use enum

arch/cga.h

@@ -18,6 +18,15 @@ namespace CGA {
 constexpr unsigned ROWS = 25;     ///< Visible rows in text mode
 constexpr unsigned COLUMNS = 80;  ///< Visible columns in text mode
 
+enum RegisterIndex {
+  CURSOR_START = 10,
+  CURSOR_END = 11,
+  START_ADDRESS_HIGH = 12,
+  START_ADDRESS_LOW = 13,
+  CURSOR_HIGH = 14,
+  CURSOR_LOW = 15
+};
+
 /*! \brief CGA color palette
  *
  * Colors for the attribute byte.
@@ -62,7 +71,9 @@ enum Color {
  */
 union Attribute {
   struct {
-    uint8_t todo : 8;
+    uint8_t foreground : 4;
+    uint8_t background : 3;
+    uint8_t blink : 1;
   } __attribute__((packed));
   uint8_t value;  ///< combined value
 
@@ -75,11 +86,7 @@ union Attribute {
    *  \param blink Blink if `true` (default: no blinking)
    */
   explicit Attribute(Color foreground = LIGHT_GREY, Color background = BLACK,
-                     bool blink = false) {  // NOLINT
-    (void)foreground;
-    (void)background;
-    (void)blink;
-  }
+      bool blink = false) : foreground(foreground), background(background), blink(blink) {}
 } __attribute__((packed));  // prevent padding by the compiler
 
 /*! \brief Set the keyboard hardware cursor to absolute screen position