Re: What's the spec for emacs lisp virtual machine ?

[Fren Zeee <frenzeee@gmail.com>]

On Jul 29, 8:51 pm, mdj <mdj....@gmail.com> wrote:
> On Jul 23, 4:12 pm, Fren Zeee <frenz...@gmail.com> wrote:
>
> > Why is a VM needed when there is compiled C code running machine
> > code ?
>
> The are two essential reasons. Firstly, the bytecode is more compact
> in memory than either the machine code or the READ lisp code.
> Secondly, it loads a good deal faster from disk, allowing emacs to
> start (relatively) quickly.

an example

preferably from an emacs file from savannah link so one could get an
idea of the animal.

theoretical reasons for speed ?

> Thirdly, it is relatively straightforward to implement a portable
> bytecode interpreter in C that will then compile on any architecture
> for which one has a C compiler. This is a great deal less work than
> developing a 'to-machine-code' compiler for every architecture out
> there.

Why is it less than porting the C compiler ? How would it be written ?
assembler ?

> Keep in mind that the early releases of GNU Emacs were in the mid
> 1980's when personal computers powerful enough to run Emacs had
> typically perhaps 1mb of RAM. Keeping the in-memory footprint of Emacs
> small was more important than raw speed which would need more RAM, and
> necessitate customizer the code generator for every conceivable
> architecture.


> In 1989 there were a LOT of 32bit microprocessor architectures out
> there, and many still survive to this day.

> To answer the rest of your questions, I'd recommend enrolling in a
> good computer science degree.

I am sure someone can point to a tutorial paper or book,

no one need you to give that obvious advice ... so obvious that i
consider rude

> Matt