Subversion Repositories shark

Compare Revisions

Ignore whitespace Rev 1393 → Rev 1392

/demos/trunk/base/pcidemo.c
40,6 → 40,8
 
sleep(5);
sys_end();
return 0;
 
}
/demos/trunk/base/aster6.c
34,7 → 34,7
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* CVS : $Id: aster6.c,v 1.5 2004-04-21 14:55:05 giacomo Exp $
* CVS : $Id: aster6.c,v 1.4 2004-04-17 11:36:12 giacomo Exp $
 
this is a part of the classic Hartik demo Aster.
 
47,6 → 47,8
#include "modules/edf.h"
#include "modules/cbs.h"
 
#include <drivers/shark_linuxc26.h>
#include <drivers/shark_input26.h>
#include <drivers/shark_keyb26.h>
 
int num_aster = 0;
85,6 → 87,60
#define ASTER_WCET 2000 /* 200*/
#endif
 
PID shutdown_task_PID = -1;
 
int device_drivers_init() {
KEYB_PARMS kparms = BASE_KEYB;
LINUXC26_register_module();
 
keyb_def_ctrlC(kparms, NULL);
INPUT26_init();
 
KEYB26_init(&kparms);
 
return 0;
}
 
int device_drivers_close() {
 
KEYB26_close();
 
INPUT26_close();
 
return 0;
 
}
 
TASK shutdown_task_body(void *arg) {
 
device_drivers_close();
 
sys_shutdown_message("-- S.Ha.R.K. Closed --\n");
 
sys_end();
 
return NULL;
 
}
 
void set_shutdown_task() {
 
NRT_TASK_MODEL nrt;
 
nrt_task_default_model(nrt);
 
shutdown_task_PID = task_create("Shutdown Task",shutdown_task_body,&nrt,NULL);
if (shutdown_task_PID == NIL) {
sys_shutdown_message("Error: Cannot create shutdown task\n");
sys_end();
}
 
}
 
TASK asteroide(void)
{
int i;
276,8 → 332,8
while(1) {
mutex_lock(&m1);
printf_xy(62,1,WHITE,"%2d:%2d ast=%d",m,s, num_aster);
printf_xy(62,2,WHITE,"Uedf=%12u",EDF_usedbandwidth(1));
printf_xy(62,4,WHITE,"Ucbs=%12u",CBS_usedbandwidth(3));
printf_xy(62,2,WHITE,"Uedf=%12u",EDF_usedbandwidth(0));
printf_xy(62,4,WHITE,"Ucbs=%12u",CBS_usedbandwidth(2));
 
mutex_unlock(&m1);
 
289,8 → 345,8
}
mutex_lock(&m1);
printf_xy(62,1,WHITE,"%2d:%2d ast=%d",m,s, num_aster);
printf_xy(62,2,WHITE,"Uedf=%12u",EDF_usedbandwidth(1));
printf_xy(62,4,WHITE,"Ucbs=%12u",CBS_usedbandwidth(3));
printf_xy(62,2,WHITE,"Uedf=%12u",EDF_usedbandwidth(0));
printf_xy(62,4,WHITE,"Ucbs=%12u",CBS_usedbandwidth(2));
mutex_unlock(&m1);
task_endcycle();
}
321,7 → 377,7
for (j=0; j<5; j++) last[j] = 0;
jet_gettable(p, &last[0], 5);
mutex_lock(&m1);
if (proc_table[p].task_level == 3)
if (proc_table[p].task_level == 2)
printf_xy(0,STAT_Y+i+1,WHITE,"%-3d ³ %-6d ³ %-6d ³ %-4d ³ %-7d ³ %-5d ³ %-5d ³ %-5d ³ %-5d ³ %-5d",
p, (int)sum/(nact==0 ? 1 : nact), (int)max, nact, (int)CBS_get_nact(2,p), (int)last[0], (int)last[1], (int)last[2], (int)last[3], (int)last[4]);
// p, sum/(nact==0 ? 1 : nact), max, proc_table[p].avail_time, proc_table[p].status, proc_table[p].shadow, proc_table[p].timespec_priority.tv_sec,proc_table[p].timespec_priority.tv_nsec/1000 , CBS_get_nact(2,p), last[4]);
337,9 → 393,7
 
void fine(KEY_EVT *e)
{
 
sys_end();
 
task_activate(shutdown_task_PID);
}
 
int main(int argc, char **argv)
352,6 → 406,10
// int i;
struct timespec fineprg;
 
set_shutdown_task();
 
device_drivers_init();
 
