Fujitsu Fujitsu SPARC64 V manual Urgent Error Independent of Instruction Execution

■Otherwise, an error exception is generated and the damaged instruction is executed as when ASI_ERROR_CONTROL.WEAK_ED = 0 is set.

The three types of instruction-obstructing errors are described below.

■I_UGE (instruction urgent error) — All of the instruction-obstructing errors except IAE (instruction access error) and DAE (data access error). There are two categories of I_UGEs.

■An uncorrectable error in an internal program-visible register that obstructs instruction execution.

An uncorrectable error in the PSTATE, PC, NPC, CCR, ASI, FSR, or GSR register is treated as an I_UGE that obstructs the execution of any instruction. See Sections P.8.1 and P.8.2 for details.

The first-time watchdog timeout is also treated as this type of I_UGE.

■An error in the hardware unit executing the instruction, other than an error in a program-visible register.

Among these errors are ALU output errors, errors in temporary registers during instruction execution, CPU internal data bus errors, and so forth.

I_UGE is a preemptive error with the characteristics shown in TABLE P-2.

■IAE (instruction access error) — The instruction_access_error exception, as specified in JPS1 Commonality. On SPARC64 V, only an uncorrectable error in the cache or main memory during instruction fetch is reported to software as an IAE.

IAE is a precise error.

■DAE (data access error) — The data_access_error exception, as specified in JPS1 Commonality. On SPARC64 V, only an uncorrectable error in the cache or main memory during access by a load, store, or load-store instruction is reported to software as a DAE.

DAE is a precise error.

Urgent Error Independent of Instruction Execution

■A_UGE (Autonomous Urgent Error) — An error that requires immediate processing and that occurs independently of instruction execution.

In normal program execution, ASI_ERROR_CONTROL.WEAK_ED = 0 is specified by privileged software. In this case, the A_UGE trap is suppressed only in the trap handler used to process UGE (that is, the async_data_error trap handler).

Otherwise, in special program execution such as the handling of the occurrence of multiple errors or the POST/OBP reset routine, ASI_ERROR_CONTROL.WEAK_ED = 1 is specified by the program. In this case, no A_UGE generates an exception.

There are two categories of A_UGEs:

■An error in an important resource that will cause a fatal error or error_state transition error when the resource is used.

Release 1.0, 1 July 2002 F. Chapter P Error Handling 151