From: Paolo Bonzini <pbonzini@redhat.com>
To: Andrew Baumann <Andrew.Baumann@microsoft.com>,
Sylvain Garrigues <sylvain@sylvaingarrigues.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
"qemu-arm@nongnu.org" <qemu-arm@nongnu.org>,
Eric Blake <eblake@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-arm] [Qemu-devel] [PATCH] bcm2835_property: use cached values when querying framebuffer
Date: Mon, 9 May 2016 12:27:50 +0200 [thread overview]
Message-ID: <57306626.6050702@redhat.com> (raw)
In-Reply-To: <BLUPR0301MB203485DA67E205999C1F0AC49E6F0@BLUPR0301MB2034.namprd03.prod.outlook.com>
On 22/04/2016 13:30, Andrew Baumann wrote:
>> From: Sylvain Garrigues [mailto:sylvain@sylvaingarrigues.com]
>> Sent: Friday, 22 April 2016 13:27
>>
>> Le 22 avr. 2016 à 13:22, Andrew Baumann
>> <Andrew.Baumann@microsoft.com> a écrit :
>>>> + stl_le_phys(&s->dma_as, value + 16, tmp_xres * tmp_yres
>>>> + * (tmp_bpp >> 3));
>>>
>>> Personal style nit: I prefer * 8 rather than >> 3, because it's more immediately
>> obvious what you're computing, a trivial optimisation for the compiler
Note that it's only trivial for unsigned dividend. A signed dividend
has >> rounding towards -infinity and / rounding towards zero.
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Andrew Baumann <Andrew.Baumann@microsoft.com>,
Sylvain Garrigues <sylvain@sylvaingarrigues.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
Eric Blake <eblake@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
"qemu-arm@nongnu.org" <qemu-arm@nongnu.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] bcm2835_property: use cached values when querying framebuffer
Date: Mon, 9 May 2016 12:27:50 +0200 [thread overview]
Message-ID: <57306626.6050702@redhat.com> (raw)
In-Reply-To: <BLUPR0301MB203485DA67E205999C1F0AC49E6F0@BLUPR0301MB2034.namprd03.prod.outlook.com>
On 22/04/2016 13:30, Andrew Baumann wrote:
>> From: Sylvain Garrigues [mailto:sylvain@sylvaingarrigues.com]
>> Sent: Friday, 22 April 2016 13:27
>>
>> Le 22 avr. 2016 à 13:22, Andrew Baumann
>> <Andrew.Baumann@microsoft.com> a écrit :
>>>> + stl_le_phys(&s->dma_as, value + 16, tmp_xres * tmp_yres
>>>> + * (tmp_bpp >> 3));
>>>
>>> Personal style nit: I prefer * 8 rather than >> 3, because it's more immediately
>> obvious what you're computing, a trivial optimisation for the compiler
Note that it's only trivial for unsigned dividend. A signed dividend
has >> rounding towards -infinity and / rounding towards zero.
Paolo
next prev parent reply other threads:[~2016-05-09 10:27 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-21 10:41 [Qemu-devel] [PATCH] bcm2835_property: use cached values when querying framebuffer Sylvain Garrigues
2016-04-21 10:41 ` Sylvain Garrigues
2016-04-21 12:45 ` [Qemu-arm] " Peter Maydell
2016-04-21 12:45 ` [Qemu-devel] " Peter Maydell
2016-04-21 12:50 ` [Qemu-arm] " Sylvain Garrigues
2016-04-21 12:50 ` [Qemu-devel] " Sylvain Garrigues
2016-04-21 12:54 ` Peter Maydell
2016-04-21 12:54 ` Peter Maydell
2016-04-21 13:15 ` [Qemu-arm] " Sylvain Garrigues
2016-04-21 13:15 ` [Qemu-devel] " Sylvain Garrigues
2016-04-21 13:42 ` [Qemu-arm] " Peter Maydell
2016-04-21 13:42 ` [Qemu-devel] " Peter Maydell
2016-04-21 14:07 ` [Qemu-arm] " Sylvain Garrigues
2016-04-21 14:07 ` [Qemu-devel] " Sylvain Garrigues
2016-04-21 16:06 ` [Qemu-arm] " Stephen Warren
2016-04-21 16:06 ` [Qemu-devel] " Stephen Warren
2016-04-22 7:17 ` Peter Crosthwaite
2016-04-22 7:17 ` [Qemu-devel] " Peter Crosthwaite
2016-04-22 7:46 ` [Qemu-arm] [Qemu-devel] " Gerd Hoffmann
2016-04-22 7:46 ` [Qemu-devel] [Qemu-arm] " Gerd Hoffmann
2016-04-22 11:56 ` Andrew Baumann
2016-04-22 11:56 ` Andrew Baumann
2016-04-22 15:43 ` [Qemu-arm] [Qemu-devel] " Stephen Warren
2016-04-22 15:43 ` [Qemu-devel] [Qemu-arm] " Stephen Warren
2016-04-22 16:50 ` [Qemu-arm] [Qemu-devel] " Peter Crosthwaite
2016-04-22 16:50 ` [Qemu-devel] [Qemu-arm] " Peter Crosthwaite
2016-04-22 11:44 ` Andrew Baumann
2016-04-22 11:44 ` [Qemu-devel] " Andrew Baumann
2016-04-22 16:55 ` Peter Crosthwaite
2016-04-22 16:55 ` [Qemu-devel] " Peter Crosthwaite
2016-04-22 18:09 ` Sylvain Garrigues
2016-04-22 18:09 ` Sylvain Garrigues
2016-04-22 11:22 ` [Qemu-arm] [Qemu-devel] " Andrew Baumann
2016-04-22 11:22 ` Andrew Baumann
2016-04-22 11:26 ` [Qemu-arm] " Sylvain Garrigues
2016-04-22 11:26 ` Sylvain Garrigues
2016-04-22 11:30 ` [Qemu-arm] " Andrew Baumann
2016-04-22 11:30 ` Andrew Baumann
2016-04-22 12:12 ` [Qemu-arm] " Sylvain Garrigues
2016-04-22 12:12 ` Sylvain Garrigues
2016-05-09 10:27 ` Paolo Bonzini [this message]
2016-05-09 10:27 ` Paolo Bonzini
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