Microport System V/AT Assembly Language not documented

[David Messer]

In article <750 at cgch.UUCP> whna at cgcha.uucp (Heinz Naef) writes:
 >The assembly language processed by the as(1) command of Microport System V/AT
 >has a completely different semantics, different instruction mnemonics and a
 >different assembler control (macro) language than usual assemblers for the
 >80x86 personal computers.

It's pretty close to PDP-11 assembler though... :-)

 >When writing a device driver at the lowest level (i. e. not on top of another
 >device driver) then there is a need to develop certain parts in assembly
 >language. With the documentation supplied by Microport for the System V/AT
 >program development and runtime system, it is *impossible* to even attempt to
 >write a minimum assembler program. Compared to the excellent documentation of
 >the linkkit, it is strange that there is no chapter on usage of the assembler
 >and on coding guidelines.

It is difficult, but not quite impossible.  I wrote a driver for the
IBM joystick port that incorporated a small assembly language routine
to access the hardware.  (It is highly timing dependent.)

What I did was write a C program that did approximatly what I wanted and
generated an assembly language version using the C-compiler.  (I.e.
the command "cc -S file.c" produces file.s)  I then hacked this file
to do what I wanted.  I posted this driver a year or so ago, but if
there is interest, I'll post it again.

I am curious as to what you are doing that requires assembly-language.
Unless you have extreme timing or efficiency requirements, there isn't
very much that you can't do in C.


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