Move interrupt handlers into HardwareSerial class

The actual interrupt vectors are of course defined as before, but they
let new methods in the HardwareSerial class do the actual work. This
greatly reduces code duplication and prepares for one of my next commits
which requires the tx interrupt handler to be called from another
context as well.

The actual content of the interrupts handlers was pretty much identical,
so that remains unchanged (except that store_char was now only needed
once, so it was inlined).

Now all access to the buffers are inside the HardwareSerial class, the
buffer variables can be made private.

One would expect a program size reduction from this change (at least
with multiple UARTs), but due to the fact that the interrupt handlers
now only have indirect access to a few registers (which previously were
just hardcoded in the handlers) and because there is some extra function
call overhead, the code size on the uno actually increases by around
70 bytes. On the mega, which has four UARTs, the code size decreases by
around 70 bytes.

1 files changed, 5 insertions, 1 deletions

diff --git a/cores/arduino/HardwareSerial.h b/cores/arduino/HardwareSerial.h
index 5513226..cf3f6bd 100644
--- a/cores/arduino/HardwareSerial.h
+++ b/cores/arduino/HardwareSerial.h
@@ -74,7 +74,6 @@ class HardwareSerial : public Stream
     volatile uint8_t *_udr;
     bool transmitting;
 
-  public:
     volatile uint8_t _rx_buffer_head;
     volatile uint8_t _rx_buffer_tail;
     volatile uint8_t _tx_buffer_head;
@@ -86,6 +85,7 @@ class HardwareSerial : public Stream
     unsigned char _rx_buffer[SERIAL_BUFFER_SIZE];
     unsigned char _tx_buffer[SERIAL_BUFFER_SIZE];
 
+  public:
     HardwareSerial(
       volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
       volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
@@ -104,6 +104,10 @@ class HardwareSerial : public Stream
     inline size_t write(int n) { return write((uint8_t)n); }
     using Print::write; // pull in write(str) and write(buf, size) from Print
     operator bool() { return true; }
+
+    // Interrupt handlers - Not intended to be called externally
+    void _rx_complete_irq(void);
+    void _tx_udr_empty_irq(void);
 };
 
 #if defined(UBRRH) || defined(UBRR0H)