On Sat, 10 Mar 2012 18:35:28 +0000, John Rumm wrote:

On 10/03/2012 18:20, Huge wrote:
On 2012-03-10, Nick
wrote:
On Sat, 10 Mar 2012 17:48:20 +0000 (UTC), Jules Richardson
wrote:

On Sat, 10 Mar 2012 13:33:46 +0000, John Rumm wrote:
;-) Rather like talking with IMB mid range / mainframe types who
seem convinced that Assembler (note the capital A!) can only be
known to hallowed IBM programmers, and can't seem to get their heads
round the fact that every processor has a low level assembly
language...

Every? Depends on the definition of assembly language, I suppose - is
it the binary opcodes which form CPU instructions, or is it the
human- readable mnemonics which correspond to those opcodes?

I usually think of assembly language as the latter (that being what
people program at the low level using)....

So do I. I understood the other stuff to be machine code. But it's a
very long time since I played with any of those toys.

Better not mention microcode, then.

)

Unless into DIYing your own processors, there is less chance to play
with that though ;-)

I've had a couple of goes.

The first one was decades ago...my department had a Honeywell DDP-516
when I was an undergraduate (they were used a lot as node processors on
the ARPAnet). My final year project consisted of adding new boards and
rewiring the backplane to modify the effect of some instructions, and add
new ones. And I won an IEE prize!

Second one was a bit later - reverse engineering the microcode on an ICL
2900, then modifying the microcode to make up for a hardware design flaw
that ICL wouldn't admit to.



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