Remove undefined behavior from the startup conditions #132
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Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>
Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>
Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>
arjo129
approved these changes
Sep 24, 2024
luca-della-vedova
approved these changes
Sep 24, 2024
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I noticed a very non-deterministic behavior where sometimes one or more lifts would be unable to function from the moment the simulation started, and nothing seemed to allow them to recover. This would only happen once in a while and there was no consistency except that it happened immediately at startup and not under any other circumstance.
After some debugging I found that the
DoorModeCmpfor lifts was being initialized without a specific value set for thedoor_state. Most of the time memory used by programs will be zero-initialized, so most of the time thedoor_statefield was getting set to 0, which coincidentally gives us the correct behavior. But a zero-initialization is not guaranteed, so when that doesn't happen thedoor_statefield will be some arbitrary number, and then the state machine for the lift will just never be functional.This PR simply makes sure that field is set to the correct value at initialization. I haven't seen the bug happen again after this fix.