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From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
In-reply-to: <e10ebfad-354c-a476-7114-17f500551369@twiddle.net>
Date: Thu, 23 Jun 2016 20:58:06 +0100
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Subject: Re: [Qemu-devel] [RFC v3 PATCH 03/14] tcg/aarch64: Add support for
 fence
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To: Richard Henderson <rth@twiddle.net>
Cc: Pranith Kumar <bobby.prani@gmail.com>, Claudio Fontana <claudio.fontana@huawei.com>, "open list:AArch64 target" <qemu-arm@nongnu.org>, "open list:All patches CC here" <qemu-devel@nongnu.org>, serge.fdrv@gmail.com, Claudio Fontana <claudio.fontana@gmail.com>


Richard Henderson <rth@twiddle.net> writes:

> On 06/23/2016 09:18 AM, Alex Bennée wrote:
>>> > +    /* System instructions.  */
>>> > +    DMB_ISH         = 0xd50338bf,
>> As ISH is part of the CRm encoding I wonder if this should be split into
>> the main DMB encoding (0xd50330bf) and a separate set of CRm defines.
>>
>> In fact the documentation of the struct above implies you should
>> probably have:
>>
>>        I6260_DMB       = 0xd50330bf,
>>
>> And then:
>>
>> static void tcg_out_insn_6260(TCGContext *s, AArch64Insn insn, int crm);
>> {
>>     tcg_out32(s, insn | (crm & 0xf) << 8);
>> }
>
> I don't see any benefit to doing this over or-ing in the pre-shifted
> values.

I'm mainly thinking about keeping in line with the layout of the rest of
the code. I would home the compiler would generate the same either way!

--
Alex Bennée