[virtmach] parrot VM?
Sun, 14 Jul 2002 05:50:41 -0500
Anton Ertl wrote (Sun, Jul 14, 2002 at 09:01:39AM +0200) :
> Norman Ramsey wrote:
> > The Lua implementors (www.lua.org) claim to have got a performance
> > improvement by switching from a stack vm to a register vm (with
> > effectively infinitely many registers).
> If you remember where you read about the Lua register VM, I would
> appreciate a reference. Thanks in advance,
From the lua mailing list archives:
I browsed through the lua-4.0.1 sources. It
does seem to be a register VM now. The
instruction format allows specifying two
integers in addition to the opcodes, and
these are used to access local vars by indexing
into the single execution stack, thus
allowing effectively infinite regs as
Norman pointed out. The HISTORY file
mentions a 20% speedup due to the VM change
and this might be because earlier
local var access required extra instructions
(as pointed out in one of the above messages).