cga mostly done

arch/cga.cc

@@ -32,9 +32,6 @@ void getCursor(unsigned& abs_x, unsigned& abs_y) {
 }
 
 void show(unsigned abs_x, unsigned abs_y, char character, Attribute attrib) {
-  (void)abs_x;
-  (void)abs_y;
-  (void)character;
-  (void)attrib;
+  TEXT_BUFFER_BASE[abs_x + (COLUMNS * abs_y)] = Cell(character, attrib);
 }
 };  // namespace CGA

arch/cga.h

@@ -136,5 +136,5 @@ struct Cell {
 
 /*! \brief Base address for linear text buffer in video memory
  */
-Cell* const TEXT_BUFFER_BASE = nullptr;
+Cell* const TEXT_BUFFER_BASE = reinterpret_cast<CGA::Cell*>(0xb8000);
 };  // namespace CGA

main.cc

@@ -10,13 +10,15 @@ extern "C" int main() {
   unsigned int numCPUs = Core::count();
   DBG_VERBOSE << "Number of CPUs: " << numCPUs << endl;
 
-  CGA::setCursor(0, 0);
-
+  //test cga implemantation
+  CGA::setCursor(1, 2);
   unsigned x,y;
   CGA::getCursor(x, y);
-
   CGA::setCursor(x+1, y+1);
 
+  for(uint8_t i = 0; i < 10; i++)
+    CGA::show(i, i, i+0x30, CGA::Attribute());
+
   /* Start application processors
    * To avoid unexpected behaviour, make sure that interrupts are not
    * enabled before the APs are booted. Otherwise it might interfere with the