Message-ID: <534FF43A.109@oracle.com>
Date: Thu, 17 Apr 2014 11:33:14 -0400
From: Sasha Levin <sasha.levin@oracle.com>
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To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
CC: vegard.nossum@oracle.com, penberg@kernel.org, jamie.iles@oracle.com,
        hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de, x86@kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@vger.kernel.org
Subject: Re: [PATCH 3/4] x86/insn: Extract more information about instructions
References: <1397497450-6440-1-git-send-email-sasha.levin@oracle.com> <1397497450-6440-3-git-send-email-sasha.levin@oracle.com> <534CA38C.80501@hitachi.com> <534D4BF3.3020102@oracle.com> <534E18B1.4020802@hitachi.com>
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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 :)

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...).


Thanks,
Sasha
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