From: a.ryabinin@samsung.com (Andrey Ryabinin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: memset: zero out upper bytes in r1
Date: Thu, 08 May 2014 11:59:02 +0400 [thread overview]
Message-ID: <536B3946.9070106@samsung.com> (raw)
In-Reply-To: <20140507234255.GA2050@afzal-ThinkPad-R50e>
On 05/08/14 03:42, Afzal Mohammed wrote:
>
> int is to be converted to unsigned char in memset, would having above
> change immediately upon entry to memset rather than at a place where it
> won't always execute make intention clearer ? (although it doesn't make
> difference)
>
I think it's better to keep it near other manipulations with r1.
Plus this will save us from executing extra instruction on 'memset -> 6 -> 5 -> return'
path (memset for size <= 3).
> ubfx r1, r1, #0, #8 would have given the needed typecasting, but seems
> it is available only on ARMv6T2 & above.
>
Indeed. It might be wrapped it with #if #else, but it will be a bit ugly,
probably not worth to do.
WARNING: multiple messages have this Message-ID (diff)
From: Andrey Ryabinin <a.ryabinin@samsung.com>
To: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Cc: linux@arm.linux.org.uk, open list <linux-kernel@vger.kernel.org>,
"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm: memset: zero out upper bytes in r1
Date: Thu, 08 May 2014 11:59:02 +0400 [thread overview]
Message-ID: <536B3946.9070106@samsung.com> (raw)
In-Reply-To: <20140507234255.GA2050@afzal-ThinkPad-R50e>
On 05/08/14 03:42, Afzal Mohammed wrote:
>
> int is to be converted to unsigned char in memset, would having above
> change immediately upon entry to memset rather than at a place where it
> won't always execute make intention clearer ? (although it doesn't make
> difference)
>
I think it's better to keep it near other manipulations with r1.
Plus this will save us from executing extra instruction on 'memset -> 6 -> 5 -> return'
path (memset for size <= 3).
> ubfx r1, r1, #0, #8 would have given the needed typecasting, but seems
> it is available only on ARMv6T2 & above.
>
Indeed. It might be wrapped it with #if #else, but it will be a bit ugly,
probably not worth to do.
next prev parent reply other threads:[~2014-05-08 7:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-05 7:11 [PATCH] arm: memset: zero out upper bytes in r1 Andrey Ryabinin
2014-05-05 7:11 ` Andrey Ryabinin
2014-05-07 23:42 ` Afzal Mohammed
2014-05-07 23:42 ` Afzal Mohammed
2014-05-08 7:59 ` Andrey Ryabinin [this message]
2014-05-08 7:59 ` Andrey Ryabinin
2014-05-08 14:40 ` Andrey Ryabinin
2014-05-08 14:40 ` Andrey Ryabinin
2014-05-08 8:04 ` Vladimir Murzin
2014-05-08 8:38 ` Vladimir Murzin
2014-05-12 6:58 ` Andrey Ryabinin
2014-05-12 6:58 ` Andrey Ryabinin
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