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From "Estelle Liu" <lyy1...@gmail.com>
Subject Re: [jitrino]HIR instructions
Date Fri, 02 Mar 2007 01:57:29 GMT
Thanks,
and does there anything I can do to dump the HIR instructions of a method
body?


01 Mar 2007 14:46:24 +0300, Egor Pasko <egor.pasko@gmail.com>:
>
> On the 0x28C day of Apache Harmony Estelle Liu wrote:
> > hi,
> > there are some tau instructions of HIR such as Op_TauDiv and
> Op_TauLdInd,
> > what do they stand for?
> > How can I get descriptions about HIR instructions?
>
> Estelle,
>
> there is no complete reference guide for HIR instructions yet. How do
> we tell what operations' semantics are?  The
> jitrino/src/optimizer/Opcode.cpp file helps. For example:
>
> description:
>    { Op_TauDiv,                false, MB::Movable,
> MK::Signed_and_Strict,                     "div   ",        "div%m   %0,%1
> ((%2)) -) %l",             }, // (opnds must already be checked for
> 0/overflow)
>
> "div" says it is division. On printing it tells about 3 source
> operands (%0, %1, %2) and one destination operand (%l). Operand ((%2))
> is a "tau-operand" (because in double-brachets) that comes from
> instruction performing a zero-check (with this tau-operand we ensure
> that zero-check is performed before the actual division).
>
> description2:
>    { Op_TauLdInd,              false,
> MB::Load,          MK::AutoCompress_Speculative,              "ldind",
> "ldind%m:%t [%0] ((%1,%2)) -) %l",          },
>
> This is an indirect load from memory :)
> Checked with two tau operands (null-check and bounds-check, AFAIR)
>
> --
> Egor Pasko
>
>


-- 
Estelle

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