On 17 Aug 2006 14:01:51 +0700, Egor Pasko <[EMAIL PROTECTED]> wrote:
On the 0x1C8 day of Apache Harmony Weldon Washburn wrote:
> Windows uses ia32 segment register fs:14 for fast thread-local storage
> access. I think Linux somehow uses the gs segment register.
In general, it is implementation-specific (not older kernels).
Here is a good link for that:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4915203
I took a look. It mentions some kernels use GS register, some have an
TLS related API that uses the LDT and some use the upper 10 bits of
ESP as a unique thread value. The upper 10 can then be used as an
index or hash into a JVM data struct that holds thread local data.
We need some approach to handle old linux kernels that use ESP. Maybe
add a compiler instrinsic that returns the current ESP contents
shifted right by 22 bits. Something like:
int index = espShiftedRightBy22Bits();
I wonder, how to handle system-dependent code with Java vmmagic :(
A simple if-then-else would make an #ifdef replacement?
Good point. We should have a project-wide standard on "java #ifdef".
Feel free to propose something.
--
Egor Pasko, Intel Managed Runtime Division
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--
Weldon Washburn
Intel Middleware Products Division
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