Reorganise files

1 files changed, 64 insertions, 0 deletions

diff --git a/kernel/gpu/text_mode/display.c b/kernel/gpu/text_mode/display.c
new file mode 100644
index 0000000..3659e60
--- /dev/null
+++ b/kernel/gpu/text_mode/display.c
@@ -0,0 +1,64 @@
+#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 scrn_clear()
+{
+  for (int i = 0; i < FRAME_SIZE; i = i + 2)
+  {
+    video_ram[i] = ' ';
+    video_ram[i + 1] = char_attribute_byte;
+  };
+  cursor_pos = 0;
+}
+
+void scrn_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 scrn_println(char *msg)
+{
+  scrn_print(msg);
+  int current_line = cursor_pos / COLS;
+  cursor_pos = (current_line + 1) * COLS;
+}
+
+void scrn_set_text_colour(int foreground, int background) 
+{
+  char_attribute_byte = (background << 4) | foreground;
+}
+
+void scrn_putchar(unsigned char byte)
+{
+  video_ram[cursor_pos++] = byte;
+  video_ram[cursor_pos++] = char_attribute_byte;
+}
+
+// TODO - jump cursor to prev non 0 text char rather than reversing through whole array
+void scrn_backspace()
+{
+  if (cursor_pos != 0) 
+  {
+    video_ram[--cursor_pos] = char_attribute_byte;
+    video_ram[--cursor_pos] = 0;
+  }
+}
+
+void scrn_newline()
+{
+  int current_line = cursor_pos / COLS;
+  cursor_pos = (current_line + 1) * COLS;
+}
\ No newline at end of file