Define a _NOP() macro

Recent avr-libc releases define one, but this allows using it also on
older avr-libc releases.

1 files changed, 4 insertions, 0 deletions

diff --git a/cores/arduino/Arduino.h b/cores/arduino/Arduino.h
index 7bf5119..8502e44 100644
--- a/cores/arduino/Arduino.h
+++ b/cores/arduino/Arduino.h
@@ -88,6 +88,10 @@ void yield(void);
 #define bitClear(value, bit) ((value) &= ~(1UL << (bit)))
 #define bitWrite(value, bit, bitvalue) (bitvalue ? bitSet(value, bit) : bitClear(value, bit))
 
+// avr-libc defines _NOP() since 1.6.2
+#ifndef _NOP
+#define _NOP() do { __asm__ volatile ("nop"); } while (0)
+#endif
 
 typedef unsigned int word;