In TCG, target means the host architecture for which TCG generates
the code. Using guest rather than target to make the document more
consistent.
Signed-off-by: Chen Wei-Ren che...@iis.sinica.edu.tw
---
v3: Adopt Peter's suggestion on sentence and typo.
v2: Correct all wrong usage of the term target in this document.
tcg/README | 14 +-
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/tcg/README b/tcg/README
index 934e7af..063aeb9 100644
--- a/tcg/README
+++ b/tcg/README
@@ -14,6 +14,10 @@ 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 use guest to specify what architecture we are
+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 +383,7 @@ 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 +525,9 @@ 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 +535,9 @@ 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
--
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
