Was this question too technical for this group? : Is the %ESP register special?
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> Using assembler in debian on an intel platform.
> Is the %ESP register special in any way (except, of course,
> ist use in the POP and PUSH istructions and their friends.)
> Let me clarify.
> On VMS (old VAX OS), the convnetion was that any data on the stack
> above the stacp poibter was forfeit -- at any time tod OS could
> come in and clobber it, even *during* instruction execution.
> Firthermore, the value of the stack pointer clued in the OS as to whether
> it chould create new pages to handle a page-fault exception, thereby
> extending the stack.
> As a result, if you used the stack pointer for anything other than
> pointing to the top of the stack, even momentarily, you were in deep,
> deep trouble.
> Are there similar OS constraints imposed by the Linux kernel? How do
> pages get allocated to the stack, for example. Is the user's %ESP
> used in any way for this? Can I make any use of %ESP that I want?
> For example, can I allocate a lot of mini-stacks in garbage-collected
> storage to handle, say, a coroutine system, without interference?
> (And yes, it's a compressing garbage-collector. The stacks will
> move around every time garbage-collection occurs.)
> -- hendrik