diff options
| -rw-r--r-- | cores/arduino/HardwareSerial.cpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp index 1a2f8ce..2a256e0 100644 --- a/cores/arduino/HardwareSerial.cpp +++ b/cores/arduino/HardwareSerial.cpp @@ -53,6 +53,8 @@ // using a ring buffer (I think), in which head is the index of the location // to which to write the next incoming character and tail is the index of the // location from which to read. +// NOTE: a "power of 2" buffer size is reccomended to dramatically +// optimize all the modulo operations for ring buffers. #if (RAMEND < 1000) #define SERIAL_BUFFER_SIZE 16 #else @@ -426,7 +428,7 @@ void HardwareSerial::end() int HardwareSerial::available(void) { - return (int)(SERIAL_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % SERIAL_BUFFER_SIZE; + return ((unsigned int)(SERIAL_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail)) % SERIAL_BUFFER_SIZE; } int HardwareSerial::peek(void) |