From: Segher Boessenkool <segher@kernel.crashing.org>
To: Joel Stanley <joel@jms.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
linux-fbdev@vger.kernel.org, kvm@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dri-devel@lists.freedesktop.org,
Paul Mackerras <paulus@samba.org>,
alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/5] powerpc: Replace _ALIGN_DOWN() by ALIGN_DOWN()
Date: Tue, 21 Apr 2020 10:55:16 -0500 [thread overview]
Message-ID: <20200421155516.GT26902@gate.crashing.org> (raw)
In-Reply-To: <CACPK8XfqnqgkXcBzp=nqd=AJX1MK05eTNiyOdaEuRu3_6RsXSQ@mail.gmail.com>
Hi!
On Tue, Apr 21, 2020 at 01:04:05AM +0000, Joel Stanley wrote:
> On Mon, 20 Apr 2020 at 18:38, Christophe Leroy <christophe.leroy@c-s.fr> wrote:
> > _ALIGN_DOWN() is specific to powerpc
> > ALIGN_DOWN() is generic and does the same
> >
> > Replace _ALIGN_DOWN() by ALIGN_DOWN()
>
> This one is a bit less obvious. It becomes (leaving the typeof's alone
> for clarity):
>
> -((addr)&(~((typeof(addr))(size)-1)))
> +((((addr) - ((size) - 1)) + ((typeof(addr))(size) - 1)) &
> ~((typeof(addr))(size)-1))
>
> Which I assume the compiler will sort out?
[ This is line-wrapped, something in your mailer? Took me a bit to figure
out the - and + are diff -u things :-) ]
In the common case where size is a constant integer power of two, the
compiler will have no problem with this. But why do so complicated?
Why are the casts there, btw?
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Joel Stanley <joel@jms.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
linux-fbdev@vger.kernel.org, kvm@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dri-devel@lists.freedesktop.org,
Paul Mackerras <paulus@samba.org>,
alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/5] powerpc: Replace _ALIGN_DOWN() by ALIGN_DOWN()
Date: Tue, 21 Apr 2020 15:55:16 +0000 [thread overview]
Message-ID: <20200421155516.GT26902@gate.crashing.org> (raw)
In-Reply-To: <CACPK8XfqnqgkXcBzp=nqd=AJX1MK05eTNiyOdaEuRu3_6RsXSQ@mail.gmail.com>
Hi!
On Tue, Apr 21, 2020 at 01:04:05AM +0000, Joel Stanley wrote:
> On Mon, 20 Apr 2020 at 18:38, Christophe Leroy <christophe.leroy@c-s.fr> wrote:
> > _ALIGN_DOWN() is specific to powerpc
> > ALIGN_DOWN() is generic and does the same
> >
> > Replace _ALIGN_DOWN() by ALIGN_DOWN()
>
> This one is a bit less obvious. It becomes (leaving the typeof's alone
> for clarity):
>
> -((addr)&(~((typeof(addr))(size)-1)))
> +((((addr) - ((size) - 1)) + ((typeof(addr))(size) - 1)) &
> ~((typeof(addr))(size)-1))
>
> Which I assume the compiler will sort out?
[ This is line-wrapped, something in your mailer? Took me a bit to figure
out the - and + are diff -u things :-) ]
In the common case where size is a constant integer power of two, the
compiler will have no problem with this. But why do so complicated?
Why are the casts there, btw?
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Joel Stanley <joel@jms.id.au>
Cc: linux-fbdev@vger.kernel.org, kvm@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dri-devel@lists.freedesktop.org,
Paul Mackerras <paulus@samba.org>,
alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/5] powerpc: Replace _ALIGN_DOWN() by ALIGN_DOWN()
Date: Tue, 21 Apr 2020 10:55:16 -0500 [thread overview]
Message-ID: <20200421155516.GT26902@gate.crashing.org> (raw)
In-Reply-To: <CACPK8XfqnqgkXcBzp=nqd=AJX1MK05eTNiyOdaEuRu3_6RsXSQ@mail.gmail.com>
Hi!
