Re: [Qemu-trivial] [PATCH v2] Use proper term in TCG README

[Wei-Ren Chen]

  Thanks, Peter. 

On Thu, Mar 14, 2013 at 09:03:15AM +0000, Peter Maydell wrote:
> On 14 March 2013 08:06, 陳韋任 (Wei-Ren Chen) <address@hidden> wrote:
> >   In TCG, "target" means the host architecture for which TCG generates
> > the code. Using "guest" rather than "target" to make the document more
> > consistent.
> 
> Thanks. I've tweaked the wording a little in one sentence below;
> otherwise it looks good.
> 
> > Signed-off-by: Chen Wei-Ren <address@hidden>
> > ---
> >  tcg/README | 13 ++++++++-----
> >  1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/tcg/README b/tcg/README
> > index 934e7af..00d4751 100644
> > --- a/tcg/README
> > +++ b/tcg/README
> > @@ -14,6 +14,9 @@ the emulated architecture. As TCG started as a generic C 
> > backend used
> >  for cross compiling, it is assumed that the TCG target is different
> >  from the host, although it is never the case for QEMU.
> >
> > +In this document, we uses "guest" to specify what architecture we are
> 
> "use".
> 
> 
> > +emulating, and "target" means on what machine we are running QEMU.
> 
> "emulating; "target" always means the TCG target, the machine on which
> we are running QEMU."
> 
> > +
> >  A TCG "function" corresponds to a QEMU Translated Block (TB).
> >
> >  A TCG "temporary" is a variable only live in a basic
> > @@ -379,7 +382,7 @@ double-word product T0.  The later is returned in two 
> > single-word outputs.
> >
> >  Similar to mulu2, except the two inputs T1 and T2 are signed.
> >
> > -********* 64-bit target on 32-bit host support
> > +********* 64-bit guest on 32-bit host support
> >
> >  The following opcodes are internal to TCG.  Thus they are to be 
> > implemented by
> >  32-bit host code generators, but are not to be emitted by guest 
> > translators.
> > @@ -521,9 +524,9 @@ register.
> >    a better generated code, but it reduces the memory usage of TCG and
> >    the speed of the translation.
> >
> > -- Don't hesitate to use helpers for complicated or seldom used target
> > +- Don't hesitate to use helpers for complicated or seldom used guest
> >    instructions. There is little performance advantage in using TCG to
> > -  implement target instructions taking more than about twenty TCG
> > +  implement guest instructions taking more than about twenty TCG
> >    instructions. Note that this rule of thumb is more applicable to
> >    helpers doing complex logic or arithmetic, where the C compiler has
> >    scope to do a good job of optimisation; it is less relevant where
> > @@ -531,9 +534,9 @@ register.
> >    inline TCG may still be faster for longer sequences.
> >
> >  - The hard limit on the number of TCG instructions you can generate
> > -  per target instruction is set by MAX_OP_PER_INSTR in exec-all.h --
> > +  per guest instruction is set by MAX_OP_PER_INSTR in exec-all.h --
> >    you cannot exceed this without risking a buffer overrun.
> >
> >  - Use the 'discard' instruction if you know that TCG won't be able to
> >    prove that a given global is "dead" at a given program point. The
> > -  x86 target uses it to improve the condition codes optimisation.
> > +  x86 guest uses it to improve the condition codes optimisation.
> > --
> > 1.7.12.3
> 
> -- PMM

-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj