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

[Fren Zeee]

On Jul 29, 10:28 pm, mdj <mdj....@gmail.com> wrote:
> On Jul 30, 3:01 pm, Fren Zeee <frenz...@gmail.com> wrote:
>
>
>
>
>
> > 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.
>
> Any emacs lisp source file will serve as an example.
>
> > theoretical reasons for speed ?
>
> bytecode is simpler to parse, and more compact in its representation
> than s-expressions represented as cons cells.
>
> > > 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 ?
>
> Are you suggesting the emacs lisp compiler could target C instead of
> bytecode?
>
> > > 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


> Okay, but your relatively poor command of english is making you appear
> very rude as well. Perhaps consider using more words to describe what
> you mean. The odd gratuity like 'please' and 'thanks' would do wonders
> for your style.- Hide quoted text -

If you had given a concrete example, it would have come out
automatically.

There are two pre-requisites for giving such a useful clear reply. One
is
technical competence, and another is generosity.

Its obvious that you lack one or the other so I wont get into an
argument with you.