On 14 March 2013 08:06, 陳韋任 (Wei-Ren Chen) <che...@iis.sinica.edu.tw> 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 <che...@iis.sinica.edu.tw> > --- > 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
