24 Oct
2018
24 Oct
'18
6:19 a.m.
On Oct 23, 2018, at 7:08 PM, Noel Chiappa via cctalk
<cctalk at classiccmp.org> wrote:
...
There was a recent discussion about code density (I forget whether here, or
on TUHS), and someone mentioned this paper:
http://web.eece.maine.edu/~vweaver/papers/iccd09/iccd09_density.pdf
which shows that for a combo of benchmarks, the PDP-11 had the densest code
out of all the ones they looked at. (They didn't look at the PDP-8, but I
suspect that since it's a single-address design, it's almost ceertainly not
as dense.)
The PDP-11 dates back to the days of core (it went through several generations
before DRAM arrived - e.g. the -11/70 originally shipped with core), and given
core prices, minimizing code size was pretty important - hence the results
above.
What's interesting is that the paper uses compiled code. The gcc back end for pdp11
is still a work in progress and clearly doesn't deliver best possible code, certainly
not back then.
paul