linux-kernel - Re: [PATCH 3/4] x86/insn: Extract more information about instructions

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Message-ID: <53509B30.8070008@hitachi.com>
Date:	Fri, 18 Apr 2014 12:25:36 +0900
From:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To:	Sasha Levin <sasha.levin@...cle.com>
Cc:	vegard.nossum@...cle.com, penberg@...nel.org,
	jamie.iles@...cle.com, hpa@...or.com, mingo@...hat.com,
	tglx@...utronix.de, x86@...nel.org, linux-kernel@...r.kernel.org,
	linux-mm@...r.kernel.org
Subject: Re: [PATCH 3/4] x86/insn: Extract more information about instructions

(2014/04/18 0:33), Sasha Levin wrote:
> On 04/16/2014 01:44 AM, Masami Hiramatsu wrote:
>> Same thing can be done in awk part and insn.c, and we can encode it by
>>
>> #define INAT_MAKE_MEMSZ(size) (size << INAT_MEMSZ_OFFS)
>>
>> And decode it by
>>
>> insn->memsz_bytes = 1 << ((attr & INAT_MEMSZ_MASK) >> INAT_MEMSZ_OFFS)
>>
>> Thus, we only need 3 bits to represent 1, 2, 4, 8, 16 and 32. :)
> 
> We'll need 4 so that we could do 64 too :)

Would you mean AVX512? Actually it's not supported currently :(
anyway, that's ok for me, and also, we need another 2 bits for
the operands which depends on address-size prefix and operand-size prefix.

> btw, why aren't we using regular bitfields? this manual encoding
> thingie seems to be a bit confusing (try figuring out how many
> bits are left...).

Ah, right. OK, I'll try to do that :)

Thank you!

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com


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