From 326526206eface026e6ec291d75cd037dbec6609 Mon Sep 17 00:00:00 2001
From: James Barnett <noreply@jamesbarnett.xyz>
Date: Tue, 28 Aug 2018 18:02:17 +0100
Subject: Add text colour manipulation

---
 kernel/io/text_mode_diplay.h      |  3 ---
 kernel/io/text_mode_display.c     | 34 -------------------------------
 kernel/io/vga/colours.h           | 16 +++++++++++++++
 kernel/io/vga/text_mode_diplay.h  |  4 ++++
 kernel/io/vga/text_mode_display.c | 42 +++++++++++++++++++++++++++++++++++++++
 kernel/kernel.c                   | 12 +++++++++--
 6 files changed, 72 insertions(+), 39 deletions(-)
 delete mode 100644 kernel/io/text_mode_diplay.h
 delete mode 100644 kernel/io/text_mode_display.c
 create mode 100644 kernel/io/vga/colours.h
 create mode 100644 kernel/io/vga/text_mode_diplay.h
 create mode 100644 kernel/io/vga/text_mode_display.c

(limited to 'kernel')

diff --git a/kernel/io/text_mode_diplay.h b/kernel/io/text_mode_diplay.h
deleted file mode 100644
index d2d1180..0000000
--- a/kernel/io/text_mode_diplay.h
+++ /dev/null
@@ -1,3 +0,0 @@
-void clear_screen();
-void print(char *msg);
-void print_ln(char *msg);
\ No newline at end of file
diff --git a/kernel/io/text_mode_display.c b/kernel/io/text_mode_display.c
deleted file mode 100644
index 514ba9f..0000000
--- a/kernel/io/text_mode_display.c
+++ /dev/null
@@ -1,34 +0,0 @@
-#define COLS 80
-#define ROWS 25
-#define FRAME_SIZE (ROWS * COLS * 2) // 2 bytes per char
-
-char *video_ram = (char *)0xB8000;
-int cursor_pos = 0;
-
-void clear_screen()
-{
-  for (int i = 0; i < FRAME_SIZE; i = i + 2)
-  {
-    video_ram[i] = ' ';
-    video_ram[i + 1] = 0x07;
-  };
-  cursor_pos = 0;
-}
-
-void print(char *msg)
-{
-  int j = 0;
-  while (msg[j] != '\0')
-  {
-    video_ram[cursor_pos++] = msg[j];
-    video_ram[cursor_pos++] = 0x07;
-    ++j;
-  }
-}
-
-void print_ln(char *msg)
-{
-  print(msg);
-  int current_line = cursor_pos / COLS;
-  cursor_pos = (current_line + 1) * (COLS*2);
-}
diff --git a/kernel/io/vga/colours.h b/kernel/io/vga/colours.h
new file mode 100644
index 0000000..a019fd3
--- /dev/null
+++ b/kernel/io/vga/colours.h
@@ -0,0 +1,16 @@
+#define COLOUR_BLACK 0x00
+#define COLOUR_BLUE 0x01
+#define COLOUR_GREEN 0x02
+#define COLOUR_CYAN 0x03
+#define COLOUR_RED 0x04
+#define COLOUR_PURPLE 0x05
+#define COLOUR_BROWN 0x06
+#define COLOUR_GRAY 0x07
+#define COLOUR_DARK_GREY 0x08
+#define COLOUR_LIGHT_BLUE 0x09
+#define COLOUR_LIGHT_GREEN 0x0A
+#define COLOUR_LIGHT_CYAN 0x0B
+#define COLOUR_LIGHT_RED 0x0C
+#define COLOUR_LIGHT_PURPLE 0x0D
+#define COLOUR_YELLOW 0x0E
+#define COLOUR_WHITE 0x0F
\ No newline at end of file
diff --git a/kernel/io/vga/text_mode_diplay.h b/kernel/io/vga/text_mode_diplay.h
new file mode 100644
index 0000000..269a6ce
--- /dev/null
+++ b/kernel/io/vga/text_mode_diplay.h
@@ -0,0 +1,4 @@
+void clear_screen();
+void print(char *msg);
+void print_ln(char *msg);
+void set_text_colour(int foreground, int background);
\ No newline at end of file
diff --git a/kernel/io/vga/text_mode_display.c b/kernel/io/vga/text_mode_display.c
new file mode 100644
index 0000000..958eb87
--- /dev/null
+++ b/kernel/io/vga/text_mode_display.c
@@ -0,0 +1,42 @@
+#include "colours.h"
+
+#define COLS (80 * 2) // 2 bytes per char
+#define ROWS 25
+#define FRAME_SIZE (ROWS * COLS)
+
+char *video_ram = (char *)0xB8000;
+int cursor_pos = 0;
+int char_attribute_byte = 0x07;
+
+void clear_screen()
+{
+  for (int i = 0; i < FRAME_SIZE; i = i + 2)
+  {
+    video_ram[i] = ' ';
+    video_ram[i + 1] = char_attribute_byte;
+  };
+  cursor_pos = 0;
+}
+
+void print(char *msg)
+{
+  int j = 0;
+  while (msg[j] != '\0')
+  {
+    video_ram[cursor_pos++] = msg[j];
+    video_ram[cursor_pos++] = char_attribute_byte;
+    ++j;
+  }
+}
+
+void print_ln(char *msg)
+{
+  print(msg);
+  int current_line = cursor_pos / COLS;
+  cursor_pos = (current_line + 1) * COLS;
+}
+
+void set_text_colour(int foreground, int background) 
+{
+  char_attribute_byte = (background << 4) | foreground;
+}
\ No newline at end of file
diff --git a/kernel/kernel.c b/kernel/kernel.c
index e872fa5..d10060a 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -1,12 +1,20 @@
-#include "./io/text_mode_diplay.h"
+#include "./io/vga/text_mode_diplay.h"
+#include "./io/vga/colours.h"
 
 void run_kern()
 {
   clear_screen();
 
   print_ln("I am a kernel!");
+  set_text_colour(COLOUR_WHITE, COLOUR_GREEN);
   print("I am on a new line");
-  print(" - I am not");
+  print_ln(" - I am not");
+
+  set_text_colour(COLOUR_RED, COLOUR_WHITE);
+  print_ln("red on white");
+
+  set_text_colour(COLOUR_WHITE, COLOUR_BLUE);
+  print_ln("white on blue");
 }
 
 void kernel_entrypoint()
-- 
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