<a href="http://www.quadibloc.com/comp/cp0201.htm">http://www.quadibloc.com/comp/cp0201.htm</a><div><br></div><div>And yes, reading the description it's easy to see how a programmer could either be confused, or could be right ... but only in the context of the original machine.,,, making porting those parts of the code hard.</div>
<div><br></div><div>Of course, there are people who aren't trying to write portable code. They often live to regret it ;></div><div><br></div><div><br clear="all">Keith Bierman<br><a href="mailto:khbkhb@gmail.com">khbkhb@gmail.com</a><br>
kbiermank AIM<br>303 997 2749<br>
<br><br><div class="gmail_quote">On Tue, Mar 2, 2010 at 1:25 AM, N.M. Maclaren <span dir="ltr"><<a href="mailto:nmm1@cam.ac.uk">nmm1@cam.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
On Mar 1 2010, Bill Long wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Indeed, M77. I looked at the manual and found that, in 1980, M77 had the radical extension of A .op. B where op was and, or, xor, ... and A and B were numeric type variables, with the operations bitwise. Only 30 years ago. Maybe this idea needs a bit more time to mature. :)<br>
</blockquote>
<br>
Or rot down?<br>
<br>
It was a major nightmare - and I don't mean just for portability.<br>
Even with a single compiler for a single architecture, bit-flipping<br>
on REAL and the sign bit of integers is beyond the ability of almost<br>
all programmers. If I recall, those machines weren't twos complement,<br>
either, but I didn't use them directly.<br>
<br>
Restricting it to non-negative integers has worked in many languages,<br>
but with the ongoing problem of priority. A == B.OR.C has been a major<br>
gotcha in every language that I know of that has allowed it. Even using<br>
two operators for the two priorities (and, to some extent, functionality)<br>
helps only a little.<br>
<br>
And, yes, I do mean that porting CDC Fortran wasn't JUST a matter of<br>
changing its syntax - it was amazing how often one discovered that the<br>
original programmer had made an error with bit twiddling due to the<br>
above gotchas.<br>
<br>
Regards,<br>
Nick Maclaren.<br>
<br>
<br>
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</blockquote></div><br></div>