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From: Richard Henderson <rth@twiddle.net>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-devel <qemu-devel@nongnu.org>,
	Aurelien Jarno <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [RFC] Streamlining endian handling in TCG
Date: Wed, 28 Aug 2013 10:16:54 -0700	[thread overview]
Message-ID: <521E3086.1030003@twiddle.net> (raw)
In-Reply-To: <CAFEAcA8j=-gNcSoJmy96HFscjO+zrNop=BUGS1WXRgr7JutpNQ@mail.gmail.com>

On 08/28/2013 09:38 AM, Peter Maydell wrote:
>> (B) Add an additional bit to the "opc" to indicate which endianness is desired.
>>  E.g. 0 = LE, 8 = BE.  Expose the opc interface to the translators.  At which
>> point generating a load becomes more like
>>
>>     tcg_gen_qemu_ld_tl(dest, addr, size | sign | dc->big_endian);
>>
>> and the current endianness of the guest becomes a bit on the TB, to be copied
>> into the DisasContext at the beginning of translation.
> 
> I guess we deal with ARMv5-style BE32 by having the target
> emit an explicit XOR TCG op?

Yes.  I see no other way to implement that.

> Do we need to overhaul the C interface to the
> memory system too? (ie ldl_p and friends).

I don't think so, since we already have ldl_{le,be}_p.


r~

  reply	other threads:[~2013-08-28 17:17 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-28  4:39 [Qemu-devel] [PATCH] target-arm: Report unimplemented opcodes (LOG_UNIMP) Stefan Weil
2013-08-28  8:15 ` Peter Maydell
2013-08-28 14:31   ` Richard Henderson
2013-08-28 14:34     ` Peter Maydell
2013-08-28 15:26       ` [Qemu-devel] [RFC] Streamlining endian handling in TCG Richard Henderson
2013-08-28 16:38         ` Peter Maydell
2013-08-28 17:16           ` Richard Henderson [this message]
2013-08-28 17:28             ` Peter Maydell
2013-08-28 17:45               ` Richard Henderson
2013-08-28 17:41           ` Stefan Weil
2013-08-28 20:42         ` Edgar E. Iglesias
2013-08-28 21:06           ` Peter Maydell
2013-08-28 21:23           ` Richard Henderson
2013-09-02 23:42         ` Aurelien Jarno
2013-09-03 15:11           ` Richard Henderson
2013-09-01 15:35 ` [Qemu-devel] [Qemu-trivial] [PATCH] target-arm: Report unimplemented opcodes (LOG_UNIMP) Michael Tokarev

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