#ifdef PIMUTEX
PI_mutexattr_t a;
#endif
400,7 → 458,7
p1 = task_create("Aster",aster,&m,NULL);
if (p1 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <aster> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
409,7 → 467,7
p2 = task_create("Clock",clock,&m,NULL);
if (p2 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <Clock> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
417,7 → 475,7
p3 = task_create("JetControl",jetcontrol,&m_aper,NULL);
if (p3 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <JetControl> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
437,7 → 495,7
 
mutex_init(&m1, &a);
 
fineprg.tv_sec = 20;
fineprg.tv_sec = 1800;
fineprg.tv_nsec = 0;
kern_event_post(&fineprg,(void (*)(void *))fine,NULL);
group_activate(1);
/demos/trunk/base/aster7.c
34,7 → 34,7
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* CVS : $Id: aster7.c,v 1.4 2004-04-21 14:55:05 giacomo Exp $
* CVS : $Id: aster7.c,v 1.3 2004-04-17 11:36:12 giacomo Exp $
 
this is a part of the classic Hartik demo Aster.
 
74,6 → 74,60
 
PID aper_table[APER_MAX];
 
PID shutdown_task_PID = -1;
 
int device_drivers_init() {
KEYB_PARMS kparms = BASE_KEYB;
LINUXC26_register_module();
 
keyb_def_ctrlC(kparms, NULL);
INPUT26_init();
 
KEYB26_init(&kparms);
 
return 0;
}
 
int device_drivers_close() {
 
KEYB26_close();
 
INPUT26_close();
 
return 0;
 
}
 
TASK shutdown_task_body(void *arg) {
 
device_drivers_close();
 
sys_shutdown_message("-- S.Ha.R.K. Closed --\n");
 
sys_end();
 
return NULL;
 
}
 
void set_shutdown_task() {
 
NRT_TASK_MODEL nrt;
 
nrt_task_default_model(nrt);
 
shutdown_task_PID = task_create("Shutdown Task",shutdown_task_body,&nrt,NULL);
if (shutdown_task_PID == NIL) {
sys_shutdown_message("Error: Cannot create shutdown task\n");
sys_end();
}
 
}
 
TASK asteroide(void)
{
int i;
183,7 → 237,7
 
while(1) {
printf_xy(62,1,WHITE,"%2d:%2d ast=%d",m,s, num_aster);
printf_xy(62,2,WHITE,"U=%12u",EDF_usedbandwidth(1));
printf_xy(62,2,WHITE,"U=%12u",EDF_usedbandwidth(0));
task_endcycle();
 
if (++s > 59) {
191,7 → 245,7
m++;
}
printf_xy(62,1,WHITE,"%2d:%2d ast=%d",m,s, num_aster);
printf_xy(62,2,WHITE,"U=%12u",EDF_usedbandwidth(1));
printf_xy(62,2,WHITE,"U=%12u",EDF_usedbandwidth(0));
task_endcycle();
}
}
231,7 → 285,7
 
void fine(KEY_EVT *e)
{
sys_end();
task_activate(shutdown_task_PID);
}
 
 
243,6 → 297,10
SOFT_TASK_MODEL m_aper;
int i;
 
set_shutdown_task();
 
device_drivers_init();
 
