<div dir="ltr"><div><div><div><div><div><div><div>Any more, with the optimizing compilers we have today, it doesn't make much sense to use machine language for most program development.<br></div>1. The compilers often produce better code that the average programmer would produce, and often better than a good one would produce. The optimizer doesn't care about making readable code, so it can do aggressive things to the code that a human wouldn't wnt to. LLVM is even working with optimizations across compilation units.<br></div>2. Portability issues. If you write in machine language on a VAX/VMS, that is all it will run on. Porting it to VAX/Unix<br></div> might be possible, put with the differing system interfaces, not easy.<br></div>3. Ease of development. Developing in a higher level language is usually faster than in a machine language environment. It is also often easier for others to quickly comprehend. One line in high level code, "a=b*c+d*e", verses numerous lines of assembly code.<br></div><div>4. What do you do if your platform suddenly gets new opcodes. This happened with the Alpha, Intel x86, and many others. Update your code, or leave it the same so it can still run on older hardware?<br></div><br></div>There are some places where hand-coded machine code is useful, but its use isn't as necessary as it used to be. It can be interesting to know some of the details.<br></div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Feb 15, 2016 at 1:47 PM, Mark Wickens <span dir="ltr"><<a href="mailto:mark@wickensonline.co.uk" target="_blank">mark@wickensonline.co.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<td>[Simh] Assembler programming under Unix - was VAX/VMS</td>
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<th align="RIGHT" nowrap valign="BASELINE">Date: </th>
<td>Mon, 15 Feb 2016 20:46:46 +0000</td>
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<th align="RIGHT" nowrap valign="BASELINE">From: </th>
<td>Mark Wickens <a href="mailto:mark@wickensonline.co.uk" target="_blank"><mark@wickensonline.co.uk></a></td>
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<th align="RIGHT" nowrap valign="BASELINE">To: </th>
<td>Clem Cole <a href="mailto:clemc@ccc.com" target="_blank"><clemc@ccc.com></a></td>
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On a related note,<br>
<br>
Programming in assembly language for modern Unix always seemed a
bit haphazard to me and the assemblers a bit non-standard and
poorly documented, but maybe I have a skewed view.<br>
<br>
Does programming the VAX under Unix fair any better in terms of
assembler quality and documentation?<br>
I appreciate that assembler programming for Unix may be frowned
upon given the C heritage.<br>
<br>
Feel free to tell me I'm wrong... about anything!<br>
<br>
Regards, Mark.<br>
<br>
<div>On 15/02/16 17:21, Clem Cole wrote:<br>
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<div dir="ltr">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">below...</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Feb 15, 2016 at 12:14 PM,
Will Senn <span dir="ltr"><<a href="mailto:will.senn@gmail.com" target="_blank">will.senn@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">What
is a good source to learn a bit about VAX/VMS and the
relationship of the VAX and PDP-11 architectures and
programming differences?</blockquote>
<div><br>
</div>
<div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">
Hmm probably this list....😈</div>
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<div><br>
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<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> I
looked at the Wikipedia article. I'm not sure it is
entirely accurate and it is sketchy on particulars.<br>
</blockquote>
<div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Which
one - the VAX/VMS article?</div>
<br>
</div>
<div><br>
</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <br>
Also, can the Vax run v6 or v7?<br>
</blockquote>
<div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">32V is
the original V7 to the 780.</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Nothing
there much that you will learn that you can not learn
from V7 on the 11/70. It does have a newer compiler.</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif">If you
want to see UNIX on an 780, start with BSD 4.1</div>
<br>
</div>
<div><br>
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<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <br>
Thanks,<br>
<br>
Will<br>
</blockquote>
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