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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
177
Intel XScale
®
Processor—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
When setting multiple CP15 registers, system software may opt to delay the assurance
of their update. This is accomplished by executing CPWAIT only after the sequence of
MCR instructions.
The CPWAIT sequence guarantees that CP15 side-effects are complete by the time the
CPWAIT is complete. It is possible, however, that the CP15 side-effect will take place
before CPWAIT completes or is issued. Programmers should take care that this does
not affect the correctness of their code.
3.8.3.4
Event Architecture
3.8.3.4.1
Exception Summary
shows all the exceptions that the Intel XScale processor may generate, and
the attributes of each. Subsequent sections give details on each exception.
3.8.3.4.2
Event Priority
The Intel XScale processor follows the exception priority specified in the ARM*
Architecture Reference Manual. The processor has additional exceptions that might be
generated while debugging. For information on these debug exceptions, see
.
Table 75.
Exception Summary
Exception Description
Exception Type
Precise
Updates FAR
Reset
Reset
N
N
FIQ
FIQ
N
N
IRQ
IRQ
N
N
External Instruction
Prefetch
Y
N
Instruction MMU
Prefetch
Y
N
Instruction Cache Parity
Prefetch
Y
N
Lock Abort
Data
Y
N
MMU Data
Data
Y
Y
External Data
Data
N
N
Data Cache Parity
Data
N
N
Software Interrupt
Software Interrupt
Y
N
Undefined Instruction
Undefined Instruction
Y
N
Debug Events
varies
varies
N
Notes:
1.
Exception types are those described in the Intel
®
StrongARM
*
manual, section 2.5.
2.
Refer to
for more details
Table 76.
Event Priority
Exception
Priority
Reset
1 (Highest)
Data Abort (Precise & Imprecise)
2
FIQ
3
IRQ
4
Prefetch Abort
5
Undefined Instruction, SWI
6 (Lowest)