/**
* Start the OS. First check to see if we are running with the correct stack
* pointer set (PSP) and privilege mode (PRIV).
*
*
* @return os_error_t
*/
os_error_t
os_arch_os_start(void)
{
os_error_t err;
err = OS_ERR_IN_ISR;
if (__get_IPSR() == 0) {
/*
* The following switch statement is really just a sanity check to
* insure that the os initialization routine was called prior to the
* os start routine.
*/
err = OS_OK;
switch (__get_CONTROL() & 0x03) {
/*
* These two cases are for completeness. Thread mode should be set
* to use PSP already.
*
* Fall-through intentional!
*/
case 0x00:
case 0x01:
err = OS_ERR_PRIV;
break;
case 0x02:
/*
* We are running in Privileged Thread mode w/SP = PSP but we
* are supposed to be un-privileged.
*/
if ((os_flags & 1) == OS_RUN_UNPRIV) {
err = OS_ERR_PRIV;
}
break;
case 0x03:
/*
* We are running in Unprivileged Thread mode w/SP = PSP but we
* are supposed to be privileged.
*/
if ((os_flags & 1) == OS_RUN_PRIV) {
err = OS_ERR_PRIV;
}
break;
}
if (err == OS_OK) {
/* Always start OS through SVC call */
svc_os_arch_start();
}
}
return err;
}
/**
* Start the OS. First check to see if we are running with the correct stack
* pointer set (PSP) and privilege mode (PRIV).
*
* @return os_error_t
*/
os_error_t
os_arch_os_start(void)
{
os_error_t err;
/*
* Set the os environment. This will set stack pointers and, based
* on the contents of os_flags, will determine if the tasks run in
* priviliged or un-privileged mode.
*
* We switch to using "empty" part of idle task's stack until
* the svc_os_arch_start() executes SVC, and we will never return.
*/
os_set_env(g_idle_task.t_stackptr - 1);
err = OS_ERR_IN_ISR;
if (__get_IPSR() == 0) {
/*
* The following switch statement is really just a sanity check to
* insure that the os initialization routine was called prior to the
* os start routine.
*/
err = OS_OK;
switch (__get_CONTROL() & 0x03) {
/*
* These two cases are for completeness. Thread mode should be set
* to use PSP already.
*
* Fall-through intentional!
*/
case 0x00:
case 0x01:
err = OS_ERR_PRIV;
break;
case 0x02:
/*
* We are running in Privileged Thread mode w/SP = PSP but we
* are supposed to be un-privileged.
*/
if ((os_flags & 1) == OS_RUN_UNPRIV) {
err = OS_ERR_PRIV;
}
break;
case 0x03:
/*
* We are running in Unprivileged Thread mode w/SP = PSP but we
* are supposed to be privileged.
*/
if ((os_flags & 1) == OS_RUN_PRIV) {
err = OS_ERR_PRIV;
}
break;
}
if (err == OS_OK) {
/* Always start OS through SVC call */
svc_os_arch_start();
}
}
return err;
}
