From: Nicholas Piggin <npiggin@gmail.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Segher Boessenkool <segher@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/3] powerpc/64: optimise LOAD_REG_IMMEDIATE_SYM()
Date: Tue, 20 Aug 2019 01:05:16 +1000 [thread overview]
Message-ID: <1566226318.3km27rs0o4.astroid@bobo.none> (raw)
In-Reply-To: <20190819142459.GJ31406@gate.crashing.org>
Segher Boessenkool's on August 20, 2019 12:24 am:
> On Mon, Aug 19, 2019 at 01:58:12PM +0000, Christophe Leroy wrote:
>> -#define LOAD_REG_IMMEDIATE_SYM(reg,expr) \
>> - lis reg,(expr)@highest; \
>> - ori reg,reg,(expr)@higher; \
>> - rldicr reg,reg,32,31; \
>> - oris reg,reg,(expr)@__AS_ATHIGH; \
>> - ori reg,reg,(expr)@l;
>> +#define LOAD_REG_IMMEDIATE_SYM(reg, tmp, expr) \
>> + lis reg, (expr)@highest; \
>> + lis tmp, (expr)@__AS_ATHIGH; \
>> + ori reg, reg, (expr)@higher; \
>> + ori tmp, reg, (expr)@l; \
>> + rldimi reg, tmp, 32, 0
>
> That should be
>
> #define LOAD_REG_IMMEDIATE_SYM(reg, tmp, expr) \
> lis tmp, (expr)@highest; \
> ori tmp, tmp, (expr)@higher; \
> lis reg, (expr)@__AS_ATHIGH; \
> ori reg, reg, (expr)@l; \
> rldimi reg, tmp, 32, 0
>
> (tmp is the high half, reg is the low half, as inputs to that rldimi).
I guess the intention was also to try to fit the independent ops into
the earliest fetch/issue cycle possible.
#define LOAD_REG_IMMEDIATE_SYM(reg, tmp, expr) \
lis tmp, (expr)@highest; \
lis reg, (expr)@__AS_ATHIGH; \
ori tmp, tmp, (expr)@higher; \
ori reg, reg, (expr)@l; \
rldimi reg, tmp, 32, 0
Very cool series though.
Thanks,
Nick
next prev parent reply other threads:[~2019-08-19 15:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 13:58 [PATCH v3 1/3] powerpc: rewrite LOAD_REG_IMMEDIATE() as an intelligent macro Christophe Leroy
2019-08-19 13:58 ` [PATCH v3 2/3] powerpc/32: replace LOAD_MSR_KERNEL() by LOAD_REG_IMMEDIATE() Christophe Leroy
2019-08-19 13:58 ` [PATCH v3 3/3] powerpc/64: optimise LOAD_REG_IMMEDIATE_SYM() Christophe Leroy
2019-08-19 14:24 ` Segher Boessenkool
2019-08-19 15:05 ` Nicholas Piggin [this message]
2019-08-19 14:16 ` [PATCH v3 1/3] powerpc: rewrite LOAD_REG_IMMEDIATE() as an intelligent macro Segher Boessenkool
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=1566226318.3km27rs0o4.astroid@bobo.none \
--to=npiggin@gmail.com \
--cc=christophe.leroy@c-s.fr \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=paulus@samba.org \
--cc=segher@kernel.crashing.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).