From: Fren Zeee <frenzeee@gmail.com>
To: help-gnu-emacs@gnu.org
Subject: Re: What's the spec for emacs lisp virtual machine ?
Date: Thu, 29 Jul 2010 22:01:33 -0700 (PDT) [thread overview]
Message-ID: <80cc90dc-d66b-4d93-9ff9-dccacec01770@c10g2000yqi.googlegroups.com> (raw)
In-Reply-To: 90d69edf-4e56-4642-ae45-5b987934cf0b@q16g2000prf.googlegroups.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
next prev parent reply other threads:[~2010-07-30 5:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-23 6:12 What's the spec for emacs lisp virtual machine ? Fren Zeee
2010-07-23 8:34 ` Pascal J. Bourguignon
2010-07-23 15:59 ` Fren Zeee
2010-07-23 16:01 ` Fren Zeee
2010-07-23 16:03 ` Fren Zeee
2010-07-23 16:41 ` Pascal J. Bourguignon
2010-07-23 17:57 ` Barry Margolin
2010-07-23 16:40 ` Pascal J. Bourguignon
2010-07-30 3:51 ` mdj
2010-07-30 5:01 ` Fren Zeee [this message]
2010-07-30 5:28 ` mdj
2010-07-30 5:41 ` Fren Zeee
2010-08-02 19:35 ` Barry Margolin
-- strict thread matches above, loose matches on Subject: below --
2010-07-23 6:15 Fren Zeee
2010-07-23 7:28 ` Alfred M. Szmidt
2010-07-23 16:18 ` Fren Zeee
2010-07-23 17:13 ` Chong Yidong
2010-07-23 7:51 ` Thien-Thi Nguyen
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