Parrot got rather further along than rattlesnake as a register based VM. I don't think it every really beat CPython in speed though.
On Mon, Mar 11, 2019, 5:57 PM Neil Schemenauer firstname.lastname@example.org wrote:
On 2019-02-27, Victor Stinner wrote:
The compiler begins with using static single assignment form (SSA) but then uses a register allocator to reduce the number of used registers. Usually, at the end you have less than 5 registers for a whole function.
In case anyone is interested on working on this, I dug up some discussion from years ago. Advice from Tim Peters:
[Python-Dev] Rattlesnake progress https://mail.python.org/pipermail/python-dev/2002-February/020172.html https://mail.python.org/pipermail/python-dev/2002-February/020182.html https://mail.python.org/pipermail/python-dev/2002-February/020146.html
Doing a prototype register-based compiler in Python seems like a good idea. Using the 'compiler' package would give you a good start. I think this is the most recent version of that package:
Based on a little poking around, I think it has not been updated for the 16-bit word code. Shouldn't be too hard to make it work though.
I was thinking about the code format on the weekend. Using three-register opcodes seems a good idea. We could could retain the 16-bit word code format. For opcodes that use three registers, use a second word for the last two registers. I.e.
<8 bit opcode><8 bit register #> <8 bit register #><8 bit register #>
Limit the number of registers to 256. If you run out, just push and pop from stack. You want to keep the instruction decode path in the evaluation loop simple and not confuse the CPU branch predictor.
Neil _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/mertz%40gnosis.cx