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Re: [PATCH -tip 3/6 V4.1] x86: instruction decorder API
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: "H. Peter Anvin" <hpa at zytor dot com>
- Cc: Jim Keniston <jkenisto at us dot ibm dot com>, Ingo Molnar <mingo at elte dot hu>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andi Kleen <andi at firstfloor dot org>, kvm at vger dot kernel dot org, Steven Rostedt <rostedt at goodmis dot org>, Frederic Weisbecker <fweisbec at gmail dot com>, Andrew Morton <akpm at linux-foundation dot org>, Arnaldo Carvalho de Melo <acme at redhat dot com>, systemtap-ml <systemtap at sources dot redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, Vegard Nossum <vegard dot nossum at gmail dot com>, Avi Kivity <avi at redhat dot com>, Roland McGrath <roland at redhat dot com>
- Date: Fri, 17 Apr 2009 09:31:46 -0400
- Subject: Re: [PATCH -tip 3/6 V4.1] x86: instruction decorder API
- References: <49D4F4E6.6060401@redhat.com> <49D69BCA.8060506@redhat.com> <49D69F39.4010101@zytor.com> <49D6ABD1.7040704@redhat.com> <1239058135.5212.43.camel@localhost.localdomain> <49DA8857.8030607@zytor.com> <49E7BFDC.8040305@redhat.com> <49E7C1B3.1070000@zytor.com>
H. Peter Anvin wrote:
> Masami Hiramatsu wrote:
>>
>> Hmm, I have an idea about instruction table. Usually, instruction tables
>> are encoded with code defined by each decoder/emulator. This method
>> will show their internal code directly, and is hard to maintain when
>> the opcode map is updated. Instead of that, I'd like to suggest using
>> the expressions in the opcode maps in a vender's genuine document (in
>> this case, Intel/AMD's manual) or www.sandpile.org for instruction
>> tables.
>>
>
> Yes, we discussed this at the Collab Summit. I think it's the only sane
> thing.
>
>> e.g.
>>
>> const insn_attr_t onebyte_attr_table[ATTR_TABLE_SIZE] = {
>> /* 0x00-0x0f */
>> AT2(Eb,Gb), AT2(Ev,Gv), AT2(Gb,Eb), AT2(Gv,Ev),
>> AT2(AL,Ib), AT2(rAX,Iz), AT2(ES,i64), AT2(ES,i64),
>> AT2(Eb,Gb), AT2(Ev,Gv), AT2(Gb,Eb), AT2(Gv,Ev),
>> AT2(AL,Ib), AT2(rAX,Iz), AT2(CS,i64), AT(ESC),
>> ...
>>
>> Here, AT and AT2 macros are defined as follows:
>>
>
> I would suggest using an actual parser, rather than relying on cpp for
> this. The parser will be much more powerful, and will make it much
> easier to change data structure radically as we discussed.
Aah, I see. So we'd better make a parser which generates internal
data structure from genuine opcode map in compilation time.
And I changed my mind about internal data structure too.
In this version, I'll use a smallest bits which are needed
for the decoder.
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com