Added simple pixel graphics

Signed-off-by: Cestmir Houska <czestmyr@gmail.com>

gfx.c

@@ -0,0 +1,35 @@
+#include "gfx.h"
+
+void init_graphics() {
+#asm
+    mov al, #0x13
+    mov ah, #0x0
+    int 0x10
+#endasm
+}
+
+void put_pixel(x, y, color)
+    int x;
+    int y;
+    char color;
+{
+    x = x + y*320;
+#asm
+    mov ax, #0xa000
+    mov es, ax
+    mov al, _put_pixel.color[bp]
+    mov di, _put_pixel.x[bp]
+    seg es
+    mov [di], al
+#endasm
+
+}
+
+void deinit_graphics() {
+#asm
+    mov al, #0x12
+    mov ah, #0x0
+    int 0x10
+#endasm
+}
+