PDP8 / ETOS
rick at rickmurphy.net
Tue Oct 20 20:50:30 CDT 2015
At 06:47 AM 10/20/2015, Noel Chiappa wrote:
> > From: Rick Murphy
> > Lots and lots of fun like that. What an space optimizer would do if
> > there was one. :)
>Wow. You did all that by hand?
Yup. Lots of work. That's kind of why I find the implication that I
don't know what's going on here somewhat disconcerting. :)
>If so, with a program that big, wouldn't it have made sense to try and
>a separate post-processor to do all those optimizations? Surely it
>have been that much work, compared to going through the entire compiler
As with most things, it initially looked to be more work to write
something to parse the code and optimize it. Some of the work was
pretty much rote, but a lot of it took some judgement to find more
compact code. It wasn't until I described the effort that I actually
considered calling it "space optimization". Oh, and some of this was
painfully impacted by the limits of the compiler symbol table sizes,
thus a lot of constants don't get meaningful names.
Ugh. I wouldn't have volunteered for this. I still want to get it to
the point where 28K is possible, but that'll take a new optimization
that I haven't yet thought of. :) Basically, at this point, it's really
a FPP assembler version of Adventure slightly assisted by the Fortran
compiler. I'm pretty proud of the idle loop blinkenlights, though.
Looks good on my PiDP-8.
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