Test and Set Lock (TSL) Definition

The test and set lock (TSL) is a hardware instruction that is provided by the CPU.
int TSL(int lock); /* prototype specification of TSL */

    e.g.     (* Pascal pseudo language implementation of Test and Set lock*)
               function Test-and-Set(var target: boolean): boolen;
                   begin
                              Test-and-Set := target;
                               target := true;
                    end;

It reads the contents of the memory word into a register and then stores a nonzero value at the memory address
The operations of reading and storing (i.e. writing) the memory word are gauranteed to be indivisible (i.e. atomic)

This page is maintained by Christopher A. Gantz (cag@cs.du.edu).