[Python-Dev] A wordcode-based Python

[Cesare Di Mauro]

On Mon, May 11, 2009 10:27PM, Antoine Pitrou wrote:

Hi Antoine

> Hi,
>
>> WPython is a re-implementation of (some parts of) Python, which drops
>> support for bytecode in favour of a wordcode-based model (where a is
>> word
>> is 16 bits wide).
>
> This is great!
> Have you planned to port in to the py3k branch? Or, at least, to trunk?

It was my idea too, but first I need to take a deep look at what parts
of code are changed from 2.6 to 3.0.
That's because I don't know how much work is required for this
"forward" port.

> Some opcode and VM optimizations have gone in after 2.6 was released,
> although
> nothing as invasive as you did.

:-D Interesting.

> About the CISC-y instructions, have you tried merging the fast and const
> arrays
> in frame objects? That way, you need less opcode space (since e.g.
> BINARY_ADD_FAST_FAST will cater with constants as well as local
> variables).
>
> Regards
>
> Antoine.

It's an excellent idea, that needs exploration.

Running my stats tools against all .py files found in Lib and Tools
folders, I discovered that the maximum index used for fast/locals
is 79, and 1853 for constants.

So if I find a way to easily map locals first and constants following
in the same array, your great idea can be implemented saving
A LOT of opcodes and reducing ceval.c source code.

I'll work on that after the two releases that I planned.

Thanks for your precious suggestions!

Cesare