FUJITSU Implementation Supplement Fujitsu SPARC64 V - Manual (Page 162)

Release 1.0, 1 July 2002 F. Chapter P Error Handling 151
■ 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_UGE s.
■
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_UGE s:
■
An error in an important resource that will cause a fatal error or
error_state transition error when the resource is used.