ASM 86 file for use with GNAT for MS-DOS

ASM 86 file for use with GNAT for MS-DOS

[Debs Wisbey]

Dear All,

I am porting some Ada code from the old Alsys compiler to the new GNAT
3.10p for MS-DOS compiler, and some of the coding uses a file which
has been written for assembly using ASM 86(I think).

I have the old *.obj file that was generated and wondered if it is
possible for me to link this file using GNAT 3.10p for MS-DOS?  If
not, can anyone suggest an alternative assembler, with good
documentation, that I could use to create a new object file?

I have very little knowledge of Assembly language (about 3 tutorials
at uni) so any help would be greatly appreciated.

Thank you for any help that you can give me,
Debs.

Re: ASM 86 file for use with GNAT for MS-DOS

[Vinzent Hoefler]

Debs Wisbey wrote:

>I have the old *.obj file that was generated and wondered if it is
>possible for me to link this file using GNAT 3.10p for MS-DOS?

Probably not. I doubt that Alsys uses the same format (COFF), if it is
32-bit yet at all.

>  If
>not, can anyone suggest an alternative assembler, with good
>documentation, that I could use to create a new object file?

You could try NASM at <URL:http://nasm.sourceforge.net>.

But be warned: even if these sources assemble some day, that doesn't
mean, that everything will work as expected. I suspect your old files
assume a 16-bit-model and GNAT is 32-bit, so depending on what exactly
the assembly files are for, that can make a huge difference.

The better approach would be to rewrite it...


Vinzent.

Re: ASM 86 file for use with GNAT for MS-DOS

[Randy Brukardt]

"Vinzent Hoefler" <ada.rocks@jlfencey.com> wrote in message
news:bgo6af$qapgn$1@ID-175126.news.uni-berlin.de...
Debs Wisbey wrote:

>>I have the old *.obj file that was generated and wondered if it is
>>possible for me to link this file using GNAT 3.10p for MS-DOS?

>Probably not. I doubt that Alsys uses the same format (COFF), if it is
>32-bit yet at all.

...
>But be warned: even if these sources assemble some day, that doesn't
>mean, that everything will work as expected. I suspect your old files
>assume a 16-bit-model and GNAT is 32-bit, so depending on what exactly
>the assembly files are for, that can make a huge difference.

>The better approach would be to rewrite it...

Right. If that is 16-bit assembly code, there is no chance that it will work
with a 32-bit compiler like GNAT.

An option would be to port it to Janus/Ada 83 instead, we still support the
16-bit version of that.

Otherwise, you'll have to get rid of the assembler code, replacing it by Ada
(hopefully) and possibly in-line assembler. You may need to find someone who
understands 8086 assembler to do that. (I may be available. :-)

                               Randy.

Re: ASM 86 file for use with GNAT for MS-DOS

[Ed Falis]

You should definitely check the assembly code to see whether it's using
segmented addresses, though.  The Alsys DOS compiler had a version as
early as '87 (roughly) that used the 80386 flat 32 bit address space. 
That would probably be a V4.x and should be labelled as for the 80386
(as opposed to 80286).

- Ed