Minor logic changes

student-distrib/keyboard.c

@@ -383,8 +383,8 @@ void KB_handler(void) {
         clear();
         reset_cursor();
 
-        if(terminal[visible_terminal].pcb->shell_flag)
-            printf("391OS> ");
+        //if(terminal[visible_terminal].pcb->shell_flag)
+        //    printf("391OS> ");
 
         remap2(running_terminal);
         send_eoi(KB_IRQ);

student-distrib/paging.c

@@ -80,16 +80,15 @@ void remap2(int32_t term_id){
  * Return Value: void
  * Function: Initialises page for video memory
  */
-void remap_vidmem(){
+void remap_vidmem()
+{
     
     page_directory[33] = (uint32_t)(uint32_t)page_table | USER | READ_WRITE | PRESENT;
 
     if(visible_terminal == running_terminal)
-
         page_table[0] = ((uint32_t)0xB8000) | USER | READ_WRITE | PRESENT;
-
+        
     else
-
         page_table[0] = ((uint32_t)(0xB8000 + (running_terminal+1)*0x1000 )) | USER | READ_WRITE | PRESENT;
 
     // flush TLB

student-distrib/proc.c

@@ -12,18 +12,20 @@ int32_t fail(){
     return -1;
 }
 
+/* Initialized at bootup */
 void control_initilization(void)
 {
     int i;
+
+    /* All PID entries to present */
     for(i = 0; i < MAX_PROCESS; i++)
          pid_array[i] = 0;
 
      total_prog_count  = 0;
-     visible_terminal      = 0;
+     visible_terminal  = 0;
      running_terminal  = 0;
-     cur_pid = 0;
-     counter = 0;
-    // running_terminal = 0;
+     cur_pid           = 0;
+     counter           = 0;
 }
 
 /* Checks if FD is valid
@@ -41,7 +43,7 @@ int32_t fd_check(int32_t fd)
     return -1;
 }
 
-//clearing fd
+/* Clear FD for process on halt */
 void fd_clear(int32_t fd)
 {
      terminal[ running_terminal].pcb->fd[fd].fileop_ptr.read  = 0;
@@ -51,14 +53,18 @@ void fd_clear(int32_t fd)
      terminal[ running_terminal].pcb->fd[fd].inode_index      = 0;
      terminal[ running_terminal].pcb->fd[fd].file_pos         = 0;
      terminal[ running_terminal].pcb->fd[fd].flags            = 0;
+
     return;
 }
 
-//initialize pcb
+/* Initialize PCB for new process on execute */
 void pcb_init(pcb_t* pcb , uint8_t* parsed_cmd, uint8_t (*argv)[MAX_ARGUMENT_SIZE], uint32_t pid, uint32_t arg_num)
 {
     int i;
-    for( i = 0; i < MAX_FILE_NUM ; i++){
+
+    /* Set FD array */
+    for( i = 0; i < MAX_FILE_NUM ; i++)
+    {
         pcb->fd[i].fileop_ptr.read  = 0;
         pcb->fd[i].fileop_ptr.write = 0;
         pcb->fd[i].fileop_ptr.open  = 0;
@@ -68,31 +74,28 @@ void pcb_init(pcb_t* pcb , uint8_t* parsed_cmd, uint8_t (*argv)[MAX_ARGUMENT_SIZ
         pcb->fd[i].flags            = 0;
     }
 
-    //initialze stdin
+    /* Initialze STDIN */
     pcb->fd[STDIN_FD].fileop_ptr  = (f_table_t)stdin_jumptable;
     pcb->fd[STDIN_FD].inode_index = 0;
     pcb->fd[STDIN_FD].file_pos    = 0;
     pcb->fd[STDIN_FD].flags       = 1;
 
