From: Richard Henderson <rth@twiddle.net>
To: Blue Swirl <blauwirbel@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC 20/28] target-xtensa: implement windowed registers
Date: Wed, 04 May 2011 13:07:32 -0700 [thread overview]
Message-ID: <4DC1B204.9040501@twiddle.net> (raw)
In-Reply-To: <BANLkTi=NVrNCXakZ13eJ_hCoz5LjdWaMZQ@mail.gmail.com>
On 05/04/2011 12:35 PM, Blue Swirl wrote:
> On Wed, May 4, 2011 at 3:59 AM, Max Filippov <jcmvbkbc@gmail.com> wrote:
>> See ISA, 4.7.1 for details.
>>
>> Physical registers and currently visible window are separate fields in
>> CPUEnv. Only current window is accessible to TCG. On operations that
>> change window base helpers copy current window to and from physical
>> registers.
>
> I'm not sure how the register windows work, but maybe you could use
> the same trick used for Sparc. There is a pool of registers
> (env->regbase[]), a register window pointer (env->regwptr,
> cpu_regwptr) tracks which are the currently accessible ones. The
> advantage is to avoid copying (not entirely for Sparc due to the
> window overlap).
Sparc loses out on some TCG optimizations because of that, although
to be fair the most effective of these are still in Aurlien's trees.
That said, I still would not recommend a new port to follow suit.
r~
next prev parent reply other threads:[~2011-05-04 20:14 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-04 0:59 [Qemu-devel] [RFC 01/28] target-xtensa: add target stubs Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 02/28] target-xtensa: add target to the configure script Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 03/28] target-xtensa: implement disas_xtensa_insn Max Filippov
2011-05-04 15:39 ` Richard Henderson
2011-05-04 0:59 ` [Qemu-devel] [RFC 04/28] target-xtensa: implement narrow instructions Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 05/28] target-xtensa: implement RT0 group Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 06/28] target-xtensa: add sample board Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 07/28] target-xtensa: add gdb support Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 08/28] target-xtensa: implement conditional jumps Max Filippov
2011-05-04 15:45 ` Richard Henderson
2011-05-04 0:59 ` [Qemu-devel] [RFC 09/28] target-xtensa: implement JX/RET0/CALLX Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 10/28] target-xtensa: add special and user registers Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 11/28] target-xtensa: implement RST3 group Max Filippov
2011-05-04 15:51 ` Richard Henderson
2011-05-04 0:59 ` [Qemu-devel] [RFC 12/28] target-xtensa: implement shifts (ST1 and RST1 groups) Max Filippov
2011-05-04 16:16 ` Richard Henderson
2011-05-04 16:39 ` Max Filippov
2011-05-04 19:07 ` Richard Henderson
2011-05-05 8:40 ` Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 13/28] target-xtensa: implement LSAI group Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 14/28] target-xtensa: mark reserved and TBD opcodes Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 15/28] target-xtensa: big endian support Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 16/28] target-xtensa: implement SYNC group Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 17/28] target-xtensa: implement CACHE group Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 18/28] target-xtensa: implement exceptions Max Filippov
2011-05-04 16:33 ` Richard Henderson
2011-05-04 17:00 ` Richard Henderson
2011-05-09 19:38 ` Max Filippov
2011-05-09 20:32 ` Richard Henderson
2011-05-04 0:59 ` [Qemu-devel] [RFC 19/28] target-xtensa: implement RST2 group (32 bit mul/div/rem) Max Filippov
2011-05-04 19:36 ` Blue Swirl
2011-05-05 8:27 ` Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 20/28] target-xtensa: implement windowed registers Max Filippov
2011-05-04 19:35 ` Blue Swirl
2011-05-04 20:07 ` Richard Henderson [this message]
2011-05-04 20:13 ` Blue Swirl
2011-05-04 20:30 ` Richard Henderson
2011-05-04 0:59 ` [Qemu-devel] [RFC 21/28] target-xtensa: implement loop option Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 22/28] target-xtensa: implement extended L32R Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 23/28] target-xtensa: implement unaligned exception option Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 24/28] target-xtensa: implement SIMCALL Max Filippov
2011-05-04 19:48 ` Blue Swirl
2011-05-04 20:31 ` Peter Maydell
2011-05-04 0:59 ` [Qemu-devel] [RFC 25/28] target-xtensa: implement interrupt option Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 26/28] target-xtensa: implement accurate window check Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 27/28] target-xtensa: implement CPENABLE and PRID SRs Max Filippov
2011-05-04 0:59 ` [Qemu-devel] [RFC 28/28] target-xtensa: implement relocatable vectors Max Filippov
2011-05-04 6:04 ` [Qemu-devel] [RFC 01/28] target-xtensa: add target stubs Max Filippov
2011-05-04 19:51 ` Blue Swirl
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