n
Shared variable b is
initialized to 0
n
Each Pi has a local
variable k
n
The only Pi that can
enter CS is the one
who finds b=0
n
This Pi excludes all
the other Pj by setting
b to 1
Process Pi:
repeat
k:=1
repeat xchg(k,b)
until k=0;
CS
b:=0;
RS
forever