Re: indirect threading for bytecode interpreter

[Helmut Eller]

* Tom Tromey [2009-09-17 18:46+0200] writes:

> This patch implements indirect threading for the Emacs bytecode
> interpreter.  It uses a GNU C extension, and falls back to the current
> switch-based code if Emacs is compiled with some other compiler.

According to the usual Forth terminology
http://en.wikipedia.org/wiki/Threaded_code
your patch implements token threading not indirect threading.

[Indirect threading uses pointers (to Forth-style "word headers") which
 contain the address of the machine code.  There are no such pointers in
 your patch.  At the machine code level, token threaded code uses a
 "token" as index in a table.  That's what your code is doing.  Unlike
 token threaded code, indirect threaded code is typically not position
 independent.]

Despite that, a few years ago somebody has already proposed that 
http://lists.gnu.org/archive/html/emacs-devel/2004-05/msg00095.html
and it wasn't deemed worthwhile back then.

Helmut