Re: HELP ! need to insert value in array !!

[atbowler@thinkage.on.ca (Alan Bowler)]

In article <dewar.868107828@merv> dewar@merv.cs.nyu.edu (Robert Dewar) writes:
>Mike said
>
>Sure, but why do you think those instructions where there (the ones to
>handle odd chunk sizes). The answer is that the motivation was precisely
>to allow convenient support of the 7 bit format. The use of these
>instructions for any other size was rare. What happened was that there
>was a requirement for supporting the 5 char/word format in the hardware,
>and the designers generalized it to any byte size (rememebr this was the
>hey day of extravagant CISC design).

Hardly.  The PDP-10 was a very orthogonal design, and compared to
modern systems that call themselves RISC, looks very spartan.  If you
compared it to contemporary systems like the PDP-8 or the CDC-6600
it does look "complex", but it was certainly simpler than the /360.
The PDP-10 had the major RISC attributes many (at least for the time)
identical general registers, fixed length instructions, and no
"indicator register".  (I'm stretching the point on the last a little
it did have overflow and carry bits, but no zero or negative
indicators.)  The 5 byte instructions (load byte, store byte,
load next byte, store next byte and adjust byte pointer were certainly
much simpler than floating square root, floating sine etc that you find
on systems marketed as "RISC" today.

It was the PDP-11 that introduced those complex variable length addressing
modes, and the heyday of CISC only followed that great success.