On Sep 19, 2007, at 4:39 PM, Jocelyn Mayer wrote:
On Wed, 2007-09-19 at 12:56 +0200, Alexander Graf wrote:
On Sep 19, 2007, at 1:28 AM, Paul Brook wrote:
Ok, I will try to shift the intercepts in an uint_64 flags
variable
in the TB.
OK, great. Having 64 bits may also help for additional (ie
future...)
features in PowerPC 64 emulation.
Maybe worth letting the target say whether it needs 32 or 64-bit
flags.
The flag lookup is likely to be on a hot path.
Paul
here comes the patch.
The patch looks correct to me, I'm just wondering why a cast to 32
bits
is needed in mips code ?
It's not needed - I just did it so one can see that there is
potential that is not used right now and someone should think about
it. I'm not too much into mips so I have no clues if they have any
use for more that 32 bits of flags.
I may be wrong, but it seems to me that TB flags are only used to be
compared in tb_find_fast and tb_find_slow, which are not a very fast
path (we come here when we cannot jump directly to the next tb and are
not in the most time critical code) then we can afford adding a few
asm
instructions (I would say max 2 ?) to replace a 32 bits comparison
with
a 64 bits one. My feeling is that the performance loss here won't be
sensible, but that may need to be proved.
I actually don't even believe the difference can be measured at all,
which is why I seperated the patches.
Cheers,
Alex
