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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"
struct regs
{
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 */
};
static int num_threads;
static int current_thread;
static struct regs thread_contexts[MAXTHREADS];
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(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 load_context(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 current;
int next;
next = current = current_thread;
if (++next >= num_threads)
next = 0;
current_thread = next;
store_context(&thread_contexts[current]);
load_context(&thread_contexts[next]);
}
/*---------------------------------------------------------------------------
* Create thread.
* Return 0 if context area could be allocated, else -1.
*---------------------------------------------------------------------------
*/
int create_thread(void* function, void* stack, int stack_size)
{
unsigned int i;
unsigned int stacklen;
unsigned int *stackptr;
if (num_threads >= MAXTHREADS)
return -1;
else
{
/* Munge the stack to make it easy to spot stack overflows */
stacklen = stack_size / 4;
stackptr = stack;
for(i = 0;i < stacklen;i++)
{
stackptr[i] = 0xdeadbeef;
}
struct regs* regs = &thread_contexts[num_threads++];
store_context(regs);
/* Subtract 4 to leave room for the PR push in ldctx()
Align it on an even 32 bit boundary */
regs->sp = (void*)(((unsigned int)stack + stack_size - 4) & ~3);
regs->sr = 0;
regs->pr = function;
}
return 0;
}
void init_threads(void)
{
num_threads = 1; /* We have 1 thread to begin with */
current_thread = 0; /* The current thread is number 0 */
}
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