Damien Neil <[EMAIL PROTECTED]> wrote:
The JVM is a stack machine. JVM opcodes operate on the stack, not on
main memory. The stack is thread-local. In order for a thread to operate
on a variable, therefore, it must first copy it from main store to thread-
local store (the stack).
Silly me, yes of course, that's it.
Parrot, so far as I know, operates in exactly the same way, except that
the thread-local store is a set of registers rather than a stack.
Except that we don't need this mulit-step variable access, because a
P-register can refer to a shared PMC living in a different thread, which
is a different threads interpreter->arena_base memory.
But just like a P-register, a Java stack entry can hold a reference to an object, and in Java there's no thread-based ownership if objects.
So if this parallel is correct, then Java wouldn't need 2-step access either. This is part of why I think this is the wrong interpretation of the JVM spec.
JEff