KEY_EVT emerg;
 
clear();
269,7 → 327,7
p1 = task_create("Aster",aster,&m,NULL);
if (p1 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <aster> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
278,19 → 336,19
p2 = task_create("Clock",clock,&m,NULL);
if (p2 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <Clock> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
soft_task_default_model(m_aper);
soft_task_def_ctrl_jet(m_aper);
soft_task_def_level(m_aper, 2);
soft_task_def_level(m_aper, 1);
soft_task_def_group(m_aper,1);
soft_task_def_aperiodic(m_aper);
p3 = task_create("JetControl",jetcontrol,&m_aper,NULL);
if (p3 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <JetControl> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
299,12 → 357,12
soft_task_def_aperiodic(m_aper);
 
for (i=0; i<APER_MAX; i++) {
soft_task_def_level(m_aper, i/4 + 4);
soft_task_def_level(m_aper, i/4 + 3);
soft_task_def_arg(m_aper, (void *)(i/4 ? 'Û' : '±'));
aper_table[i] = task_create("aper",aper_asteroid,&m_aper,NULL);
if (aper_table[i] == -1) {
sys_shutdown_message("test7.c(main): Could not create task <aper> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
}
/demos/trunk/base/aster8.c
34,7 → 34,7
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* CVS : $Id: aster8.c,v 1.4 2004-04-21 14:55:05 giacomo Exp $
* CVS : $Id: aster8.c,v 1.3 2004-04-17 11:36:13 giacomo Exp $
 
Test for Sporadic Server (ss):
 
53,12 → 53,14
#include "modules/cbs.h"
#include "modules/ss.h"
 
#include <drivers/shark_linuxc26.h>
#include <drivers/shark_input26.h>
#include <drivers/shark_keyb26.h>
 
int num_aster = 0;
#define EDF_LEV 1
#define CBS_LEV 2
#define SS_LEV 3
#define EDF_LEV 0
#define CBS_LEV 1
#define SS_LEV 2
 
#define ASTER_LIM 60
#define DISPLAY_MAX 8
97,7 → 99,60
#endif
 
PID p1,p2,p3,p4,p5;
PID shutdown_task_PID = -1;
 
int device_drivers_init() {
KEYB_PARMS kparms = BASE_KEYB;
LINUXC26_register_module();
 
keyb_def_ctrlC(kparms, NULL);
INPUT26_init();
 
KEYB26_init(&kparms);
 
return 0;
}
 
int device_drivers_close() {
 
KEYB26_close();
 
INPUT26_close();
 
return 0;
 
}
 
TASK shutdown_task_body(void *arg) {
 
device_drivers_close();
 
sys_shutdown_message("-- S.Ha.R.K. Closed --\n");
 
sys_end();
 
return NULL;
 
}
 
void set_shutdown_task() {
 
NRT_TASK_MODEL nrt;
 
nrt_task_default_model(nrt);
 
shutdown_task_PID = task_create("Shutdown Task",shutdown_task_body,&nrt,NULL);
if (shutdown_task_PID == NIL) {
sys_shutdown_message("Error: Cannot create shutdown task\n");
sys_end();
}
 
}
 
TASK asteroide(void)
{
int i;
338,7 → 393,7
for (j=0; j<5; j++) last[j] = 0;
jet_gettable(p, &last[0], 5);
mutex_lock(&m1);
if (proc_table[p].task_level == 2)
if (proc_table[p].task_level == 1)
printf_xy(0,STAT_Y+i+1,WHITE,"%-3d ³ %-6d ³ %-6d ³ %-4d ³ %-7d ³ %-5d ³ %-5d ³ %-5d ³ %-5d ³ %-5d",
p, (int)sum/(nact==0 ? 1 : nact), (int)max, nact, (int)CBS_get_nact(2,p), (int)last[0], (int)last[1], (int)last[2], (int)last[3], (int)last[4]);
// p, sum/(nact==0 ? 1 : nact), max, proc_table[p].avail_time, proc_table[p].status, proc_table[p].shadow, proc_table[p].timespec_priority.tv_sec,proc_table[p].timespec_priority.tv_nsec/1000 , CBS_get_nact(2,p), last[4]);
356,9 → 411,7
 
void fine(KEY_EVT *e)
{
 
sys_end();
 
task_activate(shutdown_task_PID);
}
 
void mydummyaper(void) {
389,6 → 442,10
SOFT_TASK_MODEL m_aper;
SOFT_TASK_MODEL m_soft;
 
set_shutdown_task();
 
device_drivers_init();
 
