Re: [Boost-users] [coroutine] Assembler snippet for linux x86_64

Subject: Re: [Boost-users] [coroutine] Assembler snippet for linux x86_64
From: Zeljko Vrba (zvrba_at_[hidden])
Date: 2009-07-21 09:40:19

On Tue, Jul 21, 2009 at 03:57:33PM +0400, Pavel Shevaev wrote:
> > However trying to build it on x86_64 gave me a compile time error -
> > "This file is for x86 CPUs only" in swapcontext.cpp, since there is a
> > #if !defined(i386) guard which produces this error.
> 
> Sorry, folks, I'm replying to myself - the problem was gone once I
> excluded swapcontext.cpp from my custom build process. Looks like
> coroutine cleverly fallbacks to POSIX makecontext and friends for
> anything non-linux-x86. Anyway, I believe it would be great to support
> linux x86_64 with a faster assembler implementation of swapcontext.
> I'll play around with the code and report back(if I'm lucky :) )
> 

Download this code:
http://simula.no/research/networks/software/nornir.tar.bz2/view
(all files are under the same license as written in the COPYRIGHT file in
the top-level directory)

The functions you're after are:
ctx_init_internal() and ctx_swap_internal() in nornir/kahn/ctx_amd64.S.
For each new coroutine, you have to manually allocate context and stack;
for an example of how this is done, see the ctx_make() function in 
platform_ux.cc.  The ''main'' coroutine needs just the space for saving
the registers, as the OS takes care of allocating the stack.  The *_internal()
functions operate just on the regs field of the mctx_t structure defined in
platform_ux.h.  The ctx_init() function takes the TOP address of the stack, as
it grows down on AMD64.

This should be enough to get you started with integrating the code in
boost.coroutine; if you have some questions, just ask.