On Tue, Apr 21, 2020 at 01:04:05AM +0000, Joel Stanley wrote:
> On Mon, 20 Apr 2020 at 18:38, Christophe Leroy <christophe.leroy@c-s.fr> wrote:
> > _ALIGN_DOWN() is specific to powerpc
> > ALIGN_DOWN() is generic and does the same
> >
> > Replace _ALIGN_DOWN() by ALIGN_DOWN()
>
> This one is a bit less obvious. It becomes (leaving the typeof's alone
> for clarity):
>
> -((addr)&(~((typeof(addr))(size)-1)))
> +((((addr) - ((size) - 1)) + ((typeof(addr))(size) - 1)) &
> ~((typeof(addr))(size)-1))
>
> Which I assume the compiler will sort out?
[ This is line-wrapped, something in your mailer? Took me a bit to figure
out the - and + are diff -u things :-) ]
In the common case where size is a constant integer power of two, the
compiler will have no problem with this. But why do so complicated?
Why are the casts there, btw?
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Joel Stanley <joel@jms.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
linux-fbdev@vger.kernel.org, kvm@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dri-devel@lists.freedesktop.org,
Paul Mackerras <paulus@samba.org>,
alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/5] powerpc: Replace _ALIGN_DOWN() by ALIGN_DOWN()
Date: Tue, 21 Apr 2020 10:55:16 -0500 [thread overview]
Message-ID: <20200421155516.GT26902@gate.crashing.org> (raw)
In-Reply-To: <CACPK8XfqnqgkXcBzp=nqd=AJX1MK05eTNiyOdaEuRu3_6RsXSQ@mail.gmail.com>
Hi!
On Tue, Apr 21, 2020 at 01:04:05AM +0000, Joel Stanley wrote:
> On Mon, 20 Apr 2020 at 18:38, Christophe Leroy <christophe.leroy@c-s.fr> wrote:
> > _ALIGN_DOWN() is specific to powerpc
> > ALIGN_DOWN() is generic and does the same
> >
> > Replace _ALIGN_DOWN() by ALIGN_DOWN()
>
> This one is a bit less obvious. It becomes (leaving the typeof's alone
> for clarity):
>
> -((addr)&(~((typeof(addr))(size)-1)))
> +((((addr) - ((size) - 1)) + ((typeof(addr))(size) - 1)) &
> ~((typeof(addr))(size)-1))
>
> Which I assume the compiler will sort out?
[ This is line-wrapped, something in your mailer? Took me a bit to figure
out the - and + are diff -u things :-) ]
In the common case where size is a constant integer power of two, the
compiler will have no problem with this. But why do so complicated?
Why are the casts there, btw?
Segher
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-04-21 15:56 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-20 18:36 [PATCH 1/5] drivers/powerpc: Replace _ALIGN_UP() by ALIGN() Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` [PATCH 2/5] powerpc: Replace _ALIGN_DOWN() by ALIGN_DOWN() Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 15:55 ` Segher Boessenkool [this message]
2020-04-21 15:55 ` Segher Boessenkool
2020-04-21 15:55 ` Segher Boessenkool
2020-04-21 15:55 ` Segher Boessenkool
2020-04-20 18:36 ` [PATCH 3/5] powerpc: Replace _ALIGN_UP() by ALIGN() Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-20 18:36 ` [PATCH 4/5] powerpc: Replace _ALIGN() " Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-21 1:11 ` Joel Stanley
2020-04-21 1:11 ` Joel Stanley
2020-04-21 1:11 ` Joel Stanley
2020-04-21 1:11 ` Joel Stanley
2020-04-20 18:36 ` [PATCH 5/5] powerpc: Remove _ALIGN_UP(), _ALIGN_DOWN() and _ALIGN() Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-20 18:36 ` Christophe Leroy
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 1:04 ` Joel Stanley
2020-04-21 0:49 ` [PATCH 1/5] drivers/powerpc: Replace _ALIGN_UP() by ALIGN() Joel Stanley
2020-04-21 0:49 ` Joel Stanley
2020-04-21 0:49 ` Joel Stanley
2020-04-21 0:49 ` Joel Stanley
2020-05-20 10:59 ` Michael Ellerman
2020-05-20 10:59 ` Michael Ellerman
2020-05-20 10:59 ` Michael Ellerman
2020-05-20 10:59 ` Michael Ellerman
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=20200421155516.GT26902@gate.crashing.org \
--to=segher@kernel.crashing.org \
--cc=alsa-devel@alsa-project.org \
--cc=christophe.leroy@c-s.fr \
--cc=dri-devel@lists.freedesktop.org \
--cc=joel@jms.id.au \
--cc=kvm@vger.kernel.org \
--cc=linux-fbdev@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=paulus@samba.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.