All of lore.kernel.org
 help / color / mirror / Atom feed
From: Chris Friesen <cfriesen@nortel.com>
To: Kumar Gala <kumar.gala@freescale.com>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: question on inline assembly and long long values
Date: Wed, 06 Apr 2005 14:01:20 -0600	[thread overview]
Message-ID: <42544010.4020105@nortel.com> (raw)
In-Reply-To: <2b5cd7aefbd800842537d00be729d169@freescale.com>

Kumar Gala wrote:
> I'm having a similar need (for a different purpose), this post might be 
> useful:
> 
> http://gcc.gnu.org/ml/gcc/2005-04/msg00283.html

Sweet!  My new code is now shorter *and* more efficient:

static inline unsigned long long getmsr()
{
	unsigned long long val;
         asm volatile( \
                 "mfmsr  %L0               \n\t" \
                 "rldicl %0,%L0,32,32       \n\t" \
                 "rldicl %L0,%L0,0,32        \n\t" \
                 : "=r" (val));
	return val;
}

This results in

unsigned long long a = asdf3();
unsigned long long b = asdf3();

being compiled to

	mfmsr  6
	rldicl 5,6,32,32
	rldicl 6,6,0,32
	
	mfmsr  8
	rldicl 7,8,32,32
	rldicl 8,8,0,32

Which is about as good as it gets...

Thanks!

Chris

  reply	other threads:[~2005-04-06 20:01 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-06 18:26 question on inline assembly and long long values Chris Friesen
2005-04-06 19:16 ` Kumar Gala
2005-04-06 20:01   ` Chris Friesen [this message]
2005-04-06 21:18     ` Gabriel Paubert
2005-04-06 21:37       ` Chris Friesen
2005-04-06 23:19 ` Benjamin Herrenschmidt
2005-04-06 23:30   ` Chris Friesen
2005-04-06 23:49     ` Benjamin Herrenschmidt
2005-04-06 23:56       ` Chris Friesen
2005-04-06 23:57         ` Benjamin Herrenschmidt
2005-04-07  0:09           ` Chris Friesen

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=42544010.4020105@nortel.com \
    --to=cfriesen@nortel.com \
    --cc=kumar.gala@freescale.com \
    --cc=linuxppc-dev@ozlabs.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.