void thread_cleanup( void )
{
head->isTerminated = 1;
if( head->joining != NULL )
{
TCB* temp = head;
head = head->next;
temp->next = NULL;
TCB* cur = head;
while( cur->next != NULL )
cur = cur->next;
cur->next = temp->joining;
asm_yield( NULL, head );
return;
}
else
{
TCB* temp = head;
head = head->next;
temp->next = NULL;
if( nextFreeingStack != NULL )
free( nextFreeingStack );
nextFreeingStack = temp->stk_base;
free( temp );
asm_yield( NULL, head );
}
}
int thread_join(long thread_ID)
{
isCritical = 1;
if( !isCreated )
{
initialize_head( );
}
TCB* cur = (TCB*)thread_ID;
if( cur == NULL )
return -3;
if( cur->joining != NULL )
return -2;
TCB* temp = head;
while( temp != NULL )
{
if( temp == cur )
return -1;
temp = temp->joining;
}
if( !(cur->isTerminated) )
{
TCB* prev = head;
prev = head;
cur->joining = head;
head = head->next;
asm_yield( prev, head );
}
isCritical = 0;
return 0;
}
void thread_yield(void)
{
isCritical = 1;
if( !isCreated )
{
initialize_head( );
}
if( head -> next == NULL )
return;
TCB *temp = head;
head = head->next;
TCB* cur = head;
while( cur->next != NULL )
cur = cur->next;
cur->next = temp;
temp->next = NULL;
asm_yield( temp, head );
isCritical = 0;
}
/*This function moves the current running thread to the end of the ready queue. The new thread at the
head of the queue is given the cpu*/
void thread_yield(void)
{
critFlag = 1;
if(!initDone)
{
doInit();
initDone = 1;
}
// if ready queue is empty, return (how do I check if the ready queue is empty?) head -> next == NULL? end == head?
if(head -> next == NULL)
{
//I want the thread to keep running and simply not yield
return;
}
else
{
//rotate ready queue. first element needs to be at the end and last element needs to be at the beginning
struct TCB * endingVal = head;
struct TCB * p = head -> next;
struct TCB * traverse = head;
while(traverse -> next != NULL)
{
traverse = traverse -> next;
}
traverse -> next = endingVal;
traverse = traverse -> next;
traverse -> next = NULL;
end = traverse;
head = p;
struct TCB * cur = endingVal;
struct TCB * next = head;
//save current thread's state(register contents) in it's TCB and restore the next thread's state from it's TCB
//asm-yield()?
critFlag = 0;
asm_yield(cur, next);
}
}