EFTON - Microcontroller programming 101.01

Microcontroller programming 101.01: Ring Buffers

Work in progress

pattern

head, tail, MAX, buf[MAX] (i.e. head/tail go from 0 to MAX-1; tail points to first byte about to go out, head points to first empty byte into which new byte will come in)


                  occup             free

head >= tail      head - tail         MAX - 1 - (head - tail) = 
 MAX + tail - head - 1 

 head < tail   MAX + head - tail   MAX - 1 - (MAX + head - tail) = 
  tail - head - 1

	occup	free
head >= tail	head - tail	MAX - 1 - (head - tail) = MAX + tail - head - 1
head < tail	MAX + head - tail	MAX - 1 - (MAX + head - tail) = tail - head - 1

Atomicity up and down