// ******** OS_Suspend ************
// suspend execution of currently running thread
// scheduler will choose another thread to execute
// Can be used to implement cooperative multitasking
// Same function as OS_Sleep(0)
// input: none
// output: none
void OS_Suspend(void) {
long curPriority;
unsigned long curTimeSlice;
volatile int i;
OS_DisableInterrupts();
// Determines NextPt
Scheduler();
// Get priority of next thread and calculate timeslice
curPriority = (*NextPt).priority;
curTimeSlice = calcTimeSlice(curPriority);
// Sets next systick period, does not rest counting
SysTickPeriodSet(curTimeSlice);
// Write to register forces systick to reset counting
NVIC_ST_CURRENT_R = 0;
IntPendSet(FAULT_PENDSV);
OS_EnableInterrupts();
return;
}
BOOL FIFO_Get(TFIFO * const FIFO, uint8_t * const dataPtr)
{
OS_DisableInterrupts(); //Enter Critical Section
if (FIFO->NbBytes != 0)
{
FIFO->NbBytes--;
*dataPtr = FIFO->Buffer[FIFO->Start];
FIFO->Start = (FIFO->Start + 1) % FIFO_SIZE;
OS_EnableInterrupts();
return (bTRUE);
}
OS_EnableInterrupts();
return (bFALSE);
}
BOOL FIFO_Put(TFIFO * const FIFO, const uint8_t data)
{
OS_DisableInterrupts(); //Enter Critical Section
if (FIFO->NbBytes < FIFO_SIZE) //Ensure that the buffer is not full before putting data within it
{
FIFO->NbBytes++; //Increment data counter
FIFO->Buffer[FIFO->End] = data; //Store data in the buffer
FIFO->End = (FIFO->End + 1) % FIFO_SIZE; //increment end pointer within FIFO_SIZE
OS_EnableInterrupts();
return (bTRUE);
}
OS_EnableInterrupts();
return (bFALSE);
}
// ******** OS_Sleep ************
// place this thread into a dormant state
// input: number of msec to sleep
// output: none
// You are free to select the time resolution for this function
// Sleep time is a multiple of context switch time period
// OS_Sleep(0) implements cooperative multitasking
void OS_Sleep(unsigned long sleepTime)
{
OS_DisableInterrupts();
threadRemover(&SleepPt, sleepTime * 2);
sleepCount++;
switched = 1;
OS_Suspend();
OS_EnableInterrupts();
}
// ******** OS_Kill ************
// kill the currently running thread, release its TCB and stack
// input: none
// output: none
void OS_Kill(void)
{
OS_DisableInterrupts();
threadRemover(&DeadPt, 0); //parameter 0 will be ignored
deadCount++;
switched = 1;
OS_Suspend();
OS_EnableInterrupts();
}
void TriggerSensor0(void) {
int i;
OS_DisableInterrupts();
GPIO_PORTB0 = 0x01;
// delay 5 us
for (i = 0; i < 75; i++);
GPIO_PORTB0 = 0x00;
GPIO_PORTB_DIR_R &= ~0x01; // make PB0 in
GPIO_PORTB_IM_R |= 0x01; // enable PB0 interrupts
OS_EnableInterrupts();
}
// ******** OS_bWait ************
// Lab2 spinlock, set to 0
// Lab3 block if less than zero
// input: pointer to a binary semaphore
// output: none
void OS_bWait(Sema4Type *semaPt)
{
int32_t status;
status = OS_StartCritical();
while((*semaPt).Value == 0)
{
OS_Block(semaPt); //block and put into semaphore blocked list
OS_Suspend();
OS_EnableInterrupts();
OS_DisableInterrupts();
} //while someone has the semaphor
(*semaPt).Value = 0; //take the semaphore
EndCritical(status );
}
// ******** OS_Wait ************
// decrement semaphore
// Lab2 spinlock
// Lab3 block if less than zero
// input: pointer to a counting semaphore
// output: none
void OS_Wait(Sema4Type *semaPt)
{
uint32_t status;
status = OS_StartCritical();
(*semaPt).Value--; //decrease count
if((*semaPt).Value < 0)
{
OS_Block(semaPt); //block and put into semaphore blocked list
OS_Suspend();
OS_EnableInterrupts();
OS_DisableInterrupts();
}
OS_EndCritical(status);
}
void Ping_Init(void) {
volatile unsigned long delay;
OS_DisableInterrupts();
SYSCTL_RCGC2_R |= SYSCTL_RCGC2_GPIOB; // activate port B
delay = SYSCTL_RCGC2_R;
// **** Port B Edge Trigger Initialization ****
GPIO_PORTB_DIR_R |= 0x03; // make PB0-1 out
GPIO_PORTB_DEN_R |= 0x03; // enable digital I/O on PB0-1
GPIO_PORTB_PUR_R |= 0x03; // enable pull up on PB0-1
GPIO_PORTB_IEV_R |= 0x03; // make PB0-1 rising edge triggered
GPIO_PORTB_IS_R &= ~0x03; // make PB0-1 edge-sensitive
GPIO_PORTB_ICR_R = 0x03; // clear flag
NVIC_PRI0_R = (NVIC_PRI1_R&0xFFFF00FF)|0x00006000; // priority 3
NVIC_EN0_R |= NVIC_EN0_INT1;
OS_InitSemaphore(&Sensor0Free, 1);
OS_InitSemaphore(&Sensor1Free, 1);
OS_InitSemaphore(&Sensor0DataAvailable, 0);
OS_InitSemaphore(&Sensor1DataAvailable, 0);
OS_EnableInterrupts();
}
