1 files changed, 4 insertions, 0 deletions
diff --git a/libraries/SoftwareSerial/SoftwareSerial.h b/libraries/SoftwareSerial/SoftwareSerial.h
index 2b12598..e28da98 100644
--- a/libraries/SoftwareSerial/SoftwareSerial.h
+++ b/libraries/SoftwareSerial/SoftwareSerial.h
@@ -56,6 +56,7 @@ private:
   volatile uint8_t *_pcint_maskreg;
   uint8_t _pcint_maskvalue;
 
+  // Expressed as 4-cycle delays (must never be 0!)
   uint16_t _rx_delay_centering;
   uint16_t _rx_delay_intrabit;
   uint16_t _rx_delay_stopbit;
@@ -78,6 +79,9 @@ private:
   void setRX(uint8_t receivePin);
   void setRxIntMsk(bool enable) __attribute__((__always_inline__));
 
+  // Return num - sub, or 1 if the result would be < 1
+  static uint16_t subtract_cap(uint16_t num, uint16_t sub);
+
   // private static method for timing
   static inline void tunedDelay(uint16_t delay);