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18.1.1 Two-Level Classification

 

Every exceptional event in EMulatR carries a two-level classification. The high-level PendingEventKind (exceptionLib/PendingEventKind.h) distinguishes the broad event category:

 

enum class PendingEventKind : quint8 {

 None = 0,

 Exception, // Synchronous fault/trap

 Interrupt, // Asynchronous interrupt

 Ast, // Asynchronous System Trap

 MachineCheck, // Machine check (non-maskable)

 Reset, // Reset/wakeup

 PalCall // CALL_PAL event

};

 

The fine-grained ExceptionClass_EV6 (exceptionLib/ExceptionClass_EV6.h) carries 32 values that determine the specific PAL vector and delivery semantics. The full enumeration includes: Reset, MachineCheck, InternalProcessorError, BugCheck, Arithmetic, Interrupt, DStream, ItbMiss, ItbAcv, OpcDec, Fen, Unalign, Dfault, DtbAcv, Dtb_miss_double_4, Dtb_miss_single, Dtb_miss_native, MT_FPCR, IllegalInstruction, MemoryFault, SoftwareTrap, BreakPoint, Panic, PrivilegeViolation, ReservedOperand, CallPal, and others.

 

The design principle: pipeline code creates a PendingEvent with an ExceptionClass. The FaultDispatcher resolves the PalVectorId during delivery preparation. Detection and delivery are decoupled — the same PendingEvent structure flows through both phases.

 

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18.1.2 EventPriority

 

Each event carries an EventPriority that determines dispatch order when multiple events are pending simultaneously:

 

 

When multiple events are pending, the FaultDispatcher delivers the highest-priority event first. Lower-priority events remain queued until the higher-priority event is resolved.

 

See Also: exceptionLib/PendingEventKind.h; exceptionLib/ExceptionClass_EV6.h; 7.2 Terminology and Classification; 7.7 Priority Ordering.