From: Richard Henderson <rth@twiddle.net>
To: Max Filippov <jcmvbkbc@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 19/26] target-xtensa: implement loop option
Date: Fri, 20 May 2011 07:14:31 -0700 [thread overview]
Message-ID: <4DD67747.8030604@twiddle.net> (raw)
In-Reply-To: <BANLkTimQSPxhtS4nU9kTRWCWWtiw8wCpwg@mail.gmail.com>
On 05/20/2011 02:10 AM, Max Filippov wrote:
>>> If you're going to pretend that LEND is a constant, you might as well
>>> pretend that LBEG is also a constant, so that you get to chain the TB's
>>> around the loop.
>>
>> But there may be three exits from TB at the LEND if its last
>> command is a branch: to the LBEG, to the branch target and to the
>> next insn.
>
> Ok, I guess that I need to add gen_wsr_lbeg that invalidates TB at the
> current LEND, pretend that LBEG is constant and use given slot to jump
> to it. And also to get rid of tcg_gen_brcondi_i32(TCG_COND_NE,
> cpu_SR[LEND], dc->next_pc, label);
Yes.
Consider that the code is written to assume that the loop cycles,
so the most likely exit at LEND is LBEG. If we choose to mirror
that logic inside TCG, then of the 3 possible exits from the block
one of them should be LBEG so that the most likely edge can get
chained.
r~
next prev parent reply other threads:[~2011-05-20 14:14 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-17 22:32 [Qemu-devel] [PATCH 00/26] target-xtensa: introduce new target architecture Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 01/26] target-xtensa: add target stubs Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 02/26] target-xtensa: add target to the configure script Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 03/26] target-xtensa: implement disas_xtensa_insn Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 04/26] target-xtensa: implement narrow instructions Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 05/26] target-xtensa: implement RT0 group Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 06/26] target-xtensa: add sample board Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 07/26] target-xtensa: implement conditional jumps Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 08/26] target-xtensa: implement JX/RET0/CALLX Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 09/26] target-xtensa: add special and user registers Max Filippov
2011-05-19 20:59 ` Richard Henderson
2011-05-20 7:34 ` Max Filippov
2011-05-20 14:18 ` Richard Henderson
2011-05-17 22:32 ` [Qemu-devel] [PATCH 10/26] target-xtensa: implement RST3 group Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 11/26] target-xtensa: implement shifts (ST1 and RST1 groups) Max Filippov
2011-05-19 21:15 ` Richard Henderson
2011-05-17 22:32 ` [Qemu-devel] [PATCH 12/26] target-xtensa: implement LSAI group Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 13/26] target-xtensa: mark reserved and TBD opcodes Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 14/26] target-xtensa: implement SYNC group Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 15/26] target-xtensa: implement CACHE group Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 16/26] target-xtensa: implement exceptions Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 17/26] target-xtensa: implement RST2 group (32 bit mul/div/rem) Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 18/26] target-xtensa: implement windowed registers Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 19/26] target-xtensa: implement loop option Max Filippov
2011-05-19 21:51 ` Richard Henderson
2011-05-20 7:25 ` Max Filippov
2011-05-20 9:10 ` Max Filippov
2011-05-20 14:14 ` Richard Henderson [this message]
2011-05-17 22:32 ` [Qemu-devel] [PATCH 20/26] target-xtensa: implement extended L32R Max Filippov
2011-05-19 22:00 ` Richard Henderson
2011-05-20 7:14 ` Max Filippov
2011-05-20 15:30 ` Richard Henderson
2011-05-17 22:32 ` [Qemu-devel] [PATCH 21/26] target-xtensa: implement unaligned exception option Max Filippov
2011-05-19 22:04 ` Richard Henderson
2011-05-22 12:10 ` Max Filippov
2011-05-22 16:57 ` Richard Henderson
2011-05-22 20:12 ` Max Filippov
2011-05-23 13:51 ` Richard Henderson
2011-05-23 23:20 ` Max Filippov
2011-05-24 14:57 ` Richard Henderson
2011-05-17 22:32 ` [Qemu-devel] [PATCH 22/26] target-xtensa: implement SIMCALL Max Filippov
2011-05-19 22:07 ` Richard Henderson
2011-05-17 22:32 ` [Qemu-devel] [PATCH 23/26] target-xtensa: implement interrupt option Max Filippov
2011-05-20 15:44 ` Richard Henderson
2011-05-20 20:05 ` Max Filippov
2011-05-20 20:49 ` Richard Henderson
2011-05-20 21:30 ` Max Filippov
2011-05-20 22:19 ` Richard Henderson
2011-05-24 10:28 ` Max Filippov
2011-05-24 14:59 ` Richard Henderson
2011-05-24 15:11 ` Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 24/26] target-xtensa: implement accurate window check Max Filippov
2011-05-20 15:58 ` Richard Henderson
2011-05-20 19:04 ` Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 25/26] target-xtensa: implement CPENABLE and PRID SRs Max Filippov
2011-05-17 22:32 ` [Qemu-devel] [PATCH 26/26] target-xtensa: implement relocatable vectors Max Filippov
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=4DD67747.8030604@twiddle.net \
--to=rth@twiddle.net \
--cc=jcmvbkbc@gmail.com \
--cc=qemu-devel@nongnu.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.