[Python-Dev] Python 3 optimizations continued...

[stefan brunthaler]

> Do you really need it to match a machine word? Or is, say, a 16-bit
> format sufficient.
>
Hm, technically no, but practically it makes more sense, as (at least
for x86 architectures) having opargs and opcodes in half-words can be
efficiently expressed in assembly. On 64bit architectures, I could
also inline data object references that fit into the 32bit upper half.
It turns out that most constant objects fit nicely into this, and I
have used this for a special cache region (again below 2^32) for
global objects, too. So, technically it's not necessary, but
practically it makes a lot of sense. (Most of these things work on
32bit systems, too. For architectures with a smaller size, we can
adapt or disable the optimizations.)

Cheers,
--stefan