1. Fetch And Add – switching network
S = S + inc as executed by 8 processors
inc
2 5
3 2
9 4
7 1 9 2 7 3 5 7 15 18 15
First Stage: Incrementing Memory
S + 33
register
S: memory

2. Fetch And Add – switching network
S = S + inc S=
Inc=
2 5
3 2
9 4
7 1 39 10 9 2 7 3 5 7 10 25 15
Second Stage: Returning Value
O (log P)
S =10
Left: pass # up
Right: # + register
S =
S: memory