Upload New File

Labware/Lab2_4C123/os.h

+// os.h
+// Runs on LM4F120/TM4C123/MSP432
+// A very simple real time operating system with minimal features.
+// Daniel Valvano
+// February 20, 2016
+
+/* This example accompanies the book
+
+   "Embedded Systems: Real-Time Operating Systems for ARM Cortex-M Microcontrollers",
+   ISBN: 978-1466468863, , Jonathan Valvano, copyright (c) 2016
+   Programs 4.4 through 4.12, section 4.2
+
+ Copyright 2016 by Jonathan W. Valvano, valvano@mail.utexas.edu
+    You may use, edit, run or distribute this file
+    as long as the above copyright notice remains
+ THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
+ OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
+ MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
+ VALVANO SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL,
+ OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
+ For more information about my classes, my research, and my books, see
+ http://users.ece.utexas.edu/~valvano/
+ */
+
+
+#ifndef __OS_H
+#define __OS_H  1
+// grader needs access to TCBs and stacks
+#define NUMTHREADS  4        // maximum number of threads
+#define STACKSIZE   100      // number of 32-bit words in stack per thread
+struct tcb{
+  int32_t *sp;       // pointer to stack (valid for threads not running
+  struct tcb *next;  // linked-list pointer
+};
+typedef struct tcb tcbType;
+
+// ******** OS_Init ************
+// Initialize operating system, disable interrupts
+// Initialize OS controlled I/O: systick, bus clock as fast as possible
+// Initialize OS global variables
+// Inputs:  none
+// Outputs: none
+void OS_Init(void);
+
+
+
+//******** OS_AddThreads ***************
+// Add four main threads to the scheduler
+// Inputs: function pointers to four void/void main threads
+// Outputs: 1 if successful, 0 if this thread can not be added
+// This function will only be called once, after OS_Init and before OS_Launch
+int OS_AddThreads(void(*thread0)(void),
+                  void(*thread1)(void),
+                  void(*thread2)(void),
+                  void(*thread3)(void));
+
+//******** OS_AddThreads3 ***************
+// add three foregound threads to the scheduler 
+// This is needed during debugging and not part of final solution
+// Inputs: three pointers to a void/void foreground tasks
+// Outputs: 1 if successful, 0 if this thread can not be added
+int OS_AddThreads3(void(*task0)(void),
+                 void(*task1)(void),
+                 void(*task2)(void));
+                 
+//******** OS_AddPeriodicEventThreads ***************
+// Add two background periodic event threads
+// Typically this function receives the highest priority
+// Inputs: pointers to a void/void event thread function2
+//         periods given in units of OS_Launch (Lab 2 this will be msec)
+// Outputs: 1 if successful, 0 if this thread cannot be added
+// It is assumed that the event threads will run to completion and return
+// It is assumed the time to run these event threads is short compared to 1 msec
+// These threads cannot spin, block, loop, sleep, or kill
+// These threads can call OS_Signal
+int OS_AddPeriodicEventThreads(void(*thread1)(void), uint32_t period1,
+  void(*thread2)(void), uint32_t period2);
+
+//******** OS_Launch ***************
+// Start the scheduler, enable interrupts
+// Inputs: number of clock cycles for each time slice
+// Outputs: none (does not return)
+// Errors: theTimeSlice must be less than 16,777,216
+void OS_Launch(uint32_t theTimeSlice);
+
+
+// ******** OS_InitSemaphore ************
+// Initialize counting semaphore
+// Inputs:  pointer to a semaphore
+//          initial value of semaphore
+// Outputs: none
+void OS_InitSemaphore(int32_t *semaPt, int32_t value);
+
+// ******** OS_Wait ************
+// Decrement semaphore
+// Lab2 spinlock (does not suspend while spinning)
+// Lab3 block if less than zero
+// Inputs:  pointer to a counting semaphore
+// Outputs: none
+void OS_Wait(int32_t *semaPt);
+
+// ******** OS_Signal ************
+// Increment semaphore
+// Lab2 spinlock
+// Lab3 wakeup blocked thread if appropriate
+// Inputs:  pointer to a counting semaphore
+// Outputs: none
+void OS_Signal(int32_t *semaPt);
+
+// ******** OS_MailBox_Init ************
+// Initialize communication channel
+// Producer is an event thread, consumer is a main thread
+// Inputs:  none
+// Outputs: none
+void OS_MailBox_Init(void);
+
+// ******** OS_MailBox_Send ************
+// Enter data into the MailBox, do not spin/block if full
+// Use semaphore to synchronize with OS_MailBox_Recv
+// Inputs:  data to be sent
+// Outputs: none
+// Errors: data lost if MailBox already has data
+void OS_MailBox_Send(uint32_t data);
+
+// ******** OS_MailBox_Recv ************
+// retreive mail from the MailBox
+// Use semaphore to synchronize with OS_MailBox_Send
+// Lab 2 spin on semaphore if mailbox empty
+// Lab 3 block on semaphore if mailbox empty
+// Inputs:  none
+// Outputs: data retreived
+// Errors:  none
+uint32_t OS_MailBox_Recv(void);
+
+#endif