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