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rockbox/firmware/thread.c
Jens Arnold 6d54d6c088 SH1: Tiny optimisation of the thread scheduler. 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7406 a1c6a512-1295-4272-9138-f99709370657
2005-08-26 22:52:31 +00:00

362 lines
11 KiB
C
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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 "config.h"
#include <stdbool.h>
#include "thread.h"
#include "panic.h"
#include "system.h"
#include "kernel.h"
#include "cpu.h"
#ifdef CPU_COLDFIRE
struct regs
{
unsigned int d[6]; /* d2-d7 */
unsigned int a[5]; /* a2-a6 */
void *sp; /* Stack pointer (a7) */
void *start; /* Thread start address, or NULL when started */
};
#elif CONFIG_CPU == SH7034
struct regs
{
unsigned int r[7]; /* Registers r8 thru r14 */
void *sp; /* Stack pointer (r15) */
void *pr; /* Procedure register */
void *start; /* Thread start address, or NULL when started */
};
#elif CONFIG_CPU == TCC730
struct regs
{
void *sp; /* Stack pointer (a15) */
void *start; /* Thread start address */
int started; /* 0 when not started */
};
#endif
#define DEADBEEF ((unsigned int)0xdeadbeef)
/* Cast to the the machine int type, whose size could be < 4. */
int num_threads;
static volatile int num_sleepers;
static int current_thread;
static struct regs thread_contexts[MAXTHREADS] __attribute__ ((section(".idata")));
const char *thread_name[MAXTHREADS];
void *thread_stack[MAXTHREADS];
int thread_stack_size[MAXTHREADS];
static const char main_thread_name[] = "main";
extern int stackbegin[];
extern int stackend[];
void switch_thread(void) __attribute__ ((section(".icode")));
static inline void store_context(void* addr) __attribute__ ((always_inline));
static inline void load_context(const void* addr) __attribute__ ((always_inline));
#ifdef CPU_COLDFIRE
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile (
"movem.l %%d2-%%d7/%%a2-%%a7,(%0)\n"
: : "a" (addr)
);
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(const void* addr)
{
asm volatile (
"movem.l (%0),%%d2-%%d7/%%a2-%%a7\n" /* Load context */
"move.l (48,%0),%%d0 \n" /* Get start address */
"beq.b .running \n" /* NULL -> already running */
"clr.l (48,%0) \n" /* Clear start address.. */
"move.l %%d0,%0 \n"
"jmp (%0) \n" /* ..and start the thread */
".running: \n"
: : "a" (addr) : "d0" /* only! */
);
}
#elif CONFIG_CPU == SH7034
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void store_context(void* addr)
{
asm volatile (
"add #36,%0 \n"
"sts.l pr, @-%0 \n"
"mov.l r15,@-%0 \n"
"mov.l r14,@-%0 \n"
"mov.l r13,@-%0 \n"
"mov.l r12,@-%0 \n"
"mov.l r11,@-%0 \n"
"mov.l r10,@-%0 \n"
"mov.l r9, @-%0 \n"
"mov.l r8, @-%0 \n"
: : "r" (addr)
);
}
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
static inline void load_context(const void* addr)
{
asm volatile (
"mov.l @%0+,r8 \n"
"mov.l @%0+,r9 \n"
"mov.l @%0+,r10 \n"
"mov.l @%0+,r11 \n"
"mov.l @%0+,r12 \n"
"mov.l @%0+,r13 \n"
"mov.l @%0+,r14 \n"
"mov.l @%0+,r15 \n"
"lds.l @%0+,pr \n"
"mov.l @%0,r0 \n" /* Get start address */
"tst r0,r0 \n"
"bt .running \n" /* NULL -> already running */
"lds r0,pr \n"
"mov #0,r0 \n"
"rts \n" /* Start the thread */
"mov.l r0,@%0 \n" /* Clear start address */
".running: \n"
: : "r" (addr) : "r0" /* only! */
);
}
#elif CONFIG_CPU == TCC730
/*---------------------------------------------------------------------------
* Store non-volatile context.
*---------------------------------------------------------------------------
*/
#define store_context(addr) \
__asm__ volatile ( \
"push r0,r1\n\t" \
"push r2,r3\n\t" \
"push r4,r5\n\t" \
"push r6,r7\n\t" \
"push a8,a9\n\t" \
"push a10,a11\n\t" \
"push a12,a13\n\t" \
"push a14\n\t" \
"ldw @[%0+0], a15\n\t" : : "a" (addr) );
/*---------------------------------------------------------------------------
* Load non-volatile context.
*---------------------------------------------------------------------------
*/
#define load_context(addr) \
{ \
if (!(addr)->started) { \
(addr)->started = 1; \
__asm__ volatile ( \
"ldw a15, @[%0+0]\n\t" \
"ldw a14, @[%0+4]\n\t" \
"jmp a14\n\t" : : "a" (addr) \
); \
} else \
__asm__ volatile ( \
"ldw a15, @[%0+0]\n\t" \
"pop a14\n\t" \
"pop a13,a12\n\t" \
"pop a11,a10\n\t" \
"pop a9,a8\n\t" \
"pop r7,r6\n\t" \
"pop r5,r4\n\t" \
"pop r3,r2\n\t" \
"pop r1,r0\n\t" : : "a" (addr) \
); \
\
}
#endif
/*---------------------------------------------------------------------------
* Switch thread in round robin fashion.
