 68881
if it's there, and use the old software routines if it's not.

Once you have this technical document and a 68881 chip, how do you
propose to weld the chip into your 1040?  It's a nontrivial
undertaking.  The SFP004 plugs into the internal Mega expansion bus. If
you do manage to weld a 68881 onto a 1040, please try to make sure it
addresses at the same place as the SFP004: the base address is $FFFA40.

============================================
Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt

Chris.Forker@newcastle.ac.uk (Chris Forker - Nav Arch-) (01/13/90)

In article <1946@atari.UUCP> apratt@atari.UUCP (Allan Pratt) writes:
>kar7481@cuphub.cup.edu (Dan Karbowsky;AtariEliteOfPghPa bbs412-384-5609) writes:
>>I was VERY INTERESTED in attempting to tack a mc68881 co-processor onto
>>my 1040.....I talked to ATARI-US and ATARI-UK: They couldn't tell me 
>>ANYTHING and ATARI-US denied the '881s existance.
>
>I can't imagine why they did that.
>
>Atari has a product, the SFP004, which is a 68881 peripheral for a Mega.
>It only works with Megas, not 1040s, which may have been the source
>of the confusion.  It comes with a library (and source!) for linking
>Alcyon C programs which use floating point so they use the 68881
>if it's there, and use the old software routines if it's not.
>
>============================================
>Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
>reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt

Allan, When I got the 68881 board for my Mega, I did not get a library
or source code. However, as I use Prospero's software I bought their
drivers.

You mention that the Alcyon C compiler uses the 68881 if it is there,
otherwise the software emulation. How does it manage this. With
Prospero's compilers, ( I use Fortran & Pascal ), the result will be a
bus error on machines with no 68881. Does TOS1.4 have some trap that I
can call from Fortan or Pascal which will indicate the presence of a
68881 ??

Thanks in advance

Chris....


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VBRANDT@DBNUAMA1.BITNET (01/15/90)

Hello all,

In Info-Atari16 Digest #40, mcsun!ukc!newcastle.ac.uk!tadhg!chris@uunet.uu.net
(Chris Forker - Nav  Arch-) said:

>You mention that the Alcyon C compiler uses the 68881 if it is there,
>otherwise the software emulation. How does it manage this. With
>Prospero's compilers, ( I use Fortran & Pascal ), the result will be a
>bus error on machines with no 68881. Does TOS1.4 have some trap that I
>can call from Fortan or Pascal which will indicate the presence of a
>68881 ??

No, there is no such trap.  The correct way to test for a 68881 is to redirect
the error handler, then try to reset the 68881.  If your program continues
normally, there is a 68881 present.  If the error handler is called, there is
none.  Then all you have to do is to reset the error handler.

The Alcyon compiler does not do any 68881 checking.  There simply is a library
provided that replaces the original software floating-point library.

If you need software that checks for an 68881 and runs unchanged on systems
with AND without FPU, check out Turbo C/ST by Borland.  It has that feature
built in, without the need to buy additional libraries (such as the Prospero
lib, which costs about as much as the entire Turbo C !!!)

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