(Mill team) With apologies to those tired of hearing about the new Mill CPU let me explain how the Mill traps on integer overflow: For overflow-able arithmeti

(Mill team) With apologies to those tired of hearing about the new Mill CPU let me explain how the Mill traps on integer overflow: For overflow-able arithmetic operations, we support four modes: * truncate * except * saturate * double-width With excepting overflow, the result is marked as invalid (we term it "Not-a-Result (NaR)"). As these invalid results are used in further computation, the NaR propagates. When you finally use the result in non-speculatively e.g. store it or branch on it then the hardware faults. NaRs have lots of other uses. This is described in the Metadata talk http://millcomputing.com/topic/metadata/ http://millcomputing.com/topic/metadata/ And http://millcomputing.com/topic/introduction-to-the-mill-cpu-programming-model-2/ http://millcomputing.com/topic/introduction-to-the-mill-cpu-... for a broader overview.