-#define buffered_addr_h(a) \
- extern volatile u8* _##a
-
-buffered_addr_h(switch_input);
-buffered_addr_h(misc_input);
-buffered_addr_h(home_sensors);
-buffered_addr_h(changer_output);
-buffered_addr_h(misc_output);
-
-/******* from display.c *******/
-
-/* scrolling modes */
-#define WRAP_SCROLL_L 1 /* scroll to the left */
-#define WRAP_SCROLL_R 1 /* scroll to the right */
-#define WRAP_ALTERNATE 2 /* alternate between text */
-
-extern char current_message[1024];
-
-void display_init();
-void set_msg(char* newmsg);
-void set_wrap_mode(u8 new_wrap_mode);
-void display_refresh();
+/* to add more addresses, define them here with buffered_addr_h, in helpers.c
+ * with buffered_addr, and also in LDFLAGS in the Makefile
+ */
+#define buffered_addr(a) \
+ extern volatile u8* _##a; \
+ u8 a; \
+ extern inline void set_##a(u8 b) { a = *_##a = b; } \
+ extern inline void bset_##a(u8 m) { a |= m; *_##a = a; } \
+ extern inline void bclr_##a(u8 m) { a &= ~m ; *_##a = a; }
+
+buffered_addr(switch_input);
+buffered_addr(misc_input);
+buffered_addr(home_sensors);
+buffered_addr(changer_output);
+buffered_addr(misc_output);
+
+extern inline void spi_enable() { _io_ports[M6811_SPCR] |= M6811_SPE; }
+extern inline void spi_disable() { _io_ports[M6811_SPCR] &= ~M6811_SPE; }
+
+/******* from helpers.c *******/