When the CPU detects the fatal error, the CPU enters FATAL error_state and reports the fatal error occurrence to the system controller. The system controller transfers the entire system state to the FATAL state and stops the system. After the system stops, a FATAL reset, which is a type of power-on reset, will be issued to the whole system.

P.1.2 error_state Transition Error

An error_state transition error is a serious error that prevents the CPU from reporting the error by generating a trap. However, any damage caused by the error is limited to within the CPU.

When the CPU detects an error_state transition error, it enters error_state. The CPU exits error_state by causing a watchdog reset, entering RED_state, and starting instruction execution at the watchdog reset trap handler.

P.1.3 Urgent Error

An urgent error (UGE) is an error that requires immediate processing by privileged software, which is reported by an error trap. The types of urgent errors are listed below and then described in further detail.

Instruction-obstructing error

I_UGE: Instruction urgent error

IAE: Instruction access error

DAE: Data access error

Urgent error that is independent of the instruction execution

A_UGE: Autonomous urgent error

Instruction-Obstructing Error

An instruction-obstructing error is one that is detected by instruction execution and results in the instruction being unable to complete.

When the instruction-obstructing error is detected while

ASI_ERROR_CONTROL.WEAK_ED = 0 (as set by privileged software for a normal program execution environment), then an exception is generated to report the error. This trap is nonmaskable.

Otherwise, when ASI_ERROR_CONTROL.WEAK_ED = 1, as with multiple errors or a POST/OBP reset routine, one of the following actions occurs:

Whenever possible, the CPU writes an unpredictable value to the target of the damaged instruction and the instruction ends.

150 SPARC JPS1 Implementation Supplement: Fujitsu SPARC64 V • Release 1.0, 1 July 2002

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Fujitsu Fujitsu SPARC64 V manual Errorstate Transition Error, Urgent Error, Instruction-Obstructing Error