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+\ Semaphores (Source: B. Rodriguez)
+\ cvariable sem1
+\ : read sem1 wait do-something sem1 signal ;
+\ do-something has the ressource controlled by sem1 exlusivly
+\ wait can be used to communicate with interrupt service routines too
+\
+: wait ( addr - )
+ begin pause dup c@ until \ wait for non-zero = available
+ 0 swap c!
+;
+
+: signal ( addr -- )
+ 1 swap c! \ non-zero means available
+;
+