3f9c7c2ab5
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@1183 a1c6a512-1295-4272-9138-f99709370657
121 lines
4 KiB
C
121 lines
4 KiB
C
/***************************************************************************
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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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struct regs
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{
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unsigned int r[7]; /* Registers r8 thru r14 */
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void *sp; /* Stack pointer (r15) */
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unsigned int mach;
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unsigned int macl;
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unsigned int sr; /* Status register */
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void* pr; /* Procedure register */
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};
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static int num_threads;
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static int current_thread;
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static struct regs thread_contexts[MAXTHREADS];
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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 store_context(void* addr)
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{
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asm volatile ("add #48, %0\n\t"
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"sts.l pr, @-%0\n\t"
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"stc.l sr, @-%0\n\t"
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"sts.l macl,@-%0\n\t"
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"sts.l mach,@-%0\n\t"
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"mov.l r15, @-%0\n\t"
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"mov.l r14, @-%0\n\t"
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"mov.l r13, @-%0\n\t"
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"mov.l r12, @-%0\n\t"
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"mov.l r11, @-%0\n\t"
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"mov.l r10, @-%0\n\t"
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"mov.l r9, @-%0\n\t"
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"mov.l r8, @-%0" : : "r" (addr));
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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 load_context(void* addr)
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{
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asm volatile ("mov.l @%0+,r8\n\t"
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"mov.l @%0+,r9\n\t"
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"mov.l @%0+,r10\n\t"
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"mov.l @%0+,r11\n\t"
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"mov.l @%0+,r12\n\t"
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"mov.l @%0+,r13\n\t"
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"mov.l @%0+,r14\n\t"
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"mov.l @%0+,r15\n\t"
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"lds.l @%0+,mach\n\t"
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"lds.l @%0+,macl\n\t"
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"ldc.l @%0+,sr\n\t"
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"mov.l @%0,%0\n\t"
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"lds %0,pr\n\t"
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"mov.l %0, @(0, r15)" : "+r" (addr));
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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 switch_thread(void)
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{
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int current;
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int next;
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next = current = current_thread;
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if (++next >= num_threads)
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next = 0;
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current_thread = next;
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store_context(&thread_contexts[current]);
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load_context(&thread_contexts[next]);
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}
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/*---------------------------------------------------------------------------
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* Create thread.
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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 create_thread(void* function, void* stack, int stack_size)
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{
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if (num_threads >= MAXTHREADS)
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return -1;
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else
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{
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struct regs* regs = &thread_contexts[num_threads++];
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store_context(regs);
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/* Subtract 4 to leave room for the PR push in ldctx()
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Align it on an even 32 bit boundary */
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regs->sp = (void*)(((unsigned int)stack + stack_size - 4) & ~3);
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regs->sr = 0;
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regs->pr = function;
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}
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return 0;
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}
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void init_threads(void)
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{
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num_threads = 1; /* We have 1 thread to begin with */
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current_thread = 0; /* The current thread is number 0 */
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}
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