X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdevices%2Fvga.c;h=8255747244e641d599d686fadecb167a9fc6b4f7;hb=53a7f5d0952a4595f252247f5ee3d017468eb57e;hp=fdddd91de7b94e062869d416472b373f0a939e8b;hpb=7180597203a54c08582b1bb092dc465ec1d26d7c;p=pintos-anon

diff --git a/src/devices/vga.c b/src/devices/vga.c
index fdddd91..8255747 100644
--- a/src/devices/vga.c
+++ b/src/devices/vga.c
@@ -1,9 +1,11 @@
-#include "vga.h"
+#include "devices/vga.h"
+#include <round.h>
 #include <stdint.h>
 #include <stddef.h>
-#include "io.h"
-#include "lib.h"
-#include "mmu.h"
+#include <string.h>
+#include "threads/io.h"
+#include "threads/interrupt.h"
+#include "threads/vaddr.h"
 
 /* VGA text screen support.  See [FREEVGA] for more information. */
 
@@ -27,20 +29,33 @@ static void clear_row (size_t y);
 static void cls (void);
 static void newline (void);
 static void move_cursor (void);
+static void find_cursor (size_t *x, size_t *y);
 
-/* Initializes the VGA text display and clears the screen. */
-void
-vga_init (void)
+/* Initializes the VGA text display. */
+static void
+init (void)
 {
-  fb = ptov (0xb8000);
-  cls ();
+  /* Already initialized? */
+  static bool inited;
+  if (!inited)
+    {
+      fb = ptov (0xb8000);
+      find_cursor (&cx, &cy);
+      inited = true; 
+    }
 }
 
 /* Writes C to the VGA text display, interpreting control
-   characters in the conventional ways. */
+   characters in the conventional ways.  */
 void
 vga_putc (int c)
 {
+  /* Disable interrupts to lock out interrupt handlers
+     that might write to the console. */
+  enum intr_level old_level = intr_disable ();
+
+  init ();
+  
   switch (c) 
     {
     case '\n':
@@ -76,6 +91,8 @@ vga_putc (int c)
 
   /* Update cursor position. */
   move_cursor ();
+
+  intr_set_level (old_level);
 }
 
 /* Clears the screen and moves the cursor to the upper left. */
@@ -130,3 +147,19 @@ move_cursor (void)
   outw (0x3d4, 0x0f | (cp << 8));
 }
 
+/* Reads the current hardware cursor position into (*X,*Y). */
+static void
+find_cursor (size_t *x, size_t *y) 
+{
+  /* See [FREEVGA] under "Manipulating the Text-mode Cursor". */
+  uint16_t cp;
+
+  outb (0x3d4, 0x0e);
+  cp = inb (0x3d5) << 8;
+
+  outb (0x3d4, 0x0f);
+  cp |= inb (0x3d5);
+
+  *x = cp % COL_CNT;
+  *y = cp / COL_CNT;
+}