*---------------------------------------------------------------------------
*/
void switch_thread(void)
{
int current;
unsigned int *stackptr;
#ifdef SIMULATOR
/* Do nothing */
#else
while (num_sleepers == num_threads)
{
/* Enter sleep mode, woken up on interrupt */
#ifdef CPU_COLDFIRE
asm volatile ("stop #0x2000");
#elif CONFIG_CPU == SH7034
and_b(0x7F, &SBYCR);
asm volatile ("sleep");
#elif CONFIG_CPU == TCC730
/* Sleep mode is triggered by the SYS instr on CalmRisc16.
* Unfortunately, the manual doesn't specify which arg to use.
__asm__ volatile ("sys #0x0f");
0x1f seems to trigger a reset;
0x0f is the only one other argument used by Archos.
*/
#endif
}
#endif
current = current_thread;
store_context(&thread_contexts[current]);
#if CONFIG_CPU != TCC730
/* Check if the current thread stack is overflown */
stackptr = thread_stack[current];
if(stackptr[0] != DEADBEEF)
panicf("Stkov %s", thread_name[current]);
#endif
if (++current >= num_threads)
current = 0;
current_thread = current;
load_context(&thread_contexts[current]);
}
void sleep_thread(void)
{
++num_sleepers;
switch_thread();
}
void wake_up_thread(void)
{
num_sleepers = 0;
}
/*---------------------------------------------------------------------------
* Create thread.
* Return ID if context area could be allocated, else -1.
*---------------------------------------------------------------------------
*/
int create_thread(void (*function)(void), void* stack, int stack_size,
const char *name)
{
unsigned int i;
unsigned int stacklen;
unsigned int *stackptr;
struct regs *regs;
if (num_threads >= MAXTHREADS)
return -1;
/* Munge the stack to make it easy to spot stack overflows */
stacklen = stack_size / sizeof(int);
stackptr = stack;
for(i = 0;i < stacklen;i++)
{
stackptr[i] = DEADBEEF;
}
/* Store interesting information */
thread_name[num_threads] = name;
thread_stack[num_threads] = stack;
thread_stack_size[num_threads] = stack_size;
regs = &thread_contexts[num_threads];
#if defined(CPU_COLDFIRE) || (CONFIG_CPU == SH7034)
/* Align stack to an even 32 bit boundary */
regs->sp = (void*)(((unsigned int)stack + stack_size) & ~3);
#elif CONFIG_CPU == TCC730
/* Align stack on word boundary */
regs->sp = (void*)(((unsigned long)stack + stack_size - 2) & ~1);
regs->started = 0;
#endif
regs->start = (void*)function;
wake_up_thread();
return num_threads++; /* return the current ID, e.g for remove_thread() */
}
/*---------------------------------------------------------------------------
* Remove a thread from the scheduler.
* Parameter is the ID as returned from create_thread().
*---------------------------------------------------------------------------
*/
void remove_thread(int threadnum)
{
int i;
if(threadnum >= num_threads)
return;
num_threads--;
for (i=threadnum; i<num_threads-1; i++)
{ /* move all entries which are behind */
thread_name[i] = thread_name[i+1];
thread_stack[i] = thread_stack[i+1];
thread_stack_size[i] = thread_stack_size[i+1];
thread_contexts[i] = thread_contexts[i+1];
}
if (current_thread == threadnum) /* deleting the current one? */
current_thread = num_threads; /* set beyond last, avoid store harm */
else if (current_thread > threadnum) /* within the moved positions? */
current_thread--; /* adjust it, point to same context again */
}
void init_threads(void)
{
num_threads = 1; /* We have 1 thread to begin with */
current_thread = 0; /* The current thread is number 0 */
thread_name[0] = main_thread_name;
thread_stack[0] = stackbegin;
thread_stack_size[0] = (int)stackend - (int)stackbegin;
#if defined(CPU_COLDFIRE) || (CONFIG_CPU == SH7034)
thread_contexts[0].start = 0; /* thread 0 already running */
#elif CONFIG_CPU == TCC730
thread_contexts[0].started = 1;
#endif
num_sleepers = 0;
}
int thread_stack_usage(int threadnum)
{
unsigned int i;
unsigned int *stackptr = thread_stack[threadnum];
if(threadnum >= num_threads)
return -1;
for(i = 0;i < thread_stack_size[threadnum]/sizeof(int);i++)
{
if(stackptr[i] != DEADBEEF)
break;
}
return ((thread_stack_size[threadnum] - i * sizeof(int)) * 100) /
thread_stack_size[threadnum];
}
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