127 lines
4 KiB
C
127 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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typedef union
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{
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struct regs_t
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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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} regs;
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unsigned int mem[12];
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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];
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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 stctx(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 ldctx(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
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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.
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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* fp, void* sp, 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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/* 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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ctxp->regs.sp = (void*)(((unsigned int)sp + stk_size - 4) & ~3);
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ctxp->regs.pr = fp;
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}
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return 0;
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}
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