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Implement cooperative threads on hosted platforms using C code.

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This replaces SDL threads with real cooperative threads, which are less cpu intensive and allow priority scheduling.
The backend for context switching is dependant on the host (sigaltstack/longjmp on Unix, Fibers on Windows).
configure has options to force or disallow SDL threads.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29327 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thomas Martitz 2011-02-18 22:46:01 +00:00
parent 3926c30705
commit 6d85de3419
13 changed files with 580 additions and 27 deletions
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85
firmware/target/hosted/thread-win32.c Normal file
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2010 by Thomas Martitz
*
* Generic ARM threading support
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <windows.h>
#include "system.h"
#define INIT_MAIN_THREAD
#define THREAD_STARTUP_INIT(core, thread, function) \
({ (thread)->context.stack_size = (thread)->stack_size, \
(thread)->context.stack = (uintptr_t)(thread)->stack; \
(thread)->context.start = function; })
static void init_main_thread(void *addr)
{
struct regs *context = (struct regs*)addr;
/* we must convert the current main thread to a fiber to be able to
* schedule other fibers */
context->uc = ConvertThreadToFiber(NULL);
context->stack_size = 0;
}
static inline void store_context(void* addr)
{
(void)addr;
/* nothing to do here, Fibers continue after the SwitchToFiber call */
}
static void start_thread(void)
{
void (*func)(void) = GetFiberData();
func();
/* go out if thread function returns */
thread_exit();
}
/*
* Load context and run it
*
* Resume execution from the last load_context call for the thread
*/
static inline void load_context(const void* addr)
{
struct regs *context = (struct regs*)addr;
if (UNLIKELY(context->start))
{ /* need setup before switching to it */
context->uc = CreateFiber(context->stack_size,
(LPFIBER_START_ROUTINE)start_thread, context->start);
/* can't assign stack pointer, only stack size */
context->stack_size = 0;
context->start = NULL;
}
SwitchToFiber(context->uc);
}
/*
* play nice with the host and sleep while waiting for the tick */
static inline void core_sleep(void)
{
enable_irq();
wait_for_interrupt();
}