# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1291945474 -7200
# Node ID 0489a34ab348d9c41f4651f2a5940027ec68a2cf
# Parent  a9176938bce1dfddeb613032d6db0884f92a9ece
- reverted the trunk back to hardware scrolling
- added a missing include (ctype.h in term.c)
- added  a comment explaining what memset16 does
- beefed up the README file

diff -r a9176938bce1 -r 0489a34ab348 README
--- a/README	Sat Dec 04 10:12:39 2010 +0200
+++ b/README	Fri Dec 10 03:44:34 2010 +0200
@@ -1,3 +1,43 @@
-Code for article 1
+Article 1 source code
+---------------------
 Author: John Tsiombikas <nuclear@member.fsf.org>
-License: GNU GPL v3 (or later).
+
+License: GNU GPL v3 or any later version published by the free software
+    foundation. See COPYING for details.
+
+About
+-----
+This is the supplemental source code for the first part of the introduction to
+kernel development articles. It deals with booting up from a multiboot-compliant
+boot loader and using the VGA for text output.
+
+Compiling & Running
+-------------------
+To compile kernel image (kernel.elf) just type make (or gmake, if your default
+make tool is not GNU make). A script called "run" is supplied that will use qemu
+to run the kernel in a virtual machine.
+
+If you wish to boot up the kernel on your computer you need a multiboot
+compliant boot loader like GRUB. Since you probably already have GRUB installed
+if you're running a GNU/Linux distribution, just add an entry to the GRUB config
+file (commonly /boot/grub/menu.lst) similar to this one and reboot:
+
+title My kernel
+root (hdX,Y)  # where X is the disk number and Y the partition (first being 0)
+kernel /path/to/kernel_code/kernel.elf    # change this to the actual path
+
+In case you are using GRUB 2 instead of the original GRUB, you'll have to
+consult the documentation on how to modify the above into the GRUB 2 syntax.
+
+Disclaimer
+----------
+All programs contain bugs, and this sample code will undoubtedly have its share.
+Running buggy kernel code on the real machine is very dangerous and may result
+in data loss or even damage to your computer in extreme cases. The author
+assumes no responsibility for any such eventuality. Run this code on your
+computer at your own risk.
+
+Contact
+-------
+For any comments or suggestions regarding the articles or this supplemental
+code, please contact me at nuclear@member.fsf.org
diff -r a9176938bce1 -r 0489a34ab348 src/klibc/string.c
--- a/src/klibc/string.c	Sat Dec 04 10:12:39 2010 +0200
+++ b/src/klibc/string.c	Fri Dec 10 03:44:34 2010 +0200
@@ -8,6 +8,9 @@
 	}
 }
 
+/* Does the same thing as memset only with 16bit values.
+ * n in this case is the number of values, not the number of bytes.
+ */
 void memset16(void *s, int c, size_t n)
 {
 	short *ptr = s;
diff -r a9176938bce1 -r 0489a34ab348 src/term.c
--- a/src/term.c	Sat Dec 04 10:12:39 2010 +0200
+++ b/src/term.c	Fri Dec 10 03:44:34 2010 +0200
@@ -1,3 +1,4 @@
+#include <ctype.h>
 #include "term.h"
 #include "vid.h"
 
diff -r a9176938bce1 -r 0489a34ab348 src/vid.c
--- a/src/vid.c	Sat Dec 04 10:12:39 2010 +0200
+++ b/src/vid.c	Fri Dec 10 03:44:34 2010 +0200
@@ -1,5 +1,3 @@
-#if 0
-
 #include <string.h>
 #include "vid.h"
 #include "asmops.h"
@@ -82,64 +80,3 @@
 	outb(CRTC_START_HIGH, CRTC_ADDR);
 	outb((start_addr >> 8) & 0xff, CRTC_DATA);
 }
-#endif	/* 0 */
-
-#include <string.h>
-#include "vid.h"
-#include "asmops.h"
-
-#define WIDTH 80
-#define HEIGHT 25
-
-/* CRTC ports */
-#define CRTC_ADDR   0x3d4
-#define CRTC_DATA   0x3d5
-
-/* CRTC registers */
-#define CRTC_CURSOR_HIGH 0xe
-#define CRTC_CURSOR_LOW  0xf
-
-/* construct a character with its attributes */
-#define VMEM_CHAR(c, fg, bg) \
-    ((uint16_t)(c) | (((uint16_t)(fg) & 0xf) << 8) | \
-     (((uint16_t)(bg) & 0xf) << 12))
-
-#define CLEAR_CHAR	VMEM_CHAR(' ', LTGRAY, BLACK)
-
-/* pointer to the text mode video memory */
-static uint16_t *vmem = (uint16_t*)0xb8000;
-
-void clear_scr(void)
-{
-    memset16(vmem, CLEAR_CHAR, WIDTH * HEIGHT);
-}
-
-void set_char(char c, int x, int y, int fg, int bg)
-{
-    vmem[y * WIDTH + x] = VMEM_CHAR(c, fg, bg);
-}
-
-void set_cursor(int x, int y)
-{
-	int loc;
-    if(x < 0 || x >= WIDTH || y < 0 || y >= HEIGHT) {
-        loc = 0xffff;
-    } else {
-        loc = y * WIDTH + x;
-    }
-
-    /* tell the vga where we want the cursor by writing
-     * to the "cursor address" register of the CRTC */
-    outb(CRTC_CURSOR_LOW, CRTC_ADDR);
-    outb(loc, CRTC_DATA);
-    outb(CRTC_CURSOR_HIGH, CRTC_ADDR);
-    outb(loc >> 8, CRTC_DATA);
-}
-
-void scroll_scr(void)
-{
-    /* simple scrolling by manually copying memory */
-    memmove(vmem, vmem + WIDTH, WIDTH * (HEIGHT - 1) * 2);
-    memset16(vmem + WIDTH * (HEIGHT - 1), CLEAR_CHAR, WIDTH);
-}
-