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
next prev parent 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
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