diff options
| -rw-r--r-- | cores/arduino/HardwareSerial.cpp | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp index 5cd89e5..75e079f 100644 --- a/cores/arduino/HardwareSerial.cpp +++ b/cores/arduino/HardwareSerial.cpp @@ -26,6 +26,7 @@ #include <stdio.h> #include <string.h> #include <inttypes.h> +#include <util/atomic.h> #include "Arduino.h" #include "HardwareSerial.h" @@ -76,6 +77,13 @@ void serialEventRun(void) #endif } +// macro to guard critical sections when needed for large TX buffer sizes +#if (SERIAL_TX_BUFFER_SIZE>256) +#define TX_BUFFER_ATOMIC ATOMIC_BLOCK(ATOMIC_RESTORESTATE) +#else +#define TX_BUFFER_ATOMIC +#endif + // Actual interrupt handlers ////////////////////////////////////////////////////////////// void HardwareSerial::_tx_udr_empty_irq(void) @@ -177,15 +185,13 @@ int HardwareSerial::read(void) int HardwareSerial::availableForWrite(void) { -#if (SERIAL_TX_BUFFER_SIZE>256) - uint8_t oldSREG = SREG; - cli(); -#endif - tx_buffer_index_t head = _tx_buffer_head; - tx_buffer_index_t tail = _tx_buffer_tail; -#if (SERIAL_TX_BUFFER_SIZE>256) - SREG = oldSREG; -#endif + tx_buffer_index_t head; + tx_buffer_index_t tail; + + TX_BUFFER_ATOMIC { + head = _tx_buffer_head; + tail = _tx_buffer_tail; + } if (head >= tail) return SERIAL_TX_BUFFER_SIZE - 1 - head + tail; return tail - head - 1; } |