working text mode

cvideo.h

@@ -10,6 +10,12 @@
 #define WORDS_PER_LINE   (VIDEO_WIDTH / 32)
 #define LINES_PER_FIELD  (VIDEO_HEIGHT / 2)
 
+// Active and visible field in the framebuffer
+#define START_X 35
+#define END_X (VIDEO_WIDTH-40)
+#define START_Y 20
+#define END_Y (VIDEO_HEIGHT-40)
+
 typedef uint32_t video_framebuffer_t[VIDEO_HEIGHT][WORDS_PER_LINE];
 typedef uint32_t (*video_framebuffer_ptr_t)[WORDS_PER_LINE];