#ifdef PIMUTEX
PI_mutexattr_t a;
#endif
443,7 → 500,7
p1 = task_create("Aster",aster,&m,NULL);
if (p1 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <aster> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
452,7 → 509,7
p2 = task_create("Clock",clock,&m,NULL);
if (p2 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <Clock> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
459,7 → 516,7
p3 = task_create("JetControl",jetcontrol,&m_aper,NULL);
if (p3 == -1) {
sys_shutdown_message("test7.c(main): Could not create task <JetControl> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
466,7 → 523,7
p4 = task_create("MyDummyAper",(void *(*)(void*))mydummyaper,&m_aper,NULL);
if (p4 == -1) {
sys_shutdown_message("Could not create task <MyDummyAper> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
473,7 → 530,7
p5 = task_create("MyDummyNRT",(void *(*)(void*))mydummynrt,&m_nrt,NULL);
if (p5 == -1) {
sys_shutdown_message("Could not create task <MyDummyNRT> ...");
sys_end();
task_activate(shutdown_task_PID);
return 0;
}
 
/demos/trunk/base/iaster6.c
18,11 → 18,11
 
/**
------------
CVS : $Id: iaster6.c,v 1.3 2004-04-21 14:55:05 giacomo Exp $
CVS : $Id: iaster6.c,v 1.2 2004-04-17 11:36:13 giacomo Exp $
 
File: $File$
Revision: $Revision: 1.3 $
Last update: $Date: 2004-04-21 14:55:05 $
Revision: $Revision: 1.2 $
Last update: $Date: 2004-04-17 11:36:13 $
------------
 
System initialization file
85,10 → 85,6
#include "modules/npp.h"
#include "modules/nop.h"
 
#include <drivers/shark_linuxc26.h>
#include <drivers/shark_input26.h>
#include <drivers/shark_keyb26.h>
 
/*+ sysyem tick in us +*/
#define TICK 1000
 
100,14 → 96,6
#define INTDRIVE_T 10000
#define INTDRIVE_FLAG 0
 
void call_shutdown_task(void *arg);
int device_drivers_init();
int device_drivers_close();
void set_shutdown_task();
TASK shutdown_task_body(void *arg);
 
PID shutdown_task_PID = 1;
 
TIME __kernel_register_levels__(void *arg)
{
struct multiboot_info *mb = (struct multiboot_info *)arg;
138,89 → 126,8
 
HARTPORT_init();
 
/* Create the shutdown task. It will be activated at RUNLEVEL
SHUTDOWN */
set_shutdown_task();
 
/* Init the drivers */
device_drivers_init();
 
/* Set the shutdown task activation */
sys_atrunlevel(call_shutdown_task, NULL, RUNLEVEL_SHUTDOWN);
 
__call_main__(mb);
 
return (void *)0;
}
 
void set_shutdown_task() {
 
/* WARNING: the shutdown task is a background thread. It cannot execute
if the system is overloaded */
NRT_TASK_MODEL nrt;
 
nrt_task_default_model(nrt);
nrt_task_def_system(nrt);
 
shutdown_task_PID = task_create("Shutdown Task",shutdown_task_body,&nrt,NULL);
if (shutdown_task_PID == NIL) {
sys_shutdown_message("Error: Cannot create shutdown task\n");
sys_end();
}
 
}
 
int device_drivers_init() {
 
KEYB_PARMS kparms = BASE_KEYB;
LINUXC26_register_module();
 
INPUT26_init();
 
keyb_def_ctrlC(kparms, NULL);
 
KEYB26_init(&kparms);
 
return 0;
 
