This removes the need for doing an extra pointer dereference on every
access to the buffers, shrinking the code by around 100 bytes.
The members for these buffers must be public for now, since the
interrupt handlers also need to access them. These can later be made
private again.
Furthermore, the struct ring_buffer was removed. This allows the all
head and tail pointers to be put into the HardwareSerial struct before
the actual buffers, so the pointers all end up in the first 32 bytes of
the struct that can be accessed using a single instruction (ldd).
References: #947
Since the buffers aren't bigger than 64 bytes, these values can be
smaller. This saves a few bytes of ram, but also saves around 50 bytes
of program space, since the values can now be loaded using a single
instruction.
To prevent problems when people manually increase the buffer size, a
compile-time check is added.
Closes: #1078
Otherwise, you get an error when compiling for processors with no serial port because the header file is always compiled.
See, for an example of the problem: https://github.com/damellis/attiny/issues/8
Made some helper class for files filtering.
platforms.txt now contains only one platform at a time.
Some cleanup in Compiler and AvrDudeUploader classes.
Cristian Maglie
Matthijs Kooijman
David A. Mellis