simple collaborate multitasking scheduler donated to us by Ulf Ralberg
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@170 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Daniel Stenberg
parent
7503957187
commit
3c031c5ab9
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/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Ulf Ralberg
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "thread.h"
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typedef union
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{
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struct regs_t
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{
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void* lr;
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u_int32_t cr;
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void* sp;
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} regs;
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u_int32_t mem[32];
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} ctx_t;
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typedef struct
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{
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int created;
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int current;
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ctx_t ctx[MAXTHREADS] __attribute__ ((aligned (32)));
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} thread_t;
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static thread_t threads = {1, 0};
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/*---------------------------------------------------------------------------
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* Store non-volatile context.
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*---------------------------------------------------------------------------
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*/
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static inline void
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stctx(void* addr)
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{
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u_int32_t tmp;
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__asm__ __volatile__ ("mflr %0" : "=r" (tmp));
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__asm__ __volatile__ ("stw %0,0(%1)" :: "r" (tmp), "b" (addr) : "memory");
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__asm__ __volatile__ ("mfcr %0" : "=r" (tmp));
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__asm__ __volatile__ ("stw %0,4(%1)" :: "r" (tmp), "b" (addr) : "memory");
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__asm__ __volatile__ ("stw 1, 8(%0)\n\t"
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"stw 2, 12(%0)\n\t"
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"stw 13,16(%0)\n\t"
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"stw 14,20(%0)\n\t"
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"stw 15,24(%0)\n\t"
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"stw 16,28(%0)\n\t"
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"stw 17,32(%0)\n\t"
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"stw 18,36(%0)\n\t"
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"stw 19,40(%0)\n\t"
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"stw 20,44(%0)\n\t"
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"stw 21,48(%0)\n\t"
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"stw 22,52(%0)\n\t"
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"stw 23,56(%0)\n\t"
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"stw 24,60(%0)\n\t"
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"stw 25,64(%0)\n\t"
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"stw 26,68(%0)\n\t"
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"stw 27,72(%0)\n\t"
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"stw 28,76(%0)\n\t"
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"stw 29,80(%0)\n\t"
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"stw 30,84(%0)\n\t"
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"stw 31,88(%0)\n\t"
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:: "b" (addr) : "memory");
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}
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/*---------------------------------------------------------------------------
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* Load non-volatile context.
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*---------------------------------------------------------------------------
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*/
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static inline void
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ldctx(void* addr)
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{
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u_int32_t tmp;
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__asm__ __volatile__ ("lwz %0,0(%1)" : "=r" (tmp): "b" (addr) : "memory");
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__asm__ __volatile__ ("mtlr %0" : "=r" (tmp));
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__asm__ __volatile__ ("lwz %0,4(%1)" : "=r" (tmp): "b" (addr) : "memory");
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__asm__ __volatile__ ("mtcr %0" : "=r" (tmp));
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__asm__ __volatile__ ("lwz 1, 8(%0)\n\t"
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"lwz 2, 12(%0)\n\t"
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"lwz 13,16(%0)\n\t"
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"lwz 14,20(%0)\n\t"
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"lwz 15,24(%0)\n\t"
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"lwz 16,28(%0)\n\t"
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"lwz 17,32(%0)\n\t"
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"lwz 18,36(%0)\n\t"
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"lwz 19,40(%0)\n\t"
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"lwz 20,44(%0)\n\t"
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"lwz 21,48(%0)\n\t"
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"lwz 22,52(%0)\n\t"
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"lwz 23,56(%0)\n\t"
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"lwz 24,60(%0)\n\t"
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"lwz 25,64(%0)\n\t"
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"lwz 26,68(%0)\n\t"
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"lwz 27,72(%0)\n\t"
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"lwz 28,76(%0)\n\t"
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"lwz 29,80(%0)\n\t"
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"lwz 30,84(%0)\n\t"
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"lwz 31,88(%0)\n\t"
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:: "b" (addr) : "memory");
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}
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/*---------------------------------------------------------------------------
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* Switch thread in round robin fashion.
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*---------------------------------------------------------------------------
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*/
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void
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switch_thread(void)
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{
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int ct;
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int nt;
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thread_t* t = &threads;
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nt = ct = t->current;
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if (++nt >= t->created)
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nt = 0;
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t->current = nt;
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stctx(&t->ctx[ct]);
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ldctx(&t->ctx[nt]);
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}
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/*---------------------------------------------------------------------------
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* Create thread. Stack is aligned at 32 byte boundary to fit cache line.
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* > 220 bytes allocated on top for exception handlers as per EABI spec.
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* Return 0 if context area could be allocated, else -1.
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*---------------------------------------------------------------------------
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*/
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int
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create_thread(void* fp,
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void* sp,
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int stk_size)
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{
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thread_t* t = &threads;
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if (t->created >= MAXTHREADS)
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return -1;
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else
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{
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ctx_t* ctxp = &t->ctx[t->created++];
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stctx(ctxp);
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ctxp->regs.sp = (void*)(((u_int32_t)sp + stk_size - 256) & ~31);
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ctxp->regs.lr = fp;
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}
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return 0;
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}
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/* eof */
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@ -0,0 +1,32 @@
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/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Ulf Ralberg
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef __thread_h
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#define __thread_h 1
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#include <sys/types.h>
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#define MAXTHREADS 16
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extern int create_thread(void* fp, void* sp, int stk_size);
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extern void switch_thread(void);
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#endif /* __thread.h */
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/* eof */
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