[#57] Fix typo and append conding convention

src/threads/thread.c

@@ -12,7 +12,6 @@
 #include "threads/synch.h"
 #include "threads/vaddr.h"
 #ifdef USERPROG
-#include "threads/malloc.h"
 #include "userprog/process.h"
 #endif
 
@@ -191,6 +190,7 @@ thread_create (const char *name, int priority,
   struct process *curr_proc = process_current ();
   struct process *new_proc = &t->process;
 
+  /* Initialize process. */
   new_proc->pid = t->tid;
   new_proc->parent = curr_proc;
   new_proc->status = PROCESS_LOADING;

src/userprog/exception.c

@@ -155,7 +155,7 @@ page_fault (struct intr_frame *f)
   if (!user)
     {
       f->eip = (void (*) (void)) f->eax;
-      f->eax = (uint32_t) 0xffffffff;
+      f->eax = (uint32_t) -1;
       return;
     }
 

src/userprog/process.c

@@ -53,7 +53,7 @@ process_execute (const char *file_name)
   args = (struct arguments *) malloc (sizeof (struct arguments));
   argument_parser (fn_copy, args); 
 
-  /* Create a new thread to execute FILE_NAME. */
+  /* Create a new thread to execute the given file name. */
   pid = (pid_t) thread_create (args->argv[0], PRI_DEFAULT, start_process, args);
   if (pid == TID_ERROR)
     {
@@ -64,8 +64,9 @@ process_execute (const char *file_name)
   return pid;
 }
 
-/* Parse arguments from given string, which removes whole adjacent spaces and replace it  
-   with a null character. And then stores it in given argument struct by pointer. */
+/* Parse arguments from the given string by replacing whole
+   adjacent spaces to the null character. Then store it in
+   given argument struct by pointer. */
 static void
 argument_parser (char *str_input, struct arguments *args)
 {
@@ -129,10 +130,7 @@ start_process (void *arguments)
    exception), returns -1.  If TID is invalid or if it was not a
    child of the calling process, or if process_wait() has already
    been successfully called for the given TID, returns -1
-   immediately, without waiting.
-
-   This function will be implemented in problem 2-2.  For now, it
-   does nothing. */
+   immediately, without waiting. */
 int
 process_wait (tid_t child_tid UNUSED) 
 {
@@ -148,7 +146,7 @@ process_wait (tid_t child_tid UNUSED)
   return child->exit_code;
 }
 
-/* Free the current process's resources. */
+/* Frees the current process's resources. */
 void
 process_exit (void)
 {
@@ -164,7 +162,7 @@ process_exit (void)
         child->parent = NULL;
     }
 
-  /* Free resources. */
+  /* Update the process status and free resources. */
   proc->status |= PROCESS_EXIT;
   list_remove (&proc->elem);
   file_close (proc->exec_file);
@@ -406,6 +404,7 @@ load (struct arguments *args, void (**eip) (void), void **esp,
   if (!setup_stack (esp))
     goto fail;
 
+  /* Push arguments on stack. */
   push_args_on_stack (args, esp);
 
   /* Start address. */

src/userprog/syscall.c

@@ -10,9 +10,7 @@
 
 #define pid_t int
 
-/* A Lock for mutual exclusion between system calls.
-   This lock must be released immediately when a thread is no longer
-   running a code which must be executed in mutually exclueded state. */
+/* A Lock for mutual exclusion between system calls. */
 static struct lock sys_lock;
 
 static int get_byte (const uint8_t *uaddr);
@@ -88,8 +86,7 @@ get_word (const uint32_t *uaddr)
   return res;
 }
 
-/* Handler which matches appropriate handler to system calls.
-   Dispatching handlers with arguments they need. */
+/* Handler which matches the appropriate system call. */
 static void
 syscall_handler (struct intr_frame *f UNUSED) 
 {
@@ -143,23 +140,31 @@ syscall_handler (struct intr_frame *f UNUSED)
       syscall_close ((int) get_word (esp + 1));
       break;
     default:
+      /* Undefined system calls. */
       thread_exit ();
     }
 }
 
-/* Terminate pintos. */
+/* Terminates pintos. */
 static void 
 syscall_halt (void)
 {
   power_off ();
   NOT_REACHED ();
 }
 
+/* Terminates the current user program, returning status
+   to the kernel. */
 void
 syscall_exit (int status)
 {
+  /* Set exit code. */
   process_current ()->exit_code = status;
+
+  /* Print the termination message. */
   printf ("%s: exit(%d)\n", thread_current ()->name, status);
+
+  /* Exit the current thread. */
   thread_exit ();
   NOT_REACHED ();
 }