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From: Sam Ravnborg <sam@ravnborg.org>
To: sparclinux@vger.kernel.org
Subject: Re: [PATCH] sparc: cleaned up FPU version probing
Date: Thu, 27 Jan 2011 17:34:56 +0000	[thread overview]
Message-ID: <20110127173456.GA4487@merkur.ravnborg.org> (raw)
In-Reply-To: <1296126392-7536-1-git-send-email-daniel@gaisler.com>

On Thu, Jan 27, 2011 at 11:14:16AM +0000, Richard Mortimer wrote:
>
>
> On 27/01/2011 11:06, Daniel Hellstrom wrote:
>> Signed-off-by: Daniel Hellstrom<daniel@gaisler.com>
>> ---
>>   arch/sparc/include/asm/psr.h |   51 ++++++++++++++++++++++++++++++++++++++++++
>>   arch/sparc/kernel/cpu.c      |   11 +++++---
>>   2 files changed, 58 insertions(+), 4 deletions(-)
>>
> ...
>
>> diff --git a/arch/sparc/kernel/cpu.c b/arch/sparc/kernel/cpu.c
>> index 7925c54..bc8d5ef 100644
>> --- a/arch/sparc/kernel/cpu.c
>> +++ b/arch/sparc/kernel/cpu.c
>> @@ -318,15 +318,18 @@ void __cpuinit cpu_probe(void)
>>   	int psr_impl, psr_vers, fpu_vers;
>>   	int psr;
>>
>> -	psr_impl = ((get_psr()>>  28)&  0xf);
>> -	psr_vers = ((get_psr()>>  24)&  0xf);
>> +	psr_impl = ((get_psr()&  PSR_IMPL)>>  PSR_IMPL_SHIFT);
> This is going to break. If the top bit of psr_impl is set it
> will get sign extended when the left shift is done.

That would not matter as we use the " & PSR_IMPL" to clear
the unused upper bits.
So IMO the patch is correct.

	Sam

  parent reply	other threads:[~2011-01-27 17:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-27 11:06 [PATCH] sparc: cleaned up FPU version probing Daniel Hellstrom
2011-01-27 11:14 ` Richard Mortimer
2011-01-27 11:21 ` Richard Mortimer
2011-01-27 17:34 ` Sam Ravnborg [this message]
2011-01-27 17:36 ` Sam Ravnborg
2011-01-27 18:39 ` Richard Mortimer
2011-01-27 19:36 ` Sam Ravnborg
2011-01-28 23:09 ` David Miller
2011-01-31 17:00 ` Daniel Hellstrom

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