-    //initialze stdout
+    /* Initialize STDOUT */
     pcb->fd[STDOUT_FD].fileop_ptr  = (f_table_t)stdout_jumptable;
     pcb->fd[STDOUT_FD].inode_index = 0;
     pcb->fd[STDOUT_FD].file_pos    = 0;
     pcb->fd[STDOUT_FD].flags       = 1;
 
-
+    /* Set the PID sent in as argument */
     pcb->pid = pid;
 
     pcb->scheduler_flag = 0;
 
-    // no program other than the shell initiates another program
+    /* no program other than the shell initiates another program */
     pcb->parent_pid = 0;
 
     pcb->arg_num = arg_num;
 
-    pcb->running_terminal =  visible_terminal;
-    pcb->shell_flag = 0;
-
     memcpy(pcb->cmd, parsed_cmd, MAX_COMMAND_SIZE);
 
     for(i = 0; i < MAX_ARGUMENT_NUM; i++)
@@ -100,26 +103,14 @@ void pcb_init(pcb_t* pcb , uint8_t* parsed_cmd, uint8_t (*argv)[MAX_ARGUMENT_SIZ
 
     pcb->parent_esp  = 0;
     pcb->parent_ebp  = 0;
-    pcb->parent_pcb  =  terminal[visible_terminal].pcb;
-    pcb->tss_esp0 =  tss.esp0;
+    pcb->parent_pcb  =  terminal[running_terminal].pcb;
+    pcb->tss_esp0    =  tss.esp0;
 
     return;
 }
 
-//function that return a pointer to the current pcb
-pcb_t* current_pcb(void)
-{
-    pcb_t* pcb;
-    asm volatile(
-         "andl %%esp, %0"
-         : "=r" (pcb)
-         : "r" (PCB_M)
-         );
-    return pcb;
-}
-
-//parsing the command, extract command and argument
-//return number of arguments when success, -2 when exit, -1 when fail
+/* Parsing the command, extracting the command and the argument
+ * returns number of arguments when successful, -2 fot exit, -1 for failure */
 int32_t parse_cmd(const uint8_t* command, uint8_t* parsed_cmd, uint8_t (*argv)[MAX_ARGUMENT_SIZE])
 {
     int32_t i,j, command_length;

student-distrib/rtc.c

@@ -84,7 +84,7 @@ int32_t rtc_read(int32_t fd, void* buf, int32_t nbytes)
     /* Set flag */
     rtc_flag[running_terminal] = 1;
 
-    //interrupt_flag = 1;
+    
     sti();
 
     /* Wait until interrupt handler clears flag */

student-distrib/syscall.c

@@ -35,7 +35,7 @@ int32_t halt (uint8_t status)
     {
         clear_pid(pcb_cur->pid);
         total_prog_count--;
-        terminal[pcb_cur->running_terminal].terminal_prog_count--;
+        terminal[running_terminal].terminal_prog_count--;
     }
 
     if(terminal[running_terminal].terminal_prog_count == 0)
@@ -212,13 +212,6 @@ int32_t execute(const uint8_t* command)
 
         terminal[running_terminal].pcb = pcb_ptr;
 
-        if(strncmp("shell", (int8_t *) parsed_cmd, 5) == 0)
-            terminal[running_terminal].pcb->shell_flag = 1;
-
-        //printf("[EXE] using pcb = %x\n", terminal[running_terminal].pcb);
-
-        //printf("[EXE] set pcb ebp to %x , esp to %x\n", terminal[running_terminal].pcb->current_ebp, terminal[running_terminal].pcb->current_esp);
-        //printf("[EXE] should be ebp %x , esp %x\n", temp_ebp, temp_esp);
     //--------------------- 6: scheduling initilization -----------------------
 
 

student-distrib/types.h

@@ -143,9 +143,6 @@ typedef struct pcb {
 
     file_object_t   fd[MAX_FILE_NUM]; /* File descriptor array */
 
-    int32_t         running_terminal;
-    int32_t         shell_flag;
-
     int32_t         scheduler_flag;
 
     uint32_t        pid;              /* Holds current process ID */