Add text colour manipulation

6 files changed, 46 insertions, 13 deletions

diff --git a/build.sh b/build.sh
index 9b67fcb..6de1500 100755
--- a/build.sh
+++ b/build.sh
@@ -3,9 +3,9 @@
 # TODO - proper makefile
 
 rm -rf bin/kernel/*
-mkdir -p bin/kernel/io
+mkdir -p bin/kernel/io/vga
 nasm -f elf32 kernel/kernel-bootstrap.asm -o bin/kernel-bootstrap.o
 gcc -m32 -std=c99 -c kernel/kernel.c -o bin/kernel/kernel.o
-gcc -m32 -std=c99 -c kernel/io/text_mode_display.c -o bin/kernel/io/text_mode_display.o
-ld -m elf_i386 -T link.ld -o bin/kern bin/kernel-bootstrap.o bin/kernel/kernel.o bin/kernel/io/text_mode_display.o
+gcc -m32 -std=c99 -c kernel/io/vga/text_mode_display.c -o bin/kernel/io/vga/text_mode_display.o
+ld -m elf_i386 -T link.ld -o bin/kern bin/kernel-bootstrap.o bin/kernel/kernel.o bin/kernel/io/vga/text_mode_display.o
 #ld -m elf_i386 -T link.ld -o bin/kern bin/kernel-bootstrap.o bin/**/*.o
\ No newline at end of file
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/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/text_mode_display.c b/kernel/io/vga/text_mode_display.c
index 514ba9f..958eb87 100644
--- a/kernel/io/text_mode_display.c
+++ b/kernel/io/vga/text_mode_display.c
@@ -1,16 +1,19 @@
-#define COLS 80
+#include "colours.h"
+
+#define COLS (80 * 2) // 2 bytes per char
 #define ROWS 25
-#define FRAME_SIZE (ROWS * COLS * 2) // 2 bytes per char
+#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] = 0x07;
+    video_ram[i + 1] = char_attribute_byte;
   };
   cursor_pos = 0;
 }
@@ -21,7 +24,7 @@ void print(char *msg)
   while (msg[j] != '\0')
   {
     video_ram[cursor_pos++] = msg[j];
-    video_ram[cursor_pos++] = 0x07;
+    video_ram[cursor_pos++] = char_attribute_byte;
     ++j;
   }
 }
@@ -30,5 +33,10 @@ void print_ln(char *msg)
 {
   print(msg);
   int current_line = cursor_pos / COLS;
-  cursor_pos = (current_line + 1) * (COLS*2);
+  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()