From ba2b4e15a9d3a67f9730c4f24a432b774239c12e Mon Sep 17 00:00:00 2001
From: h2-addad <hamza2.addad@live.uwe.ac.uk>
Date: Sun, 16 Jul 2023 00:39:33 +0000
Subject: [PATCH] Upload New File
---
src/devices/vga.c | 172 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 172 insertions(+)
create mode 100644 src/devices/vga.c
diff --git a/src/devices/vga.c b/src/devices/vga.c
new file mode 100644
index 0000000..f421b61
--- /dev/null
+++ b/src/devices/vga.c
@@ -0,0 +1,172 @@
+#include "devices/vga.h"
+#include <round.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <string.h>
+#include "devices/speaker.h"
+#include "threads/io.h"
+#include "threads/interrupt.h"
+#include "threads/vaddr.h"
+
+/* VGA text screen support. See [FREEVGA] for more information. */
+
+/* Number of columns and rows on the text display. */
+#define COL_CNT 80
+#define ROW_CNT 25
+
+/* Current cursor position. (0,0) is in the upper left corner of
+ the display. */
+static size_t cx, cy;
+
+/* Attribute value for gray text on a black background. */
+#define GRAY_ON_BLACK 0x07
+
+/* Framebuffer. See [FREEVGA] under "VGA Text Mode Operation".
+ The character at (x,y) is fb[y][x][0].
+ The attribute at (x,y) is fb[y][x][1]. */
+static uint8_t (*fb)[COL_CNT][2];
+
+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. */
+static void
+init (void)
+{
+ /* 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. */
+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':
+ newline ();
+ break;
+
+ case '\f':
+ cls ();
+ break;
+
+ case '\b':
+ if (cx > 0)
+ cx--;
+ break;
+
+ case '\r':
+ cx = 0;
+ break;
+
+ case '\t':
+ cx = ROUND_UP (cx + 1, 8);
+ if (cx >= COL_CNT)
+ newline ();
+ break;
+
+ case '\a':
+ intr_set_level (old_level);
+ speaker_beep ();
+ intr_disable ();
+ break;
+
+ default:
+ fb[cy][cx][0] = c;
+ fb[cy][cx][1] = GRAY_ON_BLACK;
+ if (++cx >= COL_CNT)
+ newline ();
+ break;
+ }
+
+ /* Update cursor position. */
+ move_cursor ();
+
+ intr_set_level (old_level);
+}
+
+/* Clears the screen and moves the cursor to the upper left. */
+static void
+cls (void)
+{
+ size_t y;
+
+ for (y = 0; y < ROW_CNT; y++)
+ clear_row (y);
+
+ cx = cy = 0;
+ move_cursor ();
+}
+
+/* Clears row Y to spaces. */
+static void
+clear_row (size_t y)
+{
+ size_t x;
+
+ for (x = 0; x < COL_CNT; x++)
+ {
+ fb[y][x][0] = ' ';
+ fb[y][x][1] = GRAY_ON_BLACK;
+ }
+}
+
+/* Advances the cursor to the first column in the next line on
+ the screen. If the cursor is already on the last line on the
+ screen, scrolls the screen upward one line. */
+static void
+newline (void)
+{
+ cx = 0;
+ cy++;
+ if (cy >= ROW_CNT)
+ {
+ cy = ROW_CNT - 1;
+ memmove (&fb[0], &fb[1], sizeof fb[0] * (ROW_CNT - 1));
+ clear_row (ROW_CNT - 1);
+ }
+}
+
+/* Moves the hardware cursor to (cx,cy). */
+static void
+move_cursor (void)
+{
+ /* See [FREEVGA] under "Manipulating the Text-mode Cursor". */
+ uint16_t cp = cx + COL_CNT * cy;
+ outw (0x3d4, 0x0e | (cp & 0xff00));
+ 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;
+}
--
GitLab