I'm looking for suggestions on how to code busy-waiting semaphores in Redcode. The lack of an atomic test-and-set operation complicates matters.
The code below works for up to three processes, but under certain circumstances can fail with four processes. The entry points are wait and signal.
semaphore: dat 1
fail: add #1, semaphore
wait: djn fail, semaphore
signal: add #1, semaphore
If you have any suggestions, please let me know in the comments below.