use enum

arch/cga.cc

@@ -1,10 +1,21 @@
 #include "cga.h"
+#include "arch/ioport.h"
 
 namespace CGA {
 
+  IOPort index_port = IOPort(0x3d4);
+  IOPort data_port  = IOPort(0x3d5);
+
+  void writeCGAReg(int reg, int data){
+    index_port.outb(reg);
+    data_port.outb(data);
+  }
+
 void setCursor(unsigned abs_x, unsigned abs_y) {
-  (void)abs_x;
-  (void)abs_y;
+	uint16_t pos = abs_y * COLUMNS + abs_x;
+
+  writeCGAReg(RegisterIndex::CURSOR_LOW, pos & 0xFF);
+  writeCGAReg(RegisterIndex::CURSOR_HIGH, ((pos >> 8) & 0xFF));
 }
 
 void getCursor(unsigned& abs_x, unsigned& abs_y) {

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