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Date: Mon, 16 Feb 2015 19:11:47 -0500
From: Chris Metcalf <cmetcalf@ezchip.com>
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Subject: Re: [Qemu-devel] [PATCH 1/5] target-tile: Firstly add to qemu with
 minimized features
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To: Peter Maydell <peter.maydell@linaro.org>, Chen Gang S <gang.chen@sunrus.com.cn>
Cc: Max Filippov <jcmvbkbc@gmail.com>, "rth@twiddle.net" <rth@twiddle.net>, Riku Voipio <riku.voipio@iki.fi>, qemu-devel <qemu-devel@nongnu.org>, "walt@tilera.com" <walt@tilera.com>

On 2/16/2015 6:46 PM, Peter Maydell wrote:
> On 17 February 2015 at 08:08, Chen Gang S <gang.chen@sunrus.com.cn> wrote:
>> On 2/16/15 23:24, Max Filippov wrote:
>>> Disassembler is not a crucial part of QEMU target.
>> For me, it is necessary. We need disassemble target binary instructions
>> (recognize them), then translate them into tcg instructions which are
>> grouped by Translate Block.
> No, Max is correct. What QEMU calls the "disassembler" is just
> used for debug logging: it is code that goes from target binary
> instructions to printed display of assembly language instructions.
> This is completely separate code from the code in target-*/translate.c
> which decodes target binary instructions and emits TCG opcodes.
> That code is generally called the translator or the decoder, and
> it is always written from scratch specifically for QEMU. Don't
> try to reuse code from binutils there.

The kernel disassembly that Chen Gang is looking at is basically just an
instruction recognizer; it doesn't even include text strings for opcodes,
for example.  But my guess is that it is exactly the right starting building
block for decoding target binary instructions.

-- 
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com