}
 
int device_drivers_close() {
KEYB26_close();
INPUT26_close();
return 0;
}
 
#define SHUTDOWN_TIMEOUT_SEC 3
 
void call_shutdown_task(void *arg)
{
struct timespec t;
 
sys_gettime(&t);
t.tv_sec += SHUTDOWN_TIMEOUT_SEC;
 
/* Emergency timeout to exit from RUNLEVEL_SHUTDOWN */
kern_event_post(&t,(void *)((void *)sys_abort_shutdown),(void *)0);
 
task_activate(shutdown_task_PID);
}
 
TASK shutdown_task_body(void *arg) {
 
device_drivers_close();
 
sys_shutdown_message("-- S.Ha.R.K. Closed --\n");
 
sys_abort_shutdown(0);
 
return NULL;
 
}
 
 
/demos/trunk/base/iaster7.c
18,11 → 18,11
 
/**
------------
CVS : $Id: iaster7.c,v 1.3 2004-04-21 14:55:06 giacomo Exp $
CVS : $Id: iaster7.c,v 1.2 2004-04-17 11:36:13 giacomo Exp $
 
File: $File$
Revision: $Revision: 1.3 $
Last update: $Date: 2004-04-21 14:55:06 $
Revision: $Revision: 1.2 $
Last update: $Date: 2004-04-17 11:36:13 $
------------
 
System initialization file
78,10 → 78,6
#include "modules/sem.h"
#include "modules/hartport.h"
 
#include <drivers/shark_linuxc26.h>
#include <drivers/shark_input26.h>
#include <drivers/shark_keyb26.h>
 
/*+ sysyem tick in us +*/
#define TICK 0
 
92,14 → 88,6
#define INTDRIVE_T 10000
#define INTDRIVE_FLAG 0
 
void call_shutdown_task(void *arg);
int device_drivers_init();
int device_drivers_close();
void set_shutdown_task();
TASK shutdown_task_body(void *arg);
 
PID shutdown_task_PID = 1;
 
TIME __kernel_register_levels__(void *arg)
{
struct multiboot_info *mb = (struct multiboot_info *)arg;
124,91 → 112,8
 
HARTPORT_init();
 
/* Create the shutdown task. It will be activated at RUNLEVEL
SHUTDOWN */
set_shutdown_task();
 
/* Init the drivers */
device_drivers_init();
 
/* Set the shutdown task activation */
sys_atrunlevel(call_shutdown_task, NULL, RUNLEVEL_SHUTDOWN);
 
__call_main__(mb);
 
return (void *)0;
}
 
void set_shutdown_task() {
 
/* WARNING: the shutdown task is a background thread. It cannot execute
if the system is overloaded */
NRT_TASK_MODEL nrt;
 
nrt_task_default_model(nrt);
nrt_task_def_system(nrt);
 
shutdown_task_PID = task_create("Shutdown Task",shutdown_task_body,&nrt,NULL);
if (shutdown_task_PID == NIL) {
sys_shutdown_message("Error: Cannot create shutdown task\n");
sys_end();
}
 
}
 
int device_drivers_init() {
 
KEYB_PARMS kparms = BASE_KEYB;
LINUXC26_register_module();
 
INPUT26_init();
 
keyb_def_ctrlC(kparms, NULL);
 
KEYB26_init(&kparms);
 
return 0;
 
}
 
int device_drivers_close() {
KEYB26_close();
INPUT26_close();
return 0;
}
 
#define SHUTDOWN_TIMEOUT_SEC 3
 
void call_shutdown_task(void *arg)
{
struct timespec t;
 
sys_gettime(&t);
t.tv_sec += SHUTDOWN_TIMEOUT_SEC;
 
/* Emergency timeout to exit from RUNLEVEL_SHUTDOWN */
kern_event_post(&t,(void *)((void *)sys_abort_shutdown),(void *)0);
 
task_activate(shutdown_task_PID);
}
 
TASK shutdown_task_body(void *arg) {
 
device_drivers_close();
 
sys_shutdown_message("-- S.Ha.R.K. Closed --\n");
 
sys_abort_shutdown(0);
 
return NULL;
 
}
 
 
 
