Merge branch 'lab4' into lab5

kern/monitor.c

@@ -22,6 +22,7 @@ struct Command {
 	int (*func)(int argc, char** argv, struct Trapframe* tf);
 };
 
+// LAB 1: add your command to here...
 static struct Command commands[] = {
 	{ "help", "Display this list of commands", mon_help },
 	{ "kerninfo", "Display information about the kernel", mon_kerninfo },
@@ -58,7 +59,9 @@ mon_kerninfo(int argc, char **argv, struct Trapframe *tf)
 int
 mon_backtrace(int argc, char **argv, struct Trapframe *tf)
 {
-	// Your code here.
+	// LAB 1: Your code here.
+    // HINT 1: use read_ebp().
+    // HINT 2: print the current ebp on the first line (not current_ebp[0])
 	return 0;
 }
 

kern/sched.c

@@ -75,6 +75,7 @@ sched_halt(void)
 		"movl %0, %%esp\n"
 		"pushl $0\n"
 		"pushl $0\n"
+        // LAB 4:
 		// Uncomment the following line after completing exercise 13
 		//"sti\n"
 		"1:\n"

kern/trap.c

@@ -66,14 +66,26 @@ static const char *trapname(int trapno)
 }
 
 
+// XYZ: write a function declaration here...
+// e.g., void t_divide();
+
 void
 trap_init(void)
 {
 	extern struct Segdesc gdt[];
 
+    /*
+     *
+     * HINT
+     * Do something like this: SETGATE(idt[T_DIVIDE], 0, GD_KT, t_divide, 0);
+     * if your trap handler's name for divide by zero is t_device.
+     * Additionally, you should declare trap handler as a function
+     * to refer that in C code... (see the comment XYZ above)
+     *
+     */
 	// LAB 3: Your code here.
 
-	// Per-CPU setup 
+	// Per-CPU setup
 	trap_init_percpu();
 }
 

kern/trapentry.S

@@ -48,9 +48,15 @@
  * Lab 3: Your code here for generating entry points for the different traps.
  */
 
-
+// HINT 1 : TRAPHANDLER_NOEC(t_divide, T_DIVIDE);
+//          Do something like this if there is no error code for the trap
+// HINT 2 : TRAPHANDLER(t_dblflt, T_DBLFLT);
+//          Do something like this if the trap includes an error code..
+// HINT 3 : READ Intel's manual to check if the trap includes an error code
+//          or not...
 
 /*
  * Lab 3: Your code here for _alltraps
  */
 
+