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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "thread.h"
typedef union
{
struct regs_t
{
unsigned int r[7]; /* Registers r8 thru r14 */
void *sp; /* Stack pointer (r15) */
unsigned int mach;
unsigned int macl;
unsigned int sr; /* Status register */
void* pr; /* Procedure register */
} regs;
unsigned int mem[12];
} ctx_t;
typedef struct
{
int created;
int current;
ctx_t ctx[MAXTHREADS] __attribute__ ((aligned (32)));
} thread_t;
static thread_t threads = {1, 0};
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void stctx(void* addr)
{
asm volatile ("add #48, %0\n\t"
"sts.l pr, @-%0\n\t"
"stc.l sr, @-%0\n\t"
"sts.l macl,@-%0\n\t"
"sts.l mach,@-%0\n\t"
"mov.l r15, @-%0\n\t"
"mov.l r14, @-%0\n\t"
"mov.l r13, @-%0\n\t"
"mov.l r12, @-%0\n\t"
"mov.l r11, @-%0\n\t"
"mov.l r10, @-%0\n\t"
"mov.l r9, @-%0\n\t"
"mov.l r8, @-%0" : : "r" (addr));
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void ldctx(void* addr)
{
asm volatile ("mov.l @%0+,r8\n\t"
"mov.l @%0+,r9\n\t"
"mov.l @%0+,r10\n\t"
"mov.l @%0+,r11\n\t"
"mov.l @%0+,r12\n\t"
"mov.l @%0+,r13\n\t"
"mov.l @%0+,r14\n\t"
"mov.l @%0+,r15\n\t"
"lds.l @%0+,mach\n\t"
"lds.l @%0+,macl\n\t"
"ldc.l @%0+,sr\n\t"
"mov.l @%0,%0\n\t"
"lds %0,pr\n\t"
"mov.l %0, @(0, r15)" : "+r" (addr));
}
/*---------------------------------------------------------------------------
* Switch thread in round robin fashion.
*---------------------------------------------------------------------------
*/
void
switch_thread(void)
{
int ct;
int nt;
thread_t* t = &threads;
nt = ct = t->current;
if (++nt >= t->created)
nt = 0;
t->current = nt;
stctx(&t->ctx[ct]);
ldctx(&t->ctx[nt]);
}
/*---------------------------------------------------------------------------
* Create thread. Stack is aligned at 32 byte boundary to fit cache line.
* > 220 bytes allocated on top for exception handlers as per EABI spec.
* Return 0 if context area could be allocated, else -1.
*---------------------------------------------------------------------------
*/
int create_thread(void* fp, void* sp, int stk_size)
{
thread_t* t = &threads;
if (t->created >= MAXTHREADS)
return -1;
else
{
ctx_t* ctxp = &t->ctx[t->created++];
stctx(ctxp);
ctxp->regs.sp = (void*)(((unsigned int)sp + stk_size) & ~31);
ctxp->regs.pr = fp;
}
return 0;
}
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