🚀 go-pugleaf

In article <4918@ganymede.inmos.co.uk>, malc@bilbo (Malcolm Boffey) writes:
>This is in response to queries about undocumented instructions for loading and
>storing the D, E, S registers.
>
>In addition to the published registers :- A, B, C, I, W, queue pointers etc,
>there are a few (D, E) that are used ...
>	There are one or two other instructions that are used for testing, none
>of them terribly usefull or interesting. Also, it is more or less a certainty
>that they will be discontinued in future transputers, or at least change their
>function significantly.

> Malcolm Boffey, Transputer Group, Inmos.   | Inmos Ltd,

This is fascinating. Over in comp.sys.mac there is continual screaming
and shouting and wailing and gnashing of teeth over numerous
violations of the interface guidelines. For example, some of the good
ol' MicroSoft products only work if you run them first (they use the
top 8 bits of the address space for tags), there are programs which
only drive particular versions of some of the printers, there are
drawing programs which reference screen memory directly (and hence
break on the newer machines), and so on. Despite Apple documenting the
programming interface for the Mac, and giving (admittedly pricey)
developer technical support, and not documenting anything lower
down, hackers still turn out *commercial products* like this.

So, I'm surprised that someone from Inmos will quite happily chat away
about undocumented features of the Transputer. Be warned, some
programmers will happily use this stuff, and as the new transputers go
out into the world, many many pieces of software will go "kablowie"
and fall flat on the ground in perfect unison. I hope Inmos doesn't
end up with the blame (perhaps their role as hardware vendor makes
this a different situation).

Me, I'm still irritated that I asked Inmos for the (proper) transputer
instruction set back around 1985 and they said "No; go and program in OCCAM."

	Nick.
--
Nick Rothwell,	Laboratory for Foundations of Computer Science, Edinburgh.
		nick@lfcs.ed.ac.uk    <Atlantic Ocean>!mcsun!ukc!lfcs!nick
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