From: Jacques GARRIGUE <garrigue@kurims.kyoto-u.ac.jp>
To: j.prevost@gmail.com
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Unboxing options, was RE: assertions or exceptions?
Date: Fri, 16 Jul 2004 11:00:17 +0900 (JST) [thread overview]
Message-ID: <20040716.110017.66047488.garrigue@kurims.kyoto-u.ac.jp> (raw)
In-Reply-To: <d849ad2a04071518035946220a@mail.gmail.com>
From: John Prevost <j.prevost@gmail.com>
> Apologies for keeping the conversation going, but since I just thought of this:
>
> Caml's internal pointers are at minimum 4-byte aligned. What about
> using the other "safe" set of trailing bits, "10", to mark options?
> i.e.:
>
> None = ...0010 (2)
> Some None = ...0110 (6)
> Some Some None = ...1010 (10)
> Some Some Some None = ...1110 (14)
>
> and so on? This would remove the need to use a special memory area
> (or check that area) for wrapping and unwrapping. There'd still be a
> cost, but I would think it should be smaller than the cost you
> describe?
>
> That said, I also don't think this is a critical issue.
Now that you tell it, Xavier's idea (and implementation) was actually
along this line.
The trouble is that it doesn't change the cost: you just do an and on
the lower bits rather than on the higher ones.
Might be worth retrying some day, as hardware is changing, but I don't
expect any real change.
Jacques Garrigue
-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
next prev parent reply other threads:[~2004-07-16 2:01 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-15 8:03 [Caml-list] " Radu Grigore
2004-07-15 10:18 ` Richard Jones
2004-07-15 10:28 ` Daniel Andor
2004-07-15 12:49 ` Radu Grigore
2004-07-15 13:33 ` Richard Jones
2004-07-15 13:58 ` Radu Grigore
2004-07-16 18:53 ` Aleksey Nogin
2004-07-17 2:55 ` John Prevost
2004-07-17 14:24 ` David MENTRE
2004-07-15 12:35 ` Jon Harrop
2004-07-15 13:45 ` Radu Grigore
2004-07-15 14:33 ` Jon Harrop
2004-07-15 15:05 ` Radu Grigore
2004-07-15 16:24 ` skaller
2004-07-15 15:38 ` [Caml-list] Unboxing options, was " Brian Hurt
2004-07-15 16:25 ` John Hughes
2004-07-15 17:00 ` Brian Hurt
2004-07-15 17:20 ` John Prevost
2004-07-15 19:14 ` Radu Grigore
2004-07-15 19:56 ` John Carr
2004-07-15 20:48 ` Brian Hurt
2004-07-15 20:49 ` John Carr
2004-07-15 21:15 ` John Prevost
2004-07-15 21:15 ` Karl Zilles
2004-07-15 21:26 ` Brian Hurt
2004-07-15 21:04 ` John Prevost
2004-07-15 21:17 ` skaller
2004-07-15 21:35 ` Brian Hurt
2004-07-15 21:51 ` skaller
2004-07-15 21:42 ` skaller
2004-07-16 0:35 ` Jacques GARRIGUE
2004-07-16 1:03 ` John Prevost
2004-07-16 2:00 ` Jacques GARRIGUE [this message]
2004-07-16 16:40 ` Xavier Leroy
2004-07-19 8:58 ` Damien Doligez
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20040716.110017.66047488.garrigue@kurims.kyoto-u.ac.jp \
--to=garrigue@kurims.kyoto-u.ac.jp \
--cc=caml-list@inria.fr \
--cc=j.prevost@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).