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The test-and-set instruction
nA C++ description of test-and-set:
nAn algorithm that
uses testset for Mutual Exclusion:
nShared variable b is
initialized to 0
nOnly the first Pi who sets b enter CS
bool testset(int& i)
{
if (i==0) {
i=1;
return true;
} else {
return false;
}
}
Process Pi:
repeat
repeat{}
until testset(b);
CS
b:=0;
RS
forever