The NX bit is an issue in the Java VM, exactly because it creates native code at run time by allocating memory and writing to it, before executing it. Normally, executable code is now writable, and writable memory should not be executable. So the memory block must be allocated differently, and the Java VM for AMD64 must be modified to support the new memory allocation mode.
Also You have missed important words in my sentence before sayin "non sense": I said "until then" to refer to other architectures than 32-bit ones. When running in 32-bit mode, no pointer is larger than 32-bit, so the VM is limited to 4GB. A larger VM requires a new port to support 64-bit running mode.
[/QUOTE]
Quote:
|
Where have you heard this nonsence?64-bit mode is almost every time faster (except for some special cases)!
|
I spoke here about the new large instruction format of IA64. Compilers are still not ready to support it, and IA64 is still too much a child. The extended AMD x64 instruction set is much more viable (IA64 is a failure)
Quote:
You completly missed the main-fact why 64-bit mode is a lot faster: more registers. A normal x86 cpu has to live with 8 registers (!!!) whereas 64-bit has 16. This means only 1/2 as much register renaming  |
I can agree with you, but this requires a 64-bit processor runing in 64-bit mode. In 32-bit mode, these extra registers are difficult to use as they are seen as MMX. It's true that the 64-bit mode has unified the set of general, FP and MMX registers (including the stack pointer, frame pointer). Not all those 16 registers are usable for general purpose in practice.
Quote:
|
Hyperthreading is broken by design (TM). Don't you know what hyperthreading is?
|
I know what it is. It allows parallel execution of instructions using two independant sets of registers and parallel pipelines in the same core, and sharing some resources such as the internal cache. It's an intermediate solution before the full dual-core implementation, but it offers interesting optimization (and better usage of energy) which is otherwise more difficult to reach with independant dual cores.
Quote:
|
I would suggest to study computer science or something like that before telling everybody how great and experienced you are.
|
I have studied that and practiced it since long (that's my job).
You don't need to adopt such agressive and negative attitude. I've been polite and respectuous with you, and I expect you'll do the same with me. If there are errors in what I say (nobody's perfect), you can correct things. Please adopt a more neutral style when replying to someone in a public area such as this forum.
There's no need to flame or insult anyone, or even assert things about someone you don't know, such as the type of studies and courses he has followed. Remember that in public groups, we are not required to reveal all our personnal details or history, and reposnes could have been longer to include the details you lack.