 
/demos/trunk/base/iaster8.c
18,11 → 18,11
 
/**
------------
CVS : $Id: iaster8.c,v 1.3 2004-04-21 14:55:06 giacomo Exp $
CVS : $Id: iaster8.c,v 1.2 2004-04-17 11:36:13 giacomo Exp $
 
File: $File$
Revision: $Revision: 1.3 $
Last update: $Date: 2004-04-21 14:55:06 $
Revision: $Revision: 1.2 $
Last update: $Date: 2004-04-17 11:36:13 $
------------
 
System initialization file
85,10 → 85,6
#include "modules/npp.h"
#include "modules/nop.h"
 
#include <drivers/shark_linuxc26.h>
#include <drivers/shark_input26.h>
#include <drivers/shark_keyb26.h>
 
/*+ system tick in us +*/
#define TICK 1000
 
100,14 → 96,6
#define INTDRIVE_T 10000
#define INTDRIVE_FLAG 0
 
void call_shutdown_task(void *arg);
int device_drivers_init();
int device_drivers_close();
void set_shutdown_task();
TASK shutdown_task_body(void *arg);
 
PID shutdown_task_PID = 1;
 
TIME __kernel_register_levels__(void *arg)
{
struct multiboot_info *mb = (struct multiboot_info *)arg;
114,8 → 102,8
 
INTDRIVE_register_level(INTDRIVE_Q,INTDRIVE_T,INTDRIVE_FLAG);
EDF_register_level(EDF_ENABLE_ALL);
CBS_register_level(CBS_ENABLE_ALL, 1);
SS_register_level(SS_ENABLE_GUARANTEE_EDF,1,5000,20000);
CBS_register_level(CBS_ENABLE_ALL, 0);
SS_register_level(SS_ENABLE_GUARANTEE_EDF,0,5000,20000);
RR_register_level(RRTICK, RR_MAIN_YES, mb);
dummy_register_level();
 
137,92 → 125,9
struct multiboot_info *mb = (struct multiboot_info *)arg;
 
HARTPORT_init();
 
/* Create the shutdown task. It will be activated at RUNLEVEL
SHUTDOWN */
set_shutdown_task();
 
/* Init the drivers */
device_drivers_init();
 
/* Set the shutdown task activation */
sys_atrunlevel(call_shutdown_task, NULL, RUNLEVEL_SHUTDOWN);
 
__call_main__(mb);
 
return (void *)0;
}
 
void set_shutdown_task() {
 
/* WARNING: the shutdown task is a background thread. It cannot execute
if the system is overloaded */
NRT_TASK_MODEL nrt;
 
nrt_task_default_model(nrt);
nrt_task_def_system(nrt);
 
shutdown_task_PID = task_create("Shutdown Task",shutdown_task_body,&nrt,NULL);
if (shutdown_task_PID == NIL) {
sys_shutdown_message("Error: Cannot create shutdown task\n");
sys_end();
}
 
}
 
int device_drivers_init() {
 
KEYB_PARMS kparms = BASE_KEYB;
LINUXC26_register_module();
 
INPUT26_init();
 
keyb_def_ctrlC(kparms, NULL);
 
KEYB26_init(&kparms);
 
return 0;
 
}
 
int device_drivers_close() {
KEYB26_close();
INPUT26_close();
return 0;
}
 
#define SHUTDOWN_TIMEOUT_SEC 3
 
void call_shutdown_task(void *arg)
{
struct timespec t;
 
sys_gettime(&t);
t.tv_sec += SHUTDOWN_TIMEOUT_SEC;
 
/* Emergency timeout to exit from RUNLEVEL_SHUTDOWN */
kern_event_post(&t,(void *)((void *)sys_abort_shutdown),(void *)0);
 
task_activate(shutdown_task_PID);
}
 
TASK shutdown_task_body(void *arg) {
 
device_drivers_close();
 
sys_shutdown_message("-- S.Ha.R.K. Closed --\n");
 
sys_abort_shutdown(0);
 
return NULL;
 
}