before testing 3.2

proc.c

@@ -324,6 +324,7 @@ scheduler(void)
 {
   struct proc *p;
   struct cpu *c = mycpu();
+  struct proc *p1;
   c->proc = 0;
   
   for(;;){
@@ -336,6 +337,23 @@ scheduler(void)
       if(p->state != RUNNABLE)
         continue;
 
+      //choose highest priority 
+      struct proc* minimum = ptable.proc ;
+      for(p1 = ptable.proc ; p1 <&ptable.proc[NPROC];p1++){
+        if(p1->state != RUNNABLE){
+          continue;
+        }
+        if(minimum->calculatedPriority > (p1->calculatedPriority)){
+          minimum = p1; 
+        }
+      }
+      minimum-> calculatedPriority += minimum ->priority;
+      
+      //for controling larg int and destroy negative priority
+      if(minimum->calculatedPriority<0){
+        minimum->calculatedPriority = 0;
+      }
+      p = minimum;
       // Switch to chosen process.  It is the process's job
       // to release ptable.lock and then reacquire it
       // before jumping back to us.

proc.h

@@ -39,6 +39,7 @@ struct proc {
   int usagepointer;
   int usage[100];
   int priority;
+  int calculatedPriority;
   uint sz;                     // Size of process memory (bytes)
   pde_t* pgdir;                // Page table
   char *kstack;                // Bottom of kernel stack for this process

syscall.c

@@ -105,6 +105,7 @@ extern int sys_write(void);
 extern int sys_uptime(void);
 extern int sys_getChildren(void);
 extern int sys_getCount(void);
+extern int sys_changePriority(void);
 
 static int (*syscalls[])(void) = {
 [SYS_fork]    sys_fork,
@@ -129,7 +130,8 @@ static int (*syscalls[])(void) = {
 [SYS_mkdir]   sys_mkdir,
 [SYS_close]   sys_close,
 [SYS_getChildren]   sys_getChildren,
-[SYS_getCount] sys_getCount
+[SYS_getCount]  sys_getCount,
+[SYS_changePriority]  sys_changePriority  
 };
 
 void

syscall.h

@@ -22,3 +22,4 @@
 #define SYS_close  21
 #define SYS_getChildren  22
 #define SYS_getCount  23
+#define SYS_changePriority  24

sysproc.c

@@ -138,6 +138,20 @@ sys_getCount(int find){
   return counter;
 }
 
+//3.2
+int
+changePriority(int newPriority){
+  argint(0,&newPriority);
+  if(newPriority > 5 || newPriority < 0){
+    return -1;
+  }
+  myproc()->calculatedPriority = newPriority;
+  myproc()->priority = newPriority ;
+
+
+  return 5;
+}
+
 
 
 

user.h

@@ -25,6 +25,7 @@ int sleep(int);
 int uptime(void);
 int getChildren(int);
 int getCount(int);
+int changePriority(int);
 
 // ulib.c
 int stat(const char*, struct stat*);

usys.S

@@ -31,3 +31,4 @@ SYSCALL(sleep)
 SYSCALL(uptime)
 SYSCALL(getChildren)
 SYSCALL(getCount)
+SYSCALL(changePriority)