From: Ralf Baechle <ralf@linux-mips.org>
To: Franck Bui-Huu <vagabon.xyz@gmail.com>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>,
ths@networkno.de, linux-mips@linux-mips.org
Subject: Re: [PATCH] setup.c: introduce __pa_symbol() and get ride of CPHYSADDR()
Date: Tue, 10 Oct 2006 22:51:24 +0100 [thread overview]
Message-ID: <20061010215124.GA21012@linux-mips.org> (raw)
In-Reply-To: <452BC4A5.3080706@innova-card.com>
On Tue, Oct 10, 2006 at 06:04:53PM +0200, Franck Bui-Huu wrote:
> ok, and does the trick on KSEG0/XKPHYS really worth ? I mean what is
> the size code gain ?
Gcc / gas generate a 6 instruction sequence to load something from a
64-bit address, basically lui, add, dsll16, add, dsll16, add. It's
just 2 instructions for 32-bit addresses. This boils down to space
savings in the hundred of kilobytes for a kernel.
Of course there are more intelligent way to load an address via global
pointer optimization but that's the two choices we got today.
Ralf
next prev parent reply other threads:[~2006-10-10 21:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-06 13:36 [PATCH] setup.c: introduce __pa_symbol() and get ride of CPHYSADDR() Franck Bui-Huu
2006-10-06 17:21 ` Thiemo Seufer
2006-10-09 11:58 ` Franck Bui-Huu
2006-10-09 13:21 ` Thiemo Seufer
2006-10-09 14:25 ` Franck Bui-Huu
2006-10-09 14:58 ` Thiemo Seufer
2006-10-09 15:30 ` Franck Bui-Huu
2006-10-09 15:51 ` Atsushi Nemoto
2006-10-09 16:59 ` Thiemo Seufer
2006-10-10 8:49 ` Atsushi Nemoto
2006-10-10 13:49 ` Franck Bui-Huu
2006-10-10 14:19 ` Atsushi Nemoto
2006-10-10 15:01 ` Franck Bui-Huu
2006-10-10 15:29 ` Atsushi Nemoto
2006-10-10 16:04 ` Franck Bui-Huu
2006-10-10 16:16 ` Franck Bui-Huu
2006-10-10 21:51 ` Ralf Baechle [this message]
2006-10-11 3:11 ` Atsushi Nemoto
2006-10-11 9:37 ` Franck Bui-Huu
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=20061010215124.GA21012@linux-mips.org \
--to=ralf@linux-mips.org \
--cc=anemo@mba.ocn.ne.jp \
--cc=linux-mips@linux-mips.org \
--cc=ths@networkno.de \
--cc=vagabon.xyz@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