[COMMIT] Parrot_Context

I added the Parrot_Context struct and inlined all regs and stacks
into it. The save/restore context routines simply copy it in 1 swoop.

Since context switches are not the norm (and register/stack accesses _are_)
we decided to use a memcpy to switch them rather than using a
pointer to a context. Using a pointer would slow down the common cases
of access due to an extra dereference.

    interpreter->ctx->int_reg.registers

and would also kill the current JIT design.

So we end up:

    interpreter->int_reg.registers[0]
    interpreter->user_stack

changes to:

    interpreter->ctx.int_reg.registers[0]
    interpreter->ctx.user_stack

Also, keep in mind, save_context currently sets COW on stacks, and
will eventually do the same for register frames.

This is only important for co-routines and continuations. Common subs
shouldn't need to switch in their own context.

[large patch omitted, see cvs-parrot@perl.org]

-Melvin

• [COMMIT] Parrot_Context by Melvin Smith
• Re: [COMMIT] Parrot_Context by Jerome Vouillon
• Re: [COMMIT] Parrot_Context by Daniel Grunblatt
• Re: [COMMIT] Parrot_Context by dan
• Re: [COMMIT] Parrot_Context by Melvin Smith