initial commit, compiles for ATTINY84 with TX on PA5 and RX on PA6

fifo.c

@@ -0,0 +1,27 @@
+#include "fifo.h"
+
+void fifo_init (fifo_t *f, uint8_t *buffer, const uint8_t size)
+{
+	f->count = 0;
+	f->pread = f->pwrite = buffer;
+	f->read2end = f->write2end = f->size = size;
+}
+
+uint8_t fifo_put (fifo_t *f, const uint8_t data)
+{
+	return _inline_fifo_put (f, data);
+}
+
+uint8_t fifo_get_wait (fifo_t *f)
+{
+	while (!f->count);
+	
+	return _inline_fifo_get (f);	
+}
+
+int fifo_get_nowait (fifo_t *f)
+{
+	if (!f->count)		return -1;
+		
+	return (int) _inline_fifo_get